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Children's Interneted Physical Immortality Education System
Fragments from internet source url = http://www.bbc.co.uk/science/horizon/1999/diamonds_script.shtml
The Diamond Makers BBC2 9:30pm Thursday 27th January 2000
"STEPHEN LUSSIER (Marketing Director, De Beers):
There's something magical about diamonds. They've captured the imagination of people for so long I think it's things like, you know, the fact that they are 3 billion years old, the fact that it takes enormous effort to find diamonds in the world, it takes even more enormous effort to get them out. They have this magnificent way of dealing with light that separates them from all the other precious stones. They really are just a miracle of nature.
STEPHEN LUSSIER: The consumer actually wants a piece of forever. That's what a diamond is. It's a promise of forever.
INSERTION BY ROBERT RAY HEDGES: [Google's current top in Physical Immortality] (Oct 2005)
Just as Mr Lussier has said "The consumer actually wants a piece of forever." That's what creating Physical Immortality is. It's a promise of ACTUALLY LIVING forever PHYSICALLY.
We need diamond microchips to do it (super computers in every house) and we will create companies that transfer large portions of synthetic diamond sales profits into both Synthetic Diamond Research and Developement and into the Mortality Resolution International Project.
Children will oversee this Imperative once they've been informed over the internet that they have been created to be killed or die.
Bryant Linares of Apollo Diamond in Boston, Massachusettes, USA
Carter Clark of Gemesis.Com in Sarasota, Florida, USA
Pressuring the Diamond Business: ^Link^
DeBeers Fears: Photo
Perfect and the Clearest Strongest Diamonds in the World are coming out of the Woodwork now! [Feb 2004]
CopyRighted Diamond Photo
Pix, White
Pix, Color
MICROPROCESSORS are getting TOO HOT, requiring too much power, and not delivering enough additional performance for it. That's the basic problem. The engine that's driven the microcomputer's incredible rise in capability over the past 30 years, Moore's Law, isn't quite out of steam yet, but some of its offshoots are on the ropes. CPU designers have nearly exhausted their collective bag of tricks to get more performance out of additional transistors on a chip by increasing parallelism at the instruction level. Speculative execution and deep pipelining are by now very standard features, and CPU designs are getting increasingly complex and hard to manage. When Gordon Moore's goose lays a golden egg and the number of transistors possible on a chip doubles, as it is supposed to do every 18 months, taking advantage of the windfall has proven increasingly difficult. synthetic Diamonds
Codex5002 Before the 1930s, the gems of choice for engagement rings included opals, rubies, and sapphires. But in the 1940s, De Beers--the South African mining firm that controls the majority of the world's diamond supply--introduced "A Diamond Is Forever." Interestingly, diamond based computers will help usher in the Era of Immortality of our bodies. Diamonds may, additionally, be used to finance our own personal forever!
Polycrystalline diamond can be grown by a number of different CVD techniques, including microwave plasma assisted chemical vapour deposition, hot filament deposition, plasma jet deposition and combustion flame deposition.
The success of this campaign turned diamond into the symbol of eternal love and dramatically increased demand for the gems. ref url= http://pubs.acs.org/cen/coverstory/8205/8205diamonds.html Diamond-Microchips.Com, Diamond Substrates, Diamond Microprocessors, Diamond Wafers, Diamond Wafer Evolution Quantum Ethics
Military Applications for Diamond Microchips; AeroSpace Space Applications for Diamond Microchips!
Military planning is not generally placed in Full Public View for National Security Reasoning;
Speculations, however, are welcome right here......Certainly out-computing the "Enemy" is just too obvious....so what amount of budgeting will occur? Hmmm!
Recent observations and interpretations are currently leaning toward a cataytic affect of the presence of a large hydrogen gas population during CVD diamond growth that involves the formation of a carburized layer on the diamond substrate that is converted to diamond by atomic hydrogen.
"30 Torr using hydrogen and methane gases with flow rates of 200 sccm and 1 sccm, respectively. The substrates were heated to 800 degrees C using a tantalum foil as the heating element. The tungsten filament temperature was 2200 degrees C, as measured using a disappearingfilament optical pyrometer" (search for internet source using sentence fragments as search terms[use""])
The influence of bias on gaseous composition and diamond growth in a hot-filament chemical vapour deposition process J B Cui and R C Fang, Department of Physics, Structure Research Laboratory,
University of Science and Technology of China, Hefei 230026,
People's Republic of China Received 7 May 1996
Print publication: Issue 11 (14 November 1996)
Abstract.
In situ optical emission spectroscopy has been used to measure the direct current biased hot-filament diamond deposition processes for gas mixtures of methane, argon and hydrogen. The effects of bias on diamond growth and optical emission were investigated. The increase of bias voltage slightly raises the atomic hydrogen concentration which is estimated by using the Ar (750 nm) line as actinometry. The bias has little influence on hydrocarbon species and electron temperature. The enhancement of diamond nucleation and smoothing of the film surface by positive bias are mainly caused by electron bombardment on the surface of the substrate and growing film rather than on the change of gaseous environment.
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Fancy Diamonds
Paul [Wired Mag] Revered: Man Made Diamonds are Coming;De Beers has a Sobering Moment
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The Future and Its Impact
Catching Up with Moore's Law
Diamond Attributes
Nature and Man are One and INSEPARABLE in Physical Immortality
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Diamond Pictures Wafer Wafers carbonado bort scale.....
The name diamond comes from a Greek word adamas [meaning invincible], and was applied by the Greeks to all hard stones.... such as corundum.
Diamond films with optical transparency and high thermal conductivity have been synthesized by the seven [multi-cathode] direct current plasma assisted CHEMICAL VAPOR DEPOSITION method. Diamond wafers have been grown on the metal substrates with 76 mm diameter under the deposition pressure of 100 Torr and the input power of 15 kW, respectively. Synthesized free-standing diamond films have been polished and their Ra values range several tens nm.
Optical(visible and IR range) and thermal properties of diamond films have been observed. Depending on the methane concentrations, there were large differences in the measured values. A transparent diamond wafer deposited at an optimum condition showed high transmission of 70 % at the 10.6 mm wavelength and high thermal conductivity of 21 W/cmK at room temperature. Variations of transmission and thermal conductivity within a wafer were ± 10%. The tangent loss and Raman spectroscopy of the diamond films have been measured and the included impurity levels have been determined analysis depending on the wafer location and the film thickness by RBS measurement.
Ref url: internet address http://www.eng.auburn.edu/department/ee/ADC-FCT2001/ADCFCTabstract/050.htm Diamond Wafers Diamond Substrates, Diamond MicroProcessors, and Diamond Microchips
Diamond Microchips Diamond Pictures and Diamond MicroProcessors, Diamond Wafers and Diamond Wafer Physics
Thermal Conductivity
Apollo diamond has been tested with thermal conductivities exceeding
3000 w/m K, almost double that of polycrystalline diamond, and exceeding
the best mined diamond.
Armed with inexpensive, mass-produced gems, two startups are launching an assault on the De Beers cartel.
Next up: the computing industry. By Joshua Davis (DC PACVD)
Bryant Linares Aron Weingarten Aron Weingarten brings the yellow diamond up to the stainless steel jeweler's loupe he holds against his eye. We are in Antwerp, Belgium, in Weingarten's marbled and gilded living room on the edge of the city's gem district, the center of the diamond universe. Nearly 80 percent of the world's rough and polished diamonds move through the hands of Belgian gem traders like Weingarten, a dealer who wears the thick beard and black suit of the Hasidim.
David Clugston
Yellow diamonds manufactured by Gemesis, the first company to market gem-quality synthetic stones. The largest grow to 3 carats.
"This is very rare stone," he says, almost to himself, in thickly accented English. "Yellow diamonds of this color are very hard to find. It is probably worth 10, maybe 15 thousand dollars."
"I have two more exactly like it in my pocket," I tell him.
He puts the diamond down and looks at me seriously for the first time. I place the other two stones on the table. They are all the same color and size. To find three nearly identical yellow diamonds is like flipping a coin 10,000 times and never seeing tails.
"These are cubic zirconium?" Weingarten says without much hope.
"No, they're real," I tell him. "But they were made by a machine in Florida for less than a hundred dollars."
Blue Diamonds
Man Made Diamonds: More History
Ian White
A microwave plasma tool at the Naval Research Lab, used to create diamonds for high-temperature semiconductor experiments.
Weingarten shifts uncomfortably in his chair and stares at the glittering gems on his dining room table. "Unless they can be detected," he says, "these stones will bankrupt the industry."
Put pure carbon under enough heat and pressure - say, 2,200 degrees Fahrenheit and 50,000 atmospheres - and it will crystallize into the hardest material known. Those were the conditions that first forged diamonds deep in Earth's mantle 3.3 billion years ago. Replicating that environment in a lab isn't easy, but that hasn't kept dreamers from trying. Since the mid-19th century, dozens of these modern alchemists have been injured in accidents and explosions while attempting to manufacture diamonds.
Recent decades have seen some modest successes. Starting in the 1950s, engineers managed to produce tiny crystals for industrial purposes - to coat saws, drill bits, and grinding wheels. But this summer, the first wave of gem-quality manufactured diamonds began to hit the market. They are grown in a warehouse in Florida by a roomful of Russian-designed machines spitting out 3-carat roughs 24 hours a day, seven days a week. A second company, in Boston, has perfected a completely different process for making near-flawless diamonds and plans to begin marketing them by year's end. This sudden arrival of mass-produced gems threatens to alter the public's perception of diamonds - and to transform the $7 billion industry. More intriguing, it opens the door to the development of diamond-based semiconductors.
Diamond, it turns out, is a geek's best friend. Not only is it the hardest substance known, it also has the highest thermal conductivity - tremendous heat can pass through it without causing damage. Today's speedy microprocessors run hot - at upwards of 200 degrees Fahrenheit. In fact, they can't go much faster without failing. Diamond microchips, on the other hand, could handle much higher temperatures, allowing them to run at speeds that would liquefy ordinary silicon. But manufacturers have been loath even to consider using the precious material, because it has never been possible to produce large diamond wafers affordably. With the arrival of Gemesis, the Florida-based company, and Apollo Diamond, in Boston, that is changing. Both startups plan to use the diamond jewelry business to finance their attempt to reshape the semiconducting world.
But first things first. Before anyone reinvents the chip industry, they'll have to prove they can produce large volumes of cheap diamonds. Beyond Gemesis and Apollo, one company is convinced there's something real here: De Beers Diamond Trading Company. The London-based cartel has monopolized the diamond business for 115 years, forcing out rivals by ruthlessly controlling supply. But the sudden appearance of multicarat, gem-quality synthetics has sent De Beers scrambling. Several years ago, it set up what it calls the Gem Defensive Programme - a none too subtle campaign to warn jewelers and the public about the arrival of manufactured diamonds. At no charge, the company is supplying gem labs with sophisticated machines designed to help distinguish man-made from mined stones.
Ian White
"I was in combat in Korea and 'Nam. You better believe that I can handle the diamond business," says Gemesis founder Carter Clarke, center. His lieutenants have 27 diamond-making machines up and running -- with 250 planned -- at this factory outside Sarasota, Florida
In its long history, De Beers has survived African insurrection, shrugged off American antitrust litigation, sidestepped criticism that it exploits third world workers, and contended with Australian, Siberian, and Canadian diamond discoveries. The firm has a huge advertising budget and a stranglehold on diamond distribution channels. But there's one thing De Beers doesn't have: retired brigadier general Carter Clarke.
Carter Clarke, 75, has been retired from the Army for nearly 30 years, but he never lost the air of command. When he walks into Gemesis - the company he founded in 1996 to make diamonds - the staff stands at attention to greet him. It just feels like the right thing to do. Particularly since "the General," as he's known, continually salutes them as if they were troops heading into battle. "I was in combat in Korea and 'Nam," he says after greeting me with a salute in the office lobby. "You better believe I can handle the diamond business."
Clarke slaps me hard on the back, and we set off on a tour of his new 30,000-square-foot factory, located in an industrial park outside Sarasota, Florida. The building is slated to house diamond-growing machines, which look like metallic medicine balls on life support. Twenty-seven machines are now up and running. Gemesis expects to add eight more every month, eventually installing 250 in this warehouse.
The New Diamond Microchip Diamond Microchips Age Bryant Linares http://diamond-microchips.com
In other words, the General is preparing a first strike on the diamond business. "Right now, we only threaten the way De Beers wants the consumer to think of a diamond," he says, noting that his current monthly output doesn't even equal that of a small mine. "But imagine what happens when we fill this warehouse and then the one next door," he says with a grin. "Then I'll have myself a proper diamond mine."
The New Diamond Microchip Diamond Microchips Age Bryant Linares http://diamond-microchips.com
Clarke didn't set out to become a gem baron. He stumbled into this during a 1995 trip to Moscow. His company at the time - Security Tag Systems - had pioneered those clunky antitheft devices attached to clothes at retail stores. Following up on a report about a Russian antitheft technology, Clarke came across Yuriy Semenov, who was in charge of the High Tech Bureau, a government initiative to sell Soviet-era military research to Western investors. Semenov had a better idea for the General: "How would you like to grow diamonds?"
Gemesis's Carter Clark: An Interview
More Amorous of Moore
from newsweek:
Nov. 1 issue - Bryant Linares has one heck of a secret family recipe: how to make world-class diamonds. Seven years ago his father, Robert, produced a diamond in a high-pressure chamber of carbon gas and dropped it into an acid solution to clean it off. When he returned the next morning, he expected to find the usual yellow stone—a crude artificial diamond of some use to industry, perhaps, but not the stuff of dreams. At first there didn't seem to be any stone at all. Then he saw, at the bottom of the beaker, so clear it was almost invisible, a perfect quarter-carat crystal of pure carbon. "It was the eureka moment," says Bryant. His father had managed what many scientists had given up on long ago: to manufacture a stone that wouldn't look out of place on an engagement ring.
Man-made diamonds are nothing new—industry started making them in the 1950s, and each year about 80 tons of low-quality synthetic diamonds are used in tools like drill bits and sanders. High-quality crystals, though, open up huge possibilities, jewelry being the least of them. Scientists are most excited about the prospect of making diamond microchips. As chips have shrunk over the years, engineers have struggled with ways of dissipating the heat they create. Because silicon, the main component of semiconductors, breaks down at about 95 degrees Hnds might fit the bill. They can withstand 500 degrees, and electrons move through them so easily that they would tend not to heat up in the —first place. Engineers could cram a lot more circuits onto a diamond-based microchip—if they could perfect a way of making pure crystals cheaply.
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Diamond Microchips Diamond Micro Chips Diamonds and their Synthesis Artificial Man Made Synthetic
Diamond MicroChips Dot Com, Diamonds MicroChips Dot Com, http://diamond-microchips.com/
Diamonds and their Synthesis
Diamond MicroChips Dot Com, Diamonds MicroChips Dot Com, http://diamond-microchips.com/
# Diamonds have been used in jewelery, especially in engagement rings for over six centuries.
REMARKABLE FACTS:
* All diamonds are at least 990,000,000 years old. Many are 3,200,000,000 years old (3.2 billion years)
* Diamonds are formed deep within the Earth: between 100 km and 200 km below the surface.
Diamonds form under remarkable conditions!
o The temperatures are about 900 - 1300 C in the part of the Earth's mantle where diamonds form
o The pressure is between 45 - 60 kilobars (kB)
+ 50 kB = 150 km = 90 miles below the surface
+ 60 kB = 200 km = 120 miles below the surface
* Diamonds are carried to the surface by volcanic eruptions.
Diamonds and their Synthesis
Diamond MicroChips Dot Com, Diamonds MicroChips Dot Com, http://diamond-microchips.com/
The volcanic magma conduit is known as a kimberlite pipe or diamond pipe. We find diamonds as inclusions in the (rather ordinary looking) volcanic rock known as kimberlite.
NOTE: The kimberlite magmas that carry diamonds to the surface are often much younger than the diamonds they transport (the kimberlite magma simply acts as a conveyer belt!).
* Diamond is made of carbon (C), yet the stable form (polymorph) of carbon at the Earth's surface is graphite.
* To ensure they are not converted to graphite, diamonds must be transported extremely rapidly to the Earth's surface.
It is probable that kimberlite lavas carrying diamonds erupt at between 10 and 30 km/hour (Eggler, 1989). Within the last few kilometers, the eruption velocity probably increases to several hundred km/hr (supersonic!).
Diamonds and their Synthesis
Diamond MicroChips Dot Com, Diamonds MicroChips Dot Com, http://diamond-microchips.com/
This movie (68 k) emphasises that diamonds do not form in the kimberlite magma, but are carried up to the surface by the magma.
* Diamond is the hardest material
Diamond is the hardest gem on MOHS harness scale and graphite (also made from carbon atoms) is the softest !! Given that both diamond and graphite are made of carbon, this may seem surprising.
Diamonds and their Synthesis
Diamond MicroChips Dot Com, Diamonds MicroChips Dot Com, http://diamond-microchips.com/
The explanation is found in the fact that in diamond the carbon atoms are linked together into a three-dimensional network whereas in graphite, the carbon atoms are linked into sheets with very little to hold the sheets together (thus the sheets slide past each other easily, making a very soft material).
# Diamonds are found in many localites, both overseas and in the US.
HOW RARE ARE DIAMONDS?
# How many grams do you need to mine to get 5 grams of diamonds?
(5g/1000 kg) @ 1000 g/kg = 5 g /1,000,000 g!
BUT only 20 % are gem quality (80 % of these are sold in a 'managed selling environment') and the remainder are used for industrial purposes (this material is known as 'bort' or 'carbonado' (carbonado is finer)).
Diamonds and their Synthesis
Diamond MicroChips Dot Com, Diamonds MicroChips Dot Com, http://diamond-microchips.com/
CHARACTERISTICS OF DIAMOND:
# Hardness = 10
# Crystal System = cubic
# This is what crystals look like before they are faceted: note their natural octahedral shape!
Uncut diamonds are also found in cubic forms
# Diamond has four good cleavages, thus diamonds tend to cleave on impact
# Other diagnostic properties.
Diamonds and their Synthesis
Diamond MicroChips Dot Com, Diamonds MicroChips Dot Com, http://diamond-microchips.com/
Famous diamonds
This is just for fun -- not required information!
1. Dresden
2. Hope ...the real thing!
3. Cullinan (Before)
* After
4. Sancy
5. Tiffany
6. Kohinor
* a-section
7. Shah
8. Nassau
9. Florentine
10. The Great Mogul
11. Orloff
12. Stern
13. Regent
VALUE
The 4 "C" words are used to summarize the value determining factors:
The required basic information describing what is meant by these terms is provided below.
Some further comments on the '4 C's from another remote source!
# (1) COLOR: is determined by 'grading' visual comparison with 'knowns' or by instrumental means.
o consider the amount of yellow color (yellowish color decreases the value of a "colorless" stone). In order of increasing yellow content:
blueish-white -> white -> silver -> yellow
o 'Fancy', or strongly colored stones have their own appeal and special value.
Colored diamonds may beyellow, green or brown, green or shades of pink
Larger pink diamonds are quite rare and currently very !! expensive.
Natural blue diamonds contain the element boron (B), and this changes the conductivity of the diamonds. Natural yellow diamonds contain the element nitrogen (N).
Diamonds and their Synthesis
Diamond MicroChips Dot Com, Diamonds MicroChips Dot Com, http://diamond-microchips.com/
# (2) CLARITY : Clarity is decreased by the presence of blemishes or flaws, scratches, nicks, 'naturals' (the original surface of an uncut stone). There are many systems of nomenclature.
Some terms include:
o flawless or perfect
o imperfect
o very slightly imperfect
o very very slightly imperfect
F1 VVS1 VVS2 VVS3 VS1 VS2 SI1 SI2 I1 I2 I3
flawless imperfect
other descriptions:
"first pique" inclusions readily recognizable at 10x mag., not significantly diminishing brilliance
"second pique" larger inclusions, can be seen with naked eye
"third pique" many large inclusions, diminishing brilliance
Diamonds and their Synthesis
Diamond MicroChips Dot Com, Diamonds MicroChips Dot Com, http://diamond-microchips.com/
Examples of clarity-reducing inclusions:
o inclusions
o cracks
o a crack along the pavillion
# (3) CUT
Facets are placed so as to maximize the brilliance and fire of a stone.
Remember that in the first lecture we talked about how the proportions of a faceted gemstone are determined based on the refractive index?
Review the basic concepts:
o Refraction is dependent upon the wavelength
o Refractive Index (RI) is proportional to wavelength; red RI < violet RI (dispersion is due to the different amounts different wavelength are bent)
o Fire,which is seen as rainbows and glints of color, is due to dispersion (a consequence of the placement of faces on the crown to take advantage of the prism effect).
Diamonds and their Synthesis
Diamond MicroChips Dot Com, Diamonds MicroChips Dot Com, http://diamond-microchips.com/
Review the light path in a correctly cut gem!
There are many alternative diamond cuts
A poorly cut stone is characterized by poorly chosen proportions (poor optimization of brilliance and fire or, worse still, leakage of light from the pavillion). Misplaced facets, extra facets, and problems at facet junctions are also characteristics that reduce the quality of "cut".
Ranking: VERY GOOD ... GOOD .... MEDIUM ... POOR
# (4) CARAT WEIGHT
Recall: 1 carat = 0.2 g, thus 5 carats=1g
For example, compare the size of a one point diamond to that of a 0.67 carat diamond
Just FYI: This site explains the GIA grading report used for diamonds, including information on desirable characteristics
Just for fun: Canadian approximate price lists and some very useful information and "straight talk" from Peter Mylnek.
Other issues: Treatment, simulants, synthetics
Diamonds and their Synthesis
Diamond MicroChips Dot Com, Diamonds MicroChips Dot Com, http://diamond-microchips.com/
(1) Diamond TREATMENTS:
* (a) filling of cracks
Surface cracks and cleavages reaching the surface: often with a glass-like material
Identification: optical microscope examination:
+ =greasy appearance
+ =flash effect
+ =bubbles
Problem: Filling does not always resist polishing and cleaning
* (b) drilling of inclusions
+ Drilling inclusions involves use of a laser.
Solutions can be poured into the resulting "hair-width" diameter hole to bleach colored inclusions.
* (c) irradiation
Irradiation is used to change the color of the diamond. A common color produced by irradiation is green.
Early attempts: beginning of 20th Century: diamonds exposed to radium - the problem was that the diamonds remained radioactive!! However, modern irradiation treatments do not produce radioctive stones.
Diamonds and their Synthesis
Diamond MicroChips Dot Com, Diamonds MicroChips Dot Com, http://diamond-microchips.com/
Irradiation involves the use of devices such as:
o (1) linear accelerators
o (2) gamma ray facilities
o (3) nuclear reactors
Detection of irradiation treatment:
Electron irradiation only changes the surface of the stone. Thus, it produces a concentration of color where the gemstone is thin. For example, electron irradiation produces a color concentration at the culet or keel line of the faceted gem
(2) Diamond SIMULANTS
Simulants - simulate the appearance of diamond
The distinction between a synthetic diamond (man-made diamond consisting of carbon atoms arranged in the typical diamond structure) and a diamond simulant (not a carbon compound with the diamond structure) is VERY important!!
Diamonds and their Synthesis
Diamond MicroChips Dot Com, Diamonds MicroChips Dot Com, http://diamond-microchips.com/
In order of increasing R.I., the most common simulants are:
1. YAG = yttrium aluminum garnet
2. GGG = gadolinium gallium garnet
3. CZ = cubic zirconia
4. Strontium titanate
5. diamond.
This rhyme can be used to memorize the common diamond simulants in the above order:
You go crazy staring at diamonds.
Again: Diamonds Simulants (look alikes) differ from synthetics (synthesized by humans!) !!!!
Simulants are distinguished from diamonds using measurement or observation of various properties, such as:
o R.I.
o "Read through effect"
o Dispersion
o Hardness
o Specific Gravity
o Reflection pattern
o Shadow patterns
Diamonds and their Synthesis
Diamond MicroChips Dot Com, Diamonds MicroChips Dot Com, http://diamond-microchips.com/
Note: not all diamond simulants have been around for the same length (lenght) of time!
(3) SYNTHESIS (Details on gem synthesis)
Synthetic diamonds are often yellowish in color (rarely used for gem purposes, more commonly used as diamond grit for industrial purposes. Modern synthesis of thin film diamond has other industrial applications).
A 5 mm diamond (0.5 carat) takes over a week to grow. Synthesis requires:
* high pressure
* high temperature
* a special apparatus
Diamonds and their Synthesis
Diamond MicroChips Dot Com, Diamonds MicroChips Dot Com, http://diamond-microchips.com/
Synthetic diamonds can sometimes be distinguished from natural diamonds by the presence of flux inclusions
Internet ref:
http://www.eureka.findlay.co.uk/eureka_editorial/news_reference/N-Diamond.htm
A sparkler for electronics
Tom Shelley reports on power components based on diamond which are getting closer to commercialisation and why they are even better than anticipated
Despite predictions that they could never be made, diamond power devices have bucked the doubters by reached the prototype stage. With an eye to the future, power semiconductors based on this diamond technology are expected to save more than 6,000MW of electrical power capacity in Japan alone with even greater savings envisioned in Europe. The first prototypes are based on very high purity, synthetic single-crystal diamond just 4mm across and 0.5mm thick. It is a well known and established fact that diamond holds great promise as a semiconductor substrate because of its very high thermal conductivity, five times that of copper; a breakdown field 30 times that of silicon; hole and electron mobilities several times better than silicon; and its intrinsic radiation hardness. However, nitrogen, the most common impurity in diamond, acts as an unusable deep (1.7eV) donor {{EXPLAIN - we're not all metallurgists}} and, at an IEE seminar on 'Advances in Carbon Electronics', doubts were expressed that the technical barriers facing those involved in the formulation of device-grade synthetic diamond substrates would ever be breached. It must, therefore, have given Daniel Twitchen, of De Beers Industrial Diamonds, now renamed Element Six, exceptional pleasure to announce the successful demonstration of prototype devices at the same event. The team, based at Ascot, has for some time, been producing impressive synthetic diamond windows, up to 100mm across, for high-power microwave and laser sources. The current development involves growing a single crystal from a seed in a hydrogen-methane microwave-heated plasma, at more than 2,000°C. After synthesis, the epitaxial overlayers are separated from the substrate by a laser, and doping with boron from diborane creates the semiconductor properties. The end result being very efficient diodes able to block up to 2.5kV. The aim of the programme, being undertaken in conjunction with ABB, is to produce diodes capable of passing or blocking 100A at 20kV. Commercially available devices based on diamond substrates include ultra violet sensors manufactured by Richard Jackman and his colleagues in the Diamond Electronics Group based at University College, London (UCL). The large band gap that hinders diamond's use as a conventional semiconductor is put to use here as only photons of ultraviolet wavelength are sufficiently energetic to make the surface hydrogenated material photoconduct. The UCL sensors use lower cost polycrystalline material, but the interdigitated grid of gold electrodes are printed sufficiently close together that, in most cases, only single crystallites bridge the gaps, making the material effectively single crystalline. As commercial devices come to market, we can expect more and more technical 'tricks' being employed to make good use of this amazing electronic material.
Internet Refurl: http://csdl.computer.org/comp/proceedings/vlsid/1995/6905/00/69050194abs.htm
8th International Conference on VLSI Design
January 04 - 07, 1995
New Delhi, India
p. 194 CVD-diamond substrates for multi-chip modules (MCMs)
H.A. Naseem, A.P. Malshe, R.A. Beera, M.S. Haque, W.D. Brown, L.W. Schaper, High Density Electron. Center, Arkansas Univ., Fayetteville, AR, USA
Diamond, the best thermal conductor known, is the ultimate choice as a substrate for three dimensional (3-D) multichip modules (MCMs) in the next generation compact, high power and high speed computers. It has only recently become available as a large area free-standing substrate fabricated using various chemical vapor deposition (CVD) techniques. There are several challenges and technological hurdles which must be resolved before diamond based MCMs becomes a reality. At HiDEC, University of Arkansas, we are actively involved in 1) designing diamond substrate based MCMs, 2) synthesis of diamond thin films and substrates, 3) polishing and planarizing diamond substrates, 4) laser drilling of via holes in diamond and, 5) metallization and dielectric coatings on diamond substrates for multi-layer interconnects (MLI). This paper presents a critical review of novel technologies that have been/are being developed at HiDEC for the fabrication of diamond based MCMs.
Index Terms- multichip modules; diamond; substrates; polishing; laser beam machining; metallisation; CVD coatings; elemental semiconductors; chemical vapour deposition; CVD-diamond substrates; multichip modules; 3D MCM; chemical vapor deposition; diamond thin films; polishing; planarization; laser drilling; via holes; metallization; dielectric coatings; multilayer interconnects; fabrication; C
Diamond Properties: Thermal Conductivity>br>
One of many remarkable properties of diamond is its uncompeted thermal conductivity. In contrast to metals, where conduction electrons are responsible for the high thermal conductivity, heat is conducted in electrical insulators by lattice vibrations. With a sound velocity of 17500 m/s, diamond is the material with the highest Debye temperature (2220 K), exceeding that of most other insulating materials by an order of magnitude and leading to the highest thermal conductivity of any material at room temperature (20-25W/cmK), exceeding that of copper by a factor of five.
Thermal conductivity of CVD diamond vs. temperature. For comparison, the thermal conductivity of copper is shown in red. Large area CVD diamond films have been proposed for many applications
CVD Diamond thermal management applications, though the first thermal conductivity measurements in the late 80s were not very promising. In recent years, however, the quality of CVD diamond improved dramatically, and large area CVD diamond plates with thermal conductivities around 20 W/cmK became available. Today, CVD diamond is used for various thermal management applications such as submounts for integrated circuits and heat spreaders for high power laser diodes. Mapping of the thermal conductivity CVD Diamond: Processing Laser cutting Polishing Metallization
CVD Diamond Laser cutting Laser cutting of CVD diamondDue to the extreme hardness of diamond a mechanical cutting or sawing of the diamond wafers is not possible. For that reason a Q-switched Nd: YAG laser is applied for cutting them into desired shapes. Polishing After deposition, the coarse grained films are ground and polished to the desired thickness. For this purpose a high speed lapping machine capable of treating three samples simultaneously has been developed. Diamond wafers with up to 4" in diameter can be polished.
CVD Diamond Rms roughness values as low as 20 • can be achieved under optimized conditions. Laser interferogram of a polished 2" diam. diamond disk (at 633 nm). The appearance of only one interference fringe demonstrates the perfect surface flatness
CVD Diamond Metallization For the preparation of diamond heat-spreaders the metallization is of central importance. Various metallization schemes consisting of several metal layers have been developed. Each layer acts either as adhesion layer, diffusion barrier, or as surface layer improving the wetting behaviour of the solder. Thick gold layers are used as electrical conductors for high current densities. Custom specific metallization schemes - for example metallized heat-spreaders with electrical isolation between the top and the bottom metallization - have been developed. Furthermore patterned metallizations prepared by photolithography are available.
CVD Diamond CVD Diamond: Optical Properties Optical transmission Applications The excellent optical properties of diamond have been known for a long time. However, optical applications require extended discs or thin coatings not provided by natural diamond crystals. With the development of CVD techniques the situation has changed completely. Broadband transparency Diamond is transparent from the UV (230 nm) to the far infrared. Only minor absorption bands resulting from two phonon absorption exist between 2.5 and 6 nm. Hence diamond is an ideal material for multispectral optical applications. Wide band gap No thermal generation of charge carriers at elevated temperatures, hence no "thermal run away" as in the case of Germanium under laser irradiation. Furthermore, diamond does not become nonlinear at high radiation intensities. High thermal conductivity Absorbed energy is quickly dissipated to the edges of a diamond window where it can be removed by appropriate heat sinks and cooling techniques. Mechanical and chemical stability Diamond is extremely hard, wear resistant and chemically inert. It is an ideal material for hostile, highly erosive atmospheres.
CVD Diamond Optical transmission spectrum of CVD diamond CVD Diamond: Applications Optical Applications Thermal Applications Radiation Windows Applications
CVD Diamond Optical Windows for high-power CO2 lasers The broad-band optical transparency, high thermal conductivity and hardness make diamond an ideal choice for highly demanding window applications such as high-power IR laser windows, high-power microwave windows and durable windows for aggressive environments Thermal ApplicationsCVD diamond heat-spreadersDue to the combination of excellent thermal conductivity and high electrical resistivity CVD diamond is getting more and more attractive for various thermal management applications, including diamond heat-spreaders for the cooling of high-power electronic devices (laser diodes) diamond submounts for flip-chip bonding of semiconductor
CVD Diamond circuits, direct deposition of thin diamond films on integrated circuits. Further Applications Substrates for Surface Acoustic Wave (SAW) Devices X-ray windows, lithography masks Cutting tools Wear resistant coatings Temperature and pressure sensors Cold electron emitters Detectors: particle and UV radiation detection
Internet ref url: http://www.cvd-diamond.com/tfdi/frames_e.htm and others.
Due to its combination of unique physical properties diamond is an outstanding material. Besides its unrivaled hardness diamond exhibits ultrabroadband transparancy ranging from deep UV to the microwave regime, and a thermal conductivity at room temperature which is higher than that of any other material. The excellent mechanical, thermal, optical and insulating properties of diamond became accessible through the advent of low pressure Chemical Vapour Deposition (CVD) techniques which allow diamond in the form of extended films and free-standing wafers to be fabricated.
Fraunhofer IAF has grown large-area (2 to 6 inches in diameter) CVD diamond wafers with thickness beyond 2 mm applying its patented microwave plasma reactor technology. Presently, various ellipsoid plasma reactors with microwave power levels of 6, 8, 12 and 60 kW are used to prepare diamond wafers. Subsequent double-sided finishing is applied to achieve perfectly smooth and flat surfaces. Phase purity, surface profile, optical absorption, and heat conductivity are routinely characterized.
The application of diamond wafers e.g. as laser windows require extremely flat surfaces and low absorption coefficients; the preparation of diamond heat-spreaders involves several manufacturing steps such as grinding and polishing, laser cutting and metallization; incorporations of additional features such as temperature sensors and resistive heaters into the diamond surface give rise to „smart" diamond heat spreaders for precise device temperature control - meeting such requirement is a strength of Fraunhofer IAF.
Products: Fraunhofer has been working on a variety of CVD diamond products which take advantage of the amazing properties of this material.
We will consult you on CVD diamond utilization, should you want to do business with CVD diamond. We provide technology licensing and continuous support. You may also be served by characterized CVD diamond samples. We process CVD diamond wafers further to application-specific specimens. Larger diameters and thicknesses of CVD diamond wafers are the objectives of our further developments.
Your Advantage You may use complete CVD diamond wafers or want to develop your application-specific specimens with us - we guarantee rapid prototyping. We are capable of transforming sample specimen manufacturing to small volume production. Your exploitation of our long-standing experience on CVD diamond saves you time and costs.
Target Applications Laser windows for high-power CO2 lasers, Microwave transmitting windows for high-power gyrotrons and klystrons, Dielectric submounts for microwave and millimeter wave ICs, Heat-spreaders for high-power microelectronic circuits and diode lasers, Smart heat-spreaders, Highly refractive microoptics micro-optics.
CVD Diamond:
General Information
Chemical Vapor Deposition
Diamond has always been an outstanding and desirable material. With the invention of synthetic growth techniques at high pressures and temperatures in the fifties, it became technical material, especially for mechanical applications. However, it was the advent of low pressure deposition techniques that made accessible the excellent mechanical, thermal, optical and electronic properties. With these chemical vapour deposition (CVD) techniques diamond became available in the form of extended thin films and free-standing plates or windows. Doping during deposition could be realized, making
diamond a p-type semiconductor. With CVD-diamond a wealth of new applications opened up.
Deposition from the gas phase
The fundamental problem of diamond synthesis is the allotropic nature of carbon. Under ordinary conditions graphite, not diamond, is the thermodynamically stable crystalline phase of carbon. Hence, the main requirement of diamond CVD is to deposit carbon and simultaneously suppress the formation of graphitic sp2-bonds. This can be realized by establishing high concentrations of non-diamond carbon etchants such as atomic
hydrogen. Usually, those conditions are achieved by admixing large amounts of hydrogen to the process gas and by activating the gas either thermally or by a plasma.
Initial diamond nuclei formed on the substrate surface
Surface morphology of a polycrystalline diamond film
Hence, a common feature of all diamond CVD techniques is a gas-phase nonequilibrium, i.e. a high supersaturation of atomic hydrogen and of various hydrocarbon radicals. Typical deposition conditions are: 1 % methane in hydrogen as source gas, 700-1000°C deposition temperature and gas pressures in the range 30-300 Torr.
The various diamond CVD techniques differ mainly in the way of gas phase activation and dissociation. The most common techniques include a) thermally assisted CVD, usually realized by gas activation with a hot filament, b) microwave plasma assisted CVD, c) deposition in a combustion flame sustained e.g. by acetylene and oxygen, and d) arc jet CVD. Each of these techniques has its pros and cons. The distinguishing features are the deposition rate, the deposition area and the quality of the deposited diamond. The maximum growth rate reported so far amounts to almost 1 mm/h. However, those high growth rates are usually limited to very small deposition areas (« 1 cm2). In general there is an inverse relationship between film quality and growth rate. Optically transparent films with high thermal conductivities are usually deposited at rates not exceeding 10 µm/h, regardless of the deposition technique.The excellent optical properties of diamond have been known for a long time. However, optical applications require extended discs or thin coatings not provided by natural diamond crystals. With the development of CVD techniques the situation has changed completely.
CVD Diamond Wafers
CVD diamond is a pure and polycrystalline functional material having many excellent properties, for example, the greatest hardness, extremely high thermal conductivity in nature, excellent electrical resistivity and chemical stability of any acid and alkali erosion resistance, etc. Additionally, CVD diamond can be produced in shapes and sizes. And the mechanical properties of CVD diamond share some advantages of both single crystal diamond and PCD. The main products made of CVD diamond include CVD diamond precision bearing shoes and wear parts, CVD diamond wire die blanks, CVD diamond heat spreaders, CVD diamond dresser logs and dressing tools and CVD diamond cutting tools.
Main Properties
Hardness (Knoop) (8000~10000) kg/mm2
Thermal conductivity (5~14)W/cm.K (300K)
Density 3.5 g/cm3
Resistivity £¾1010¦¸.cm
Thermal expansion coefficient (1.0~2.0) x10-6¡æ-1
Specifications
Max area: ¦µ80, ¦µ120mm
Thickness: 0.3~2.0mm
Any other thicknesses and shapes are available upon request.
Superhard Materials Subject
Technological research and practice in the aspects of synthesizing diamond production technology by the belt-type press and complete sets of equipment were carried on in RISC for many years, and 25MN and 60 MN belt-type presses and superhigh pressure toolings winded with wires were successfully researched and developed. Synthetic diamond technology for the belt-type press of our country with our own intellectual property right has been developed. Adopted advanced technology for synthesizing saw blade grade diamonds, production on a large scale was put into effect by using home belt-type press for the first time. And various specifications and mesh sizes single crystal diamonds with high quality and PCD products can be produced according to the market¡¯s demand.
Depending on the key project on National Programme (863), DC plasma-HF CVD method different from growing technology for diamond thick film at home and abroad at present has been developed independently in RISC, which boots the depositing rate and homogeneity of the diamond film greatly and decreases the energy consumption at the same time. A series of technological achievements in the aspects of processing technologies for cutting, polishing and welding diamond film were achieved, and the project on ¡°Preparation of Diamond Film for Industry and Its Application Development¡± won the second National Scientific and Technological Progress award in 2002. Diamond films can be mass produced in RISC, and production lines for preparation of diamond film materials, PCD and PCBN processing have been set up. The products are widely used in the fields of cutters, wearing devices, high power semiconductor devices, large scale integrated circuits, optoelectronic devices, optical windows and advanced satellite communication, etc.
RISC is one of the earliest units to develop synthetic diamond tool products at home, took the lead in introducing advanced technologies and equipment from foreign countries, such as high power laser processing and welding equipment and equipment for water atomizing alloy powder. And it gained many new and practical patents from the state and state key new products certificates.
High power density microwave plasmas
Diamond deposition at high power densities has yielded more than one-of-magnitude improvement of the linear growth rates previously possible in similar reactors at lower power densities. In this new system, diamond deposition rates of up to 60 mg/hour have been demonstrated. Linear growth rates of 15micro meter/hour near the center of the sample have been measured. Figure 1 shows a cross-section of a diamond film grown at such rates. Note the columnar structure characteristic of high growth rate depositions. Figure 2 shows a top view of the films. Nicely faced material is obtained. At these high rates, thick free-standing films are possible within a few hours of deposition.
Figure 3 shows preferential alignment of the crystals along the [100] direction which is obtained under some deposition conditions. Preferential alignment of the facets can have applications for these CVD films in active electronics.
The thermal conductivity of diamond films samples grown at rates near 3micro meter m/hour was measured using two different techniques. The measurements yielded values of the thermal conductivity in the 10 to 20 W/cm-K range. This high thermal conductivity value makes such films ideal for heat sink applications. As an example, the Raman spectrum for one of these films is shown in Figure 4. The FWHM of the diamond line near 1332cm-1 was measured at 6cm-1. This value is close to the width for natural diamond (approximately 2 cm-1). Such narrow width lines are characteristic of high quality CVD diamond.
Its broad-band optical transparency, high thermal conductivity and hardness make diamond an ideal choice for many applications. Fraunhofer IAF masters the technology of depositing diamond on various substrates thus manufacturing coatings and free-standing diamond disks.
Contact:
Prof. Peter Koidl
Phone: +49 761/5159-350
Koidl@iaf.fraunhofer.de
Using microwave plasma CVD (chemical vapor deposition) large-area (2 to 6 inches in diameter) diamond disks with thicknesses up to 2 mm have been grown. The deposition is carried out in a plasma reactor having an ellipsoid cavity to generate very intense, spatially extended plasmas from a CH4/H2 gas mixture.
Presently, ellipsoid plasma reactors with 6 to 60 kW microwave power are used at Fraunhofer IAF, producing diamond wafers of high quality. After deposition, the coarse-grained layer is polished and the substrate removed. The diamond wafer is then laser-cut to shapes and dimensions required as optical windows or thermal heat spreaders. Our novel developments are diamond lenses and arrays of microlenses as well as diamond scalpels of various shapes and geometries.
http://www.whiteflash.com/knowledge/Q10046.aspx
There may soon come a day when your computer will have a sticker on it that says, "De Beers Inside," rather than "Intel Inside"—say, by 2010.
As microchips run faster, they get hotter. Conventional silicon chips burn out and then up once temperatures reach a certain point. To reach much higher speeds, future microchips will need to be able to conduct heat in ways that today's silicon components can't.
That's why diamonds have suddenly become the substance du jour in high-tech development labs all over the world. Diamond can take heat like no other substance.
The problem with developing diamond microchips is this: the cost of producing man-made, or lab-grown, diamond has always been prohibitive. But during the last decade, Russian scientists developed tabletop machines that could generate the heat and pressure needed to create man-made diamonds. Voila, synthetic diamonds costing as little as $100 in time, energy and materials could be manufactured in days and even hours, if all you wanted was melee.
In 1996, an ex-army general, Carter Clarke, started a company called Gemesis in Sarasota, Florida, that imported a dozen or so of these Russian diamond making machines and began growing synthetic gem fancy-yellow diamonds by the bushelful. Thankfully, they could be easily detected by trained gemologists. But, as any reader of Wired Magazine knows, they can fool the seasoned eyes of dealers.Now there is a second diamond growing company, Apollo Diamonds, based in Boston, producing white and yellow stones just as cheaply.So the question is no longer if the jewelry market will be flooded with synthetic gem-quality diamonds but when. And the answer is now. While developing a low-cost diamond microchip, diamond growers are offering gem-quality stones to jewelers as a revenue-producer. So far, few are nibbling. But that is bound to change.
Don't worry. Both companies put special microscopic inscriptions on stones revealing their maker's name as well as their lab origin. De Beers has developed special equipment for gemologists and jewelers to facilitate easy
identification of the man-mades. So there is relatively little danger of rip-off.
And don't forget that Gemesis and Apollo are working on developing affordable diamond chips that can replace silicon ones. That's where the big money is. Once they do, the threat of cheap synthetic diamonds will recede.
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From http://www.amnh.org/exhibitions/diamonds/squeeze.html
The device used by GE to synthesize diamond was termed a belt device because tungsten carbide rams were driven into a cavity contained by a doubly-tapered carbide cylinder, contained in turn by a steel jacket - termed a belt. Between the rams is a cylinder of graphite - a furnace - containing the material to be raised to high temperature and pressure. Around the furnace assembly and between the anvils and belt is a compressible material to contain the pressure and accept the deformation; it has traditionally been a natural clay called "pipestone clay" for its alternative use in tobacco pipes. A hydraulic press, capable of perhaps 50 tons, drives the rams into the belt cavity, amplifying the force at the interior to high pressure. An electrical current is passed between the rams and through the conductive graphite, which heats in response; the clay acts as a thermal insulator as well as a container for pressure.
From http://www.amnh.org/exhibitions/diamonds/heat.html
Hardness is not the only superlative property of diamond that makes it important in industry and technology--its extraordinary thermal conductivity, low-friction surface, and optical transparency put diamond into cutting-edge applications. Many new products, like compact electronic devices, windows for optical devices in demanding environments, and "no-wear" bearings, such as in the space shuttle, utilize diamond. For these applications, a synthetic form leads the way. This is CVD, so-named for the growth technique chemical vapor deposition.
Various products composed of or coated with CVD diamond. They include heat spreaders, cutting tools, windows, and a bearing identical to one used in the space shuttle.
At present the major commercial application for CVD diamond is in thermal management, where diamond heat-spreaders conduct byproduct heat away from a device. The material can be grown with a thermal conductivity close to that of the best natural and high-pressure synthetic diamonds used until now as heat spreaders. Thousands of suitable heat spreaders can be cut from a single wafer of CVD diamond, making for efficient use. A CVD diamond coating on an object can be polished to yield an extremely smooth diamond surface, ideal for high precision and low friction, such as is needed for precision bearings. CVD diamond wafers with high optical transparency are excellent for viewing a wide portion of the electromagnetic spectrum in environments with extreme temperature, corrosiveness, or radiation.
Cruise missiles and smart bombs utilize infrared detectors to seek their targets. Diamond windows can provide a wide band of transparency and resistance to abrasion and heat thereby improving the targeting of such devices.
ref url: http://www.minelinks.com/alluvial/diamonds4.html
DIAMOND
For comparison, the following values of the refractive indices of a particular glass may be given:
Red light 1.524312
Yellow 1.527982
Green 1.531372
Violet 1.544684
The dispersion coefficient is here less than half as great as that of diamond.
1.544684 - 1.524312 = 0.020372,
Under the same conditions, the prism of diamond will produce a spectrum over twice as long as a spectrum produced by a prism of glass.
Anomalous double refraction
Diamond, being crystal listed in the cubic system, should be singly refracting, that is, isotropic. This, however, is only strictly true for such stones as are perfectly colorless, or of a yellowish color, and are quite free from enclosures of foreign matter, cracks, and other flaws. Such faultless stones when rotated in the dark field of the polarized light remain dark. As previously mentioned, the stone under examination should be immersed in methylene iodide, so as to diminish total reflection as far as possible.
Deeply colored stones, and those disfigured by cracks, enclosures, or other faults, when placed in the dark field of the polarized light, allow the passage of light to the eye, but as a rule, to only a small extent. They have, under these circumstances, a grayish appearance, brilliant polarization colors being rarely seen. The feeble double refraction possessed by such stones is not an essential character of the substance of the diamond itself, but is due to disturbing influences; hence it is distinguished as anomalous double refraction. During its rotation in the polarized light it rarely happens that such a stone is uniformly dark or uniformly light over its whole surface; as a rule, certain areas are dark while others are light, and vice versa. Frequently certain regularly bounded areas or fields behave in a similar manner during rotation, while adjacent fields behave differently. In most cases, however, the areas showing these differences in behavior have no definite arrangement relative to each other, and areas showing a feeble double refraction are often enclosed in areas, which are perfectly isotropic.
The doubly refracting portions of the stone usually surround enclosures or cracks, and it is in the immediate vicinity of these that double refraction is strongest and the polarization colors most brilliant. As the distance from a flaw of this kind increases the double refraction becomes feebler, and at a certain distance disappears. Sometimes a black cross, the arms of which consist of two dark brushes, is seen when a stone is examined in the polarized light the arms of the cross are mutually perpendicular and their point of intersection coincides with an enclosure in the diamond. It is clear that such an appearance is due to a strain in the diamond brought about by the presence of the enclosure, and that the strain will be less in portions further removed from the enclosure.
Although the anomalous double refraction of diamond is, as rule, but feeble, stones exist in which it is comparatively strong, and which show much brighter polarization colors. This is the case in the "smoky stones" of South Africa, which, because of the great internal strain in their substance, have a tendency to fall to powder for no apparent reason. A parallel case is that of the drops of glass known as" Prince Rupert's drops," which also show strong double refraction as a consequence of internal strain.
There is never the slightest danger of confusing anomalous with true double refraction, for a mineral with true double refraction, such for example as quartz, colorless sapphire or topaz, will appear much more brilliantly illuminated when examined in the polarized light, and, moreover, will be uniformly light or uniformly dark over its whole surface.
Color
Diamond is often regarded as the type of what a perfectly clear, colorless, and transparent stone should be. It can by no means, however, be always so regarded, since cloudy and opaque diamonds are actually more common than those, which are clear and transparent, while very great variety in color is found in this mineral. A great number of diamonds are indeed perfectly colorless, and correspond strictly to the popular conception of the stone; this number is, however, only one-fourth of the total number of diamonds found; another quarter show a very light shade of color, while the remainder, at least one-half of the total, are more or less deeply colored.
Perfectly colorless diamonds are, at the same time, freest from impurity. Absolutely pure carbon, crystallized in the form of diamond, shows no trace of color whatever, and stones of this purity are naturally highly prized. A peculiar steel-blue appearance is sometimes observed in stones, which combine absence of color with perfect transparency. With the exception of a few especially beautifully colored stones of great rarity, these blue-ni1e diamonds are the most highly prized of all; they are not of great rarity in India and Brazil, but occur in South Africa with far less frequency.
Any coloring matter intermixed with the substance of a diamond imparts its color to the stone, the tone of which will he faint when the pigment is present in small amount and deeper when it is present in greater amount. In all cases the amount of coloring matter relative to the mass of the stone is extremely small.
Investigations into the precise nature of the various coloring matters present in diamonds have seldom been undertaken on account of their difficulty and expense. There can be no doubt, however, that the coloring matter of many diamonds is of an organic nature, possibly some one or other of the hydrocarbons; in other cases the pigment is probably inorganic material in an extremely fine state of division. We have already seen that colored diamonds contain a small amount of ferruginous material, which remains behind as an incombustible ash after the diamond is burnt away, and that with colorless diamonds this is not the case. There seems sufficient grounds here for the inference that in such cases the color of the stone is due to the inorganic, incombustible, enclosed material, especially as the color is neither altered nor destroyed after exposure to high temperature, which would he the case were it organic in nature. In the few recorded cases in which a change of color has to the organic nature of the coloring matter.
The coloring of many diamonds is so faint that an unpracticed observer, unless he is able to compare such a stone with an absolutely colorless diamond or to place it against a background of pure white, will fail to recognize that the stone is colored at all. The practiced eye of the diamond merchant, however, needs no such assistance in recognizing the most faintly colored stones. Such stones are rather lower in value than absolutely colorless specimens of the same clearness and transparency, but the difference in price is not very considerable. The shades of color, which appear most frequently, are light yellow, gray, and green. A faintly yellow diamond is not observable as such in any artificial illumination other than the electric light, and then appears to be a colorless stone. Diamonds of a faint bluish tinge are known, but are much less common.
As mentioned above, diamonds showing a pronounced coloration constitute about one-half of the total output. Almost all the colors of the mineral kingdom may be represented in numerous and varied tints, so that the suite of colors of the diamond is very extensive. A magnificent collection of differently colored diamonds, the most beautiful and the richest in existence, was preserved in the treasury of the royal palace at Vienna. Helmreichen, who spent many years in Brazil, and was so enabled to make the series very complete, brought it together. The color, which occurs most frequently in diamonds, is yellow, in various shades, such as citron-yellow, wine-yellow, brass-yellow, ochre-yellow, and honey-yellow, but golden-yellow has not as yet been observed. Most of the Cape diamonds are colored with one or other of these tints of yellow. After yellow, green is the most commonly occurring color, especially in Brazilian diamonds. Oil-green or yellowish-green is seen most frequently, then pale green, leek-green, asparagus-green, pistachio-green, olive-green, emerald-green, bluish-green and grayish-green. Brown diamonds are also common at all localities; the different shades are light brown, coffee-brown, clove-brown, and reddish-brown. Shades of gray, such as pale gray, ash-gray, smoke-gray, are not rare. Black diamonds in well-formed crystals are unusual. The different shades of red, a color, which is rarely met with in diamonds, are lilac-red, rose-red, peachblossom-red, cherry-red, and hyacinth-red. Blue in its two shades, dark blue and pale sapphire-blue, is the rarest of all colors to be met with in diamonds.
The coloring of diamonds is seldom intense, pale colors being much more usual than deeper shades. Diamonds which combine great depth and beauty of color, with perfect transparency, are objects of unsurpassable beauty; for, in addition to their fine color, they possess the wonderful luster and brilliant play of prismatic colors peculiar to the diamond, so that other finely-colored stones, such as ruby and sapphire, are not to be compared with them. Only a few stones of this description are in existence; they are among the most highly prized of costly gems.
Of such deeply colored and perfectly transparent diamonds, bright or deep yellow specimens are, since the discovery of the South African diamond fields, the least rarely met with. The largest of these yellow Cape diamonds is a beautiful orange-yellow brilliant, weighing 125 3/8 carats, and was in the possession of Tiffany and Co., the New York firm of jewelers. A few fine yellow stones dating back to ancient times were preserved in the "Green Vaults" at Dresden.
Diamonds of a fine green color are distinctly rare, only a few examples being known; the same may be said of red diamonds and, even more emphatically, of blue diamonds. The most beautiful green diamond known is a transparent brilliant weighing 48 carats, which was preserved in the "Green Vaults" at Dresden; it will be again mentioned in the section devoted to famous diamonds. Tschudi mentions two beautiful specimens from Brazil, one of an emerald-green and the other of a sea-green color, while the existence of other Brazilian stones with a color very similar to that of the yellowish-green of uranium glass, but inclining more to yellow, is mentioned by Boutan.
Red stones are rare. The ten-carat ruby-red stone, which belonged to Czar Paul I. of Russia, and which is said to be still preserved with the Russian crown jewels, is often mentioned as an example of a red diamond; nothing more definite concerning it is, however, known. A better-authenticated example is the "Red Haiphen" diamond, a ruby-red brilliant weighing one carat, while recently Streeter has reported the discovery of a beautiful red stone in Borneo, and its sale in Paris. Several examples of beautifully transparent rose-red diamonds are known; such, for instance, as that of the fifteen-carat stone belonging to the Prince of Riccia, a few smaller specimens in the treasury at Dresden, and a thirty-two-carat stone, the most beautiful rose-red known, in the treasury of Vienna. A rose-colored brilliant, called the "Fleur de Pecher," is (was) among the French crown jewels, and Tschudi mentions a peachblossom-red stone from the Rio do Bagagem, in Minas Geraes, Brazil;
Blue diamonds are the most rare of all. A magnificent blue brilliant of 44 1/4 carats, the "pearl of colored diamonds," was formerly in the possession of Mr. Hope, a London banker. It is probably a portion of Tavernier's blue diamond of 67 1/8 carats, stolen in 1792 with the French crown jewels. A small diamond of a deep blue color, and a pale blue one of forty carats, were preserved in the Munich treasury.
Black diamonds perhaps deserve a brief mention. Crystals of a uniform black color have been found in Borneo, and also very rarely in South Africa. The opacity of such stones, combined with their high degree of luster, almost metallic in its character, render them, when cut, of peculiar beauty, and well suited for use in mourning jewelry. These crystals of black diamond must not be confused with the black carbonado of Brazil, to be described later. A few brown stones of a delicate and beautiful coffee shade are known; these also come from Brazil.
As is most always the case with precious stones and other minerals, the color of which is due to enclosed foreign matter in an extremely fine state of division, so also in the diamond the distribution of the coloring matter is not always perfectly uniform throughout its whole mass. The pigment may be collected or accumulated in isolated patches, while the rest of the stone is either colorless or less deeply colored. In numerous cases, only the thin surface layer of the crystal is colored, the interior of the stone being colorless; this occurs often in Brazilian stones, especially those from the Rio Pardo, in the Diamantina district. When the outer layer, which is often pale green in color, is removed in the process of cutting, a perfectly colorless stone is obtained. Tschudi mentions a fine emerald-green brilliant from Brazil, which before cutting had a sooty black appearance; another specimen of similar appearance retained its black color almost entirely after cutting, a few facets only appearing white.
Not infrequently the bulk of a rough diamond is colorless, the edges and corners only being colored; many Brazilian stones are of this description, as well as specimens from South Africa, including some of the "smoky stones" already mentioned. In these the deep smoky-gray color is sometimes confined to the corners of the stone, the interior being faintly colored or entirely colorless; a stone so colored is described as a "glassy stone with smoky corners." Diamonds in which these conditions are reversed also occur, the edges and corners being colorless, and the central portion colored.
DIAMOND
Sometimes, though rarely, a stone shows two differently colored portions; the two portions of one mentioned by Mawe were colored respectively yellow and blue. Stones showing a number of differently colored sectors, sharply separated from each other, and radiating from a central point, are also of rare occurrence. Thus smoke-grey and colorless rays may have a regular star like arrangement, or may form a figure like the club of playing cards, on the faces of the octahedron.
Of interest is the fact that diamond sometimes shows a play of colours like that of precious opal. Des Cloizeaux mentioned a few such stones, which differed from opal in this respect only in that the colours were less brilliant. Pale blue and yellow stones have been reported by Mawe to show a somewhat similar appearance.
The color of diamonds is by no means in every case unchanging and unalterable. Some stones are bleached by sunlight; thus a red diamond on exposure to sunlight is reported to have gradually lost its color and become white. A diamond in the possession of the Parisian jeweler, Halphen, undergoes a peculiar change in color on exposure to heat. This stone, which is of a faint brownish color and weighs four grams (about twenty carats), assumes in the fire a beautiful rose-red color. If kept in darkness this color is retained for about ten days, after which it returns to its original brownish color; should the stone be exposed to diffuse daylight, or to the direct rays of the sun, the change to the original color is much more rapid. The change to rose-red can be produced at will by again exposing the stone to the action of heat. Could means be devised for retaining the rose-red color of the stone, the possessor would benefit to the extent of many thousand francs, since it is valued when brown at 60,000 francs, and when rose-red at from 150,000 to 200,000 francs. Halphen has also seen a diamond which when rubbed assumed a rose-red color:
This color, however, was lost again almost immediately.
The color of diamonds is in some cases affected by exposure to a high temperature. According to Des Cloizeaux, pale green diamonds, after being heated in the ox-hydrogen flame, became light yellow; brown crystals under the same conditions become grayish. Baumhauer also witnessed the color of one diamond change from green to yellow, and of another from dark green to violet, under the influence of a high temperature. Wöhler caused green diamonds to assume a brown color by heating them; hut found that brown stones remained unaltered in color. Yellow diamonds, especially those from the Cape, retain their color at the highest temperatures.
It has already been mentioned that very faintly colored stones command a somewhat lower price than do those, which are perfectly colorless. Hence many attempts have been made to transform faintly colored stones into the more valuable colorless stones. This is readily effected in those Brazilian diamonds, which have a colorless central portion surrounded by a colored external layer of no great thickness. The outer colored layer is in these cases simply burnt away by heating the stone in a crucible with a little saltpeter. The operation is very brief, the colored external layer disappearing in one or two seconds. This device involves no actual change of color, but is simply a removal of the colored portions, which could have been effected just as well by the more lengthy process of grinding.
Attempts have been made, however, to decolorize diamonds in which the undesirable pigment is distributed through the substance of the whole stone. Probably the first to make experiments in this direction was the Emperor Rudolph II.; according to the report of his gem expert, Boetius de Boot, the Emperor was acquainted with a method by which every diamond could be decolorized, and rendered perfectly colorless. This important secret, however, died with its possessor. At a later date the Parisian jeweler, Barbot, claimed to be able, by the employment of chemical means and a high temperature, to decolorize green, red, and yellow stones, while dark yellow, brown, and black stones only slightly lost their color. Barbot's method was also preserved as a secret, so that it is impossible to put his assertion to the test; it is probable, however, that he did not possess the power to which he laid claim, in spite of the fact that he described himself on the title page of one of his books as "Inventeur du procede de decoloration du diamant." Our present knowledge of the constituents of diamond pigments makes us unwilling to believe too readily in the possibility of their complete destruction; at all events, no method is at present known which is effectual in all cases.
Although it is impossible actually to destroy the color of yellow diamonds, such as now so often come into the market, it is easy to disguise their yellow tint and make them appear colorless. This device has often been practiced for fraudulent purposes, and was successfully carried out in Paris a few years ago. The yellow stone is placed in a violet liquid, such as the dilute solution of potassium permanganate used for disinfecting purposes. On being taken out and allowed to dry the stone becomes coated with a thin film of the violet substance. The combined effect of yellow and violet colours in certain proportions is to produce in the eye the sensation of white light; hence, when the violet layer is of a certain thickness, the stone will have the appearance of being perfectly colorless. Should it still appear yellow after the first trial, it may be immersed a second or third time, while if the violet color is too deep, some of it may be washed off. Instead of a solution of potassium permanganate violet ink may be used for this purpose. A stone treated in this way will, of course, remain apparently colorless only so long as the violet coating remains intact; directly this is rubbed off, which readily happens, the yellow color of the stone becomes apparent. A more permanent coating is said, however to have been recently devised for this purpose. The methods by which yellow stones can be made to appear
colorless are very old; ultramarine is supposed to have been used by the ancient inhabitants of India for this purpose.
According to the investigations of Petzholdt, which are confirmed by every diamond cutter, the color of diamond powder or dust varies from gray to black, and is darker the finer its state of division.
Phosphorescence
Many erroneous statements have been made with regard to the phosphorescence of diamond. Thus it has been stated that diamond phosphoresces in darkness after exposure to the direct rays of the sun, the phosphorescence being specially marked after exposure to blue light, and less so after exposure to red light. It is even said that after being screened by a board or paper from the direct rays of the sun, so that the stone is exposed to diffuse daylight only, it will be seen to glow brightly when placed in darkness.
Exact researches, however, have proved that only very few diamonds phosphoresce after exposure to sunlight, and that neither the direct rays of the sun nor intense artificial light cause phosphorescence in the majority of stones. Streeter reports that a yellow stone of 115 carats, after exposure to lime-light lit up a dark room; and Edwards describes a water-clear diamond of 92 carats, which after one hour's exposure to electric light emitted in a dark room a light which lasted for twenty minutes, and was so strong that a sheet of white paper placed near the stone could be distinctly seen. Of 150 diamonds of various forms, sizes and qualities examined by Kunz, only three showed the phenomenon of phosphorescence after exposure to the light of the electric arc.
Although exposure to light has in diamond so small an effect in exciting phosphorescence, rubbing the stone easily produces the phenomenon. Kunz observed that all the diamonds he examined, without exception, became self-luminous after being rubbed on wood, leather, woolen or other material. Some stones needed only to be drawn once across the substance, especially if it were of wool, to render them self-luminous; the most marked phosphorescence was, however, developed in stones by rubbing on wood against the grain. According to other statements, rubbing on metals (iron, steel, copper) is effective.
X-rays induce phosphorescence in most of diamonds, if not all. This property is used to separate diamonds from concentrate. The compressed air powered x-ray machines replaced old grease tables.
Whether diamonds are capable, as a rule, of giving out light after being raised to a temperature below red heat is doubtful, but some specimens, which are unaffected by sunlight and remain quite dark, are induced to glow by exposure to electric sparks. But here, as in all cases, the phosphorescence can be produced only when the stone has not previously been exposed to a strong heat.
The light given out by a phosphorescing diamond is in almost all cases feeble, and much less intense than that emitted by many other phosphorescent substances. The light, which is usually yellow in color, but may under certain circumstances be blue, green, or red, is strongest when induced by electric sparking. Remarkable observations have been made on the appearance of different faces of a phosphorescing crystal of diamond. Dessaignes (1809) stated that a diamond after exposure to the sun's rays emitted light from the cube faces, but not from the octahedral faces, which remained quite dark. Maskelyne described a diamond crystal, which emitted a beautiful apricot-colored light from the cube faces, a bright yellow from the faces of the rhombic dodecahedron, and a yellow light of another shade from the octahedral faces.
All these appearances are, as a rule, of brief duration. A case is, however, recorded of a diamond, which continued to phosphoresce for an hour after the removal of the exciting cause.
The phosphorescence of diamond is said to have been first observed in 1663 by the famous English physicist Robert Boyle.
ELECTRICAL AND THERMAL CHARACTERS.
A diamond, whether rough or cut, becomes positively electrified on rubbing; the charge so acquired is quickly lost, never being retained more than half an hour. In contrast to graphite, the other crystallized modification of carbon, which is a good conductor of electricity, the conductivity of diamond is so inappreciable that the stone ranks as a nonconductor.
Diamond being a good conductor of heat appears cold to the touch, and by this means can be distinguished from other substances, as already explained.
Diamond is unique because of its wide range of extreme properties, it's the hardest known material, has the lowest coefficient of thermal expansion, ischemically inert, wear resistant, has very low friction, good light transmitting properties from the ultra-violet (uv) into the far infrared (ir), and diamond currently finds use in many diverse applications including potential applications for diamond as the ultimate technological and engineering substance, also for the industrial diamond group and industrial diamonds arts and sciences expansion evolution, it exhibits extreme mechanical hardness (~91 GPa), it is the strongest known material (1.2 x 1012 n/m2s),
lowest compressibility (8.3 x 10-13 m2/ N), Thermal expansion coefficient at room temperature (0.8 x 10-6 K) is comparable with that of invar, it has Wide optical transparency from the deep uv to the far ir region of the electromagnetic spectrum, it exibits excellent electrical insulator (room temperature resistivity is ~1016 Ω cm), diamond can be alloyed to alter its resistivity over the range 10-106 Ω per centimeter, then becoming a semiconductor with an extremely wide bad gap [5.4 ev], diamond microchips are Very resistant regarding chemical corrosion, diamond cpu's are biologically inert, they exhibit verylow to negative electron affinity,
Scientific interest in diamond is further increased by the very recent discovery that it is feasable to produce polycrystalline diamond films, and coatings, by a large variety of chemical vapour deposition (CVD) techniques such as using, as process gases like hydrocarbon gas, aka methane, in an excess of elemental hydrogen gas, economically feasable alternative to the current HPHT
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