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Comment by nayuki | Hacker News Reader

How does silicon carbide compare to gallium nitride, another semiconductor that features high frequencies and low losses?

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GaN has higher electron mobility but SiC has higher thermal conductivity.

So GaN is more efficient for higher frequencies and higher power and SiC is better for high temperatures and has higher potential power density than GaN

SiC will be cheaper and probably dominate GaN in production volume. Epitaxial GaN on SiC (and even GaN on diamond substrate) are used for high power, low noise at high frequency RF where the applications can justify the cost.

There are RF power devices that consist of GaN structures built on a CVD diamond substrate.

Diamond's thermal conductivity is uniquely high. The diamond substrate conducts heat away from the GaN FETs.

RFHIC uses this technology in some of its high power microwave sources and amplifiers.

GaN is way worse for higher power levels, thus absence of it in high power power electronics.

I haven't seen GaN transistor lower than 100mOhms, SiC is easily there.

I am talking about relatively high voltage ones

I can't think of a manufacturer off-hand where even a majority of their 600V+ GaN power devices have a static on-resistance of at least 100 mΩ. Infineon, GaN Systems, Transphorm, Nexperia, and TI are all majority less.

Are you in power electronics?

Physically, no. I wouldn't fit.

Then, mentally?

Yes

In what kind of power electronics? Chargers, inverters, matrix converters, VFDs?

Order of magnitude cheaper, not as efficient for photonics, can be integrated with Si through epitaxy.

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