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Diamond Transistor

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It still amazes me that the rare shiny rocks humanity has appreciated for thousands of years also turn out to have amazing properties even compared to the synthetic materials we are now capable of creating. It's still the hardest material we have measured. It is the best thermal conductor, even though it's an electrical insulator.

It is a very good thermal conductor, but not the best. At low temperatures, copper is better. At very low temperatures, helium is much better.

Superfluid helium's maximum thermal conductivity is roughly 100x diamond's maximum!

Neat! At around the temperature of liquid water, it's still about five times as good as copper.

So.

1. They can grow diamonds.

2. Diamonds are good for heat conduction in the liquid-water-temperature range.

3. Diamonds are good for electrical insulation.

Where are the full diamond water blocks for the water cooled RGB bling computers?!?

It's murderously hard to machine.

True.

I guess it is a matter of what shape is grown. For some reason I thought a flat plate being sublimated onto but I honestly don't know.

But if you can get a flat plate made from diamond then a clever design should be able to use that.

But never mind the practicality - as long as it doesn't leak - then marketing could have a field day...

>Superfluid helium's maximum thermal conductivity is roughly 100x diamond's maximum!

Never thought about this before. Would that mean that heat propagates much more quickly? Possibly even approaching the speed of sound of the material?

Slide 12. Pretty much yeah. https://indico.cern.ch/event/1541024/attachments/3055157/540...

You can kind of isolate the different vibrational modes and their corresponding energy transmission. "Phonons" are basically sound waves (the particle analogue), labeled in figure 2: https://www.nist.gov/system/files/documents/2019/07/12/dcs_2...

Thermal conductivity measures the heat flux given a temperature gradient. That is, how fast heat energy flows across a surface, given a certain temperature gradient across it.

It has nothing to do with the velocity of the heat carriers themselves (phonons, or charged particles).

E.g. phonons always travel at the speed of sound, in any material.

They make nice (and expensive) tweeters, too.

https://www.madisoundspeakerstore.com/diamond-dome-tweeters/...

I've thought about this at times. How convenient that things seem to work out that way! Though I wonder if it's more just a bias. All the very impressive things you can make from the abundant materials have already been made. Like, say, all of life?

Blue pigments used to be extremely rare and precious. Then some chemists found the infinite blue glitch.

Also the convert energy into aluminum glitch.

Can you elaborate? Sounds cool

Up until electricity abundance, aluminium was almost unknown to most as refining it requires lots of electricity. Aluminium ore is very abundant too but we didn't know what to do with it.

Prior to this process, aluminum basically didn’t exist naturally and was incredibly hard to refine from bauxite.

It’s wild how not long ago aluminum was an unbelievably rare, valuable metal, and now it’s ubiquitous and cheap.

The intense electricity requirement is also why recycling aluminum is not just an environmental activity: it’s a profitable one.

https://en.wikipedia.org/wiki/Hall%E2%80%93H%C3%A9roult_proc...

And the convert energy into fertilizer glitch.

Diamonds are crystals, like silicon Nothing wrong with liking shiny rocks, but they aren't that rare and we can generally produce them. Materials have properties. Understanding the properties generally gives us leverage to use them in our own benefit.

> even compared to the synthetic materials we are now capable of creating

Aren't like almost all commercially used diamonds these days synthetic as well? As far as I can tell, other than just for the sake of them being "natural" or for having weird impurities that add color to them (read as: subjectively better to some people), no one wants/needs natural ones anymore.

We can recreate lots of things, but almost always appreciate the true version better. It’s why it’s cooler to see the Mona Lisa than to see a poster print of it.

Why? As far as I can tell, other than just for the sake of the view being “natural” or having some weird color issues due to time and radiation and oxidization, nobody wants/needs the actual painting anymore.

Reason: because even when it’s identical or even inferior, the touch of nature is just… nice.

I think you just described the placebo effect!

Unfortunately, as much as I'd like to pick and choose when it effects me, I am a mere mortal, as are many I believe.

A painting has a 3 dimensional texture to the paint, while a poster is inevitably flat. Different paint compositions will also reflect light differently, while a poster won't.

So, yeah, having the real painting has additional value.

I wouldn't pay much for a painting anyway. I have several paintings and posters up on the walls, and they're interesting for a time, and then I just don't see them anymore. They're just part of the wall.

One thing that plebians will never appreciate about the true value of original, legitimate artwork is the ease with which one can use them to launder vast amounts of money

For some things maybe.

For gemstones, nah I really don't want blood diamonds.

To be clear, you acknowledge the natural version would be better, but the controversy and conflict surrounding it is what actually turns you off. This has no effect on my argument that people prefer real things.

Naturally, if you said “you can have the Mona Lisa but only if someone is murdered in the process”, reprints of it would be very popular.

>To be clear, you acknowledge the natural version would be better

No, not at all. I prefer the artificial ones. Any size you want at a much lower cost. No massive amounts of mining. The fact they don't cost some indigenous kids lives is a well earned bonus.

It is you with a strong attachment to the idea that natural is somehow better.

> Any size you want at a much lower cost

In this case, I'll have the five million carat please. What will that run? :)

Is “synthetic” the right word?

I thought they are “lab grown”.

(Synthetic implies non-real, when at a molecular level the lab grown are 100% real)

I think synthetic ~ synthesized in this context, as opposed to "not real".

Sense 4a1 here, not 4c: https://www.merriam-webster.com/dictionary/synthetic

Unrelated, but does anyone else find the adjacent (4b) definition of 'synthetic' to be unusually unusual, in a way few definitions in a dictionary are?

Without anything redacted, definition 4b is "devised, arranged, or fabricated for special situations to imitate or replace usual realities"?

Seems okay to me

I guess I just think of "synthetic grass", like AstroTurf and associate "synthetic" with non-real.

> It's still the hardest material we have measured.

Can't believe this statement hasn't caused other nerds to crawl out of their holes to correct it yet, so here I go: acshually...

We know about Lonsdaleite, which packs its structured in hexagons rather than the usual cubic forms of diamonds.

... too bad its natural occurance is always somewhat spoiled and it doesn't reach its full potential in nature in any meaningful size, as far as we could observe.

Lonsdaleite looks like it should be harder than diamond based on simulation data, but we haven't actually measured a piece of Lonsdaleite that is harder than diamond.

Asionometry video on the topic: Why Diamond Transistors Are So Hard (https://www.youtube.com/watch?v=NLmd5vL0zmk)

Asionometry is quite informative, and sprinkles in some humor as well. Great to watch for anyone interested in the silicon industry.

>single-crystal diamond wafer

Can you hear the sound of DeBeers' execs melting down? I intend to play it as a white noise while I sleep.

Their marketing works just as well to create the diamond market just as well as it does to make synthetic diamonds mean you don't really love her.

With women size matters. Having 0.1 carat natural stone doesn't give you automatically social status above the one with flawless 30 carat monocrystal.

There may be market for artisanaly doped synthetics by customer design or something.

Those opinions are results of advertising.

You ever watch a sitcom where a future mother-in-law comments on how big the diamond in the ring is? Next time she'll be disappointing it's synthetic, except they'll come up with a more negative term (artificial, fake, etc.).

DeBeers is already almost dead. Anglo American has been trying to sell it for two years, the latest attempt at around $1B for their 85% share.

Diamonds are incredibly useful,

And logical, now that we can produce them easily enough.

This, is one of many uses of the rocks.

And no, blog writers, it is not heralding "The Diamond Age".

Recommended reading: https://en.wikipedia.org/wiki/The_Diamond_Age

Way better to recommend reading the book instead of the Wikipedia page about the book.

I don't know... LLMs, drones, culture wars, nostalgia for monarchical rule - we're only really missing the replicators and nano-engineering at this point.

Yes and: I still think Stephensen's notion of phyles will prove the most prescient.

https://en.wikipedia.org/wiki/The_Diamond_Age

I'll save my "Minecraft had it right all along" headline for a other day.

I still don't know how to even make a silicon transistor.

Make a Point Contact Transistor at home https://www.youtube.com/watch?v=vmotkjMSKnI

Amazing video, seen it long ago. Spoiler : you will need two diodes to make one.

Lucky me, I have exactly that many diodes.

You ever play that really old Zachtronics game where you have to design circuits at the silicon level? (KOHCTPYKTOP: Engineer of the People)

Give me an inverter and single logic gate and I can by myself recreate computing. Give me a silicon wafer and dopants and I no longer know what I am doing. The structure is 3D and also somewhat abstract and I fail to be able to maintain the mental state to understand it.

I don't understand my mental barrier. I get the abstract theory and rough physical concepts, but somehow I can't pull features out of a micrograph like Ken Shirriff can.

Oh I'm fine with designing logic circuits with transistors. I just can't manufacture even a single transistor.

Is there any new information here? They've been working on this for years and their last news post was almost a year ago. Is there progress? Is it viable yet?

I'm seeing more Silicon Carbide and Gallium nitride transistors in shipping products over the last ten years. With the latter a lot over the last 5 years.

I've only been hearing about diamond transistors for the last 30 years.

We know that a certain shiny rock consortium has done everything it could to slow down the development of synthetic diamond manufacturing. Maybe things will change when we can have research without a handbrake.

A bit more infos on DF linkedin page, see https://www.linkedin.com/company/diamond-foundry/posts

Forget the transistor for now: that's many years/decades away.

Much more likely to actually get to market is diamond as the heat dissipating substrate.

Why do people still think they need to mess with scrolling on their websites?

I know; at least very little else breaks on the site if you just kill scripts in ublock origin.

Normally, I am the first to complain about broken websites, but it looks fine for me on Firefox on a laptop. Scrolling works normal using up-down arrow keys and dragging on the side scrollbar. There is an unnecessary effect with the 3D diagram, but it doesn't interfere with the site. How are you viewing it?

i think they mean the sort of "inertial" scrolling that the site imposes

hmm, I'm not seeing anything that can be described as "inertia". Not on chromium either. Both of these are on a laptop with dragging the side scrollbars and using the up/down arrows on the keyboard.

Is this something that is related to a touch screen? I'm not using a touch screen.

I'm on a non-touchscreen mac, on firefox with smooth scrolling turned off, and have LinearMouse installed. I tried both trackpad scrolling and mousewheel scrolling. The weird "smooth" scrolling of this website is very jarring to me, and makes it take significantly longer to scroll to where I want to, since the responsiveness went from ~instant to ~.5s and I keep on overshooting.

try using a mouse or trackpad, they only seem to intercept pointer input. i also don't get affected when dragging the scrollbar or using the arrow keys.

Because it's their website, not yours?

So... how long does the hydrogen gas layer last before it all seeps out?

I believe these are hydrogen atoms covalently bonded to the carbon atoms on the surface of the diamond.

The hydrogen is not a gas.

Anyone else reminded of that old Crighton book, Congo?

I was reminded of https://en.wikipedia.org/wiki/The_Diamond_Age

Isn't the power consumption needed to create pure/no-blemish lab diamonds so great, that this wouldn't be feasible to scale.

massive crushing pressure is not the only way to create diamond particles.

do you mind explaining more

Chemical Vapor Deposition (CVD)

Lab diamonds are used in huge quantities (ie. By the bucketful ) for making cutting tools like saws and drill bits.

I believe the main difficulty is making large and pure diamonds. Making small low purity diamonds is cheap and easy to scale.

That was ten years ago. Today, lab grown diamonds are cheaper than natural at any size or quality, which is why the diamond cartels are sh*tting little bricks that are almost as hard.

Sure, but big ones still are expensive compared to say sand or other hard materials.

This is not my field, but I'm...socialy adjacent? and my understanding is that we grow big crystals of silicon because that's the mature technology, but then there are multiple cutting & polishing steps that add to the cost.

We want small pieces of thin wafers, but we grow huge crystals and then slice them into wafers that we then have to cut up. With vapor deposition diamond you can remove a lot of those steps by growing what you need, say a grid of chips of the desired dimensions directly on a carrier substrate.

As I understand it.

But we need to move to photonics.

Maybe someone can find a way to make transparent diamond.

stuff that's always transparent doesn't modulate light very well

I'd be surprise if it gets even 1% of SI world dominance after 5 years

protons wanna tunnel out.

Hadrons just wanna have fun

Okay this is cool research

just one tiny tiny microscopic question...

why would someone use diamond wafer costing 1000x more than a silicon wafer??!

> why?

>> 50x faster switching

It's hard to say which applications will benefit the most, but orders of magnitude improvement tend to enable qualitative shifts downstream.

Not to mention, 1000x is just the cost right now while the tech is new.

yeah, I get it now. I was a bit too narrow minded

If I'm reading this correctly it's two or threefold. Faster switching times, which both increases max speed and reduces power consumption. Avoids flaws due to silicon doping, presently we add ions to silicon to get P or N type junctions and they've found a way to get P type junctions using "2D Hole Gas" which is basically a thin layer of voids inside the bulk diamond crystal after treatment and avoids a category of flaws that affect silicon yields. Third, and this is speculation, but diamond has a way higher thermal conductivity and lower thermal expansion coefficient, so it can likely withstand higher temps and conduct heat away faster.

I think the better question is: what real world applications need these qualities enough to justify the cost? They mention cooling application, I don't buy that anyone is that interested in reducing hotspots in their chips even if it makes them last longer.

I had a family friend working on diamond semiconductors in the 90s. The application at that time was for sensors located in the hot section of a jet engine.

For high-voltage applications (like power supplies) or high-power high-frequency applications (like radio transmitters) or high temperature applications (e.g. inside ovens or engines) silicon transistors are already in the process of being completely replaced by silicon carbide or gallium nitride transistors.

Despite the fact that those are much more expensive than silicon transistors, they are so much better that their use saves money in other parts of the system in which they are used.

Diamond transistors could be even better than SiC and GaN transistors, but there are many difficult technological problems that must be solved until being able to make commercial products.

The linked page reports some significant advances, which avoid a source of problems in the past, which were caused by the poor behavior of dopant impurities inside diamond crystals.

> the cost?

What cost? The lab cost today, or the cost after we figure out how to make thousands a day in a diamond wafer fab?

If this were to become practical, operating high speed circuits in space might become a great deal easier due to higher temperature differential. High frequency RF in space is valuable enough that this application is certainly a candidate for such devices, even at costs far greater than Si/SiC/GaN.

Space. They are more resilient to radiation, faster, don't generate as much heat and are more tolerant of heat. That pretty much tells you where they're going to be used.

I would like to clarify your second point. The "2D Hole Gas" is not a thin layer of voids in the diamond. It is rather an absence of electrons in that layer. Holes are a pseudo particle with positive charge and a different mass from electrons (effective mass). All semiconductors have them when you excite electrons, but they're generally not used as the main charge carriers, as their mass tends to be larger than electrons, making them less mobile

gotchya

Thank you for helping me understand

The higher the voltages it can handle, the faster it can switch efficiently, and the better the thermal performance, the wider its potential applications in power electronics.

Hmm, power electronics is often so big, that might need a lot of diamond and could get pricy, who knows.

Very low power chips might be the main application, as there is already a huge market (laptops and phones).

Or maybe there will be a whole set of new rf chips, profiting from the clock speed.

Power electronics isn't just grid scale equipment.

Indeed, variable frequency drives for three-phase AC induction motors are available for single horsepower motors. A VFD rectifies the incoming AC to DC which then flows through a capacitor and into an inverter which converts the DC to quasi-sine (stepped) three-phase AC for use by the induction motor.

Possibly on a par with the other exotic materials currently in use.

The moment it becomes useful its cost will fall down to silicone prices really fast.

Right now you can buy 100g of diamonds for low teens in $ from China. Diamonds are produced in enormous quantities as abrasives. And if you do something on large scale you become better at it.

So far we haven't invested in big monocrystals because there was not much use for them aside from jewelry and probably other small niches. The moment some R&D makes something useful out of them - they will be Jevoned into oblivion.

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