Watch Out SiC, Diamond Power Semiconductors Are Coming For You!

The vast majority of semiconductors products we use every day are primarily constructed on a silicon process, using wafers of pure silicon. But whilst the economics are known, and processes mature, there are still some weaknesses. Especially for power applications. gallium nitride (GaN) and silicon carbide (SiC) are materials that have seen an explosion in uses in the power space, driven especially by an increase in electric vehicle sales and other high-power/high-voltage systems such as solar arrays. But, SiC is expensive and very energy intensive. It looks like diamond substrates could become much more common if the work by Diamfab takes off.

Diamond, specifically thin films of synthetic diamond formed on a suitable substrate, exhibits many desirable properties, such as a vastly superior maximum electric field compared with silicon, and a thermal conductivity five times better than copper. Such properties give diamond structures a big power and voltage advantage over SiC, which is in turn a lot better the pure silicon. This also means that diamond-based transistors are more energy efficient, making them smaller and cheaper, as well as better performing. Without the high formation temperatures needed for SiC, diamond could well be their downfall, especially once you factor in the reduced environmental impact. There is even some talk about solid-state, high-voltage diamond insulator capacitors becoming possible. It certainly is an interesting time to be alive!

We do cover news about future semiconductors from time to time, like this piece about cubic boron arsenide. We’ve also seen diamond being used as a battery, albeit a very weak radiative one.

[via EETimes]

22 thoughts on “Watch Out SiC, Diamond Power Semiconductors Are Coming For You!

  1. You might want to correct the title. It took me a few beats to realize that the substance in question is “SiC”, (silicon carbide), and not “SIC”.

        1. I have a CSS override to read Hackaday in a nice black-on-light-grey theme that doesn’t kill my eyes. It also changes the titles to “text-transform: none; font-variant: small-caps;”, which maintains the ALL CAPS look while still allowing you to see mixed-case text.

  2. Did some undergraduate research into fast switching diamond diodes (kV/ps scale switching!). They are the widest bandgap conductor and would be great for things like ultra wideband radar.

    Wrote a paper based on the semiconductor simulations but none of the IEEE transactions editors would accept it…. So on arXiv it shall remain….

    Few main issues are purity of the grown diamond substrate and the fact that there is almost no ionization at room temp. With enough persistence and some clever doping methods we could see some real applications in the future!

  3. “Without the high formation temperatures needed for SiC, diamond could well be their downfall” What does this mean? I thought diamond manufacture involved high pressure and temperature?

    1. I remember an article many years ago (but not the source unfortunately) about researchers forming diamond thin films in a microwave oven with a mostly methane or natural gas atmosphere. Possibly on There are often ways to “cheat” in physics it seems.

      1. I won’t bother with a link since it takes 8 hours for replies with links to show up here, but look up “diamond synthesis using an oxyacetylene torch” by Hanssen et al. Back in the 80’s they were producing very thin film diamond coatings at ambient air pressure with a blowtorch against a copper substrate. More recent development of this same process with more specialized equipment has gotten thicker and higher quality diamond films.

  4. When it comes to military and aerospace applications, cost isn’t a huge factor. If they are better for the job then they will get used. Making it commonplace is the real test.

    1. As someone from Mil-Aero, I doubt the usgov would approve their use in anything production until like 20 years after they’ve been in industry. Sure they’ll be IRADs demonstrating the effectiveness but at this point Industry’s probably close to if not already leading in fielding a lot of the cutting edge stuff. Mil-Aero just has the advantage of not having to completely cut costs to paper thin margins and can field more expensive stuff. Having to design stuff to fit in a 20 year old power architecture meant to run PowerPCs cause it’s “Tried and True” is a huge PITA. Literally in the past 5 years, I’ve been on programs that had to fight tooth and nail just to allow parts with copper wire bonds and we ended up getting exceptions simply because most of the available parts don’t even use gold anymore. If more people would understand it, I would replace some of my 4 letter words with PMAP.

  5. Diamond is about 5.5x as good as copper in theory. And silver is only a little better than copper, for reference. And it is even better if you happen to use higher purity carbon-12 to make the diamond, or if you operate at cryo temperatures IIRC. Neat stuff.

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