3 ms·

SiC and GaN are being used for a fair number of parts these days for RF applications. It seems that the novel part of this paper is that the device worked up to

SiC and GaN are being used for a fair number of parts these days for RF applications. It seems that the novel part of this paper is that the device worked up to 500C. The device worked for 3 hours with some degradation, likely due to Al electromigration from the metallization. The acutal paper is here: https://ieeexplore.ieee.org/document/8345290/ https://ieeexplore.ieee.org/document/8345290/

namibj 8y ago
I thought >300C power MOSFETs in SiC were already commercially available? But I might be confused.
darkmighty 8y ago
I wonder if simply cooling isn't an option in those applications? I guess that'd depend on the chips power output. Otherwise you could just surround it in a really good insulator and pump residual heat out somehow (maybe can peltiers withstand such high temps using multiple stages?)
- BostonEnginerd 8y ago
  Cooling only works if you have somewhere to put the extra energy. Peltiers are inefficient to run and generate a ton extra heat. It's best to build something that can run with as little support needed.
  - darkmighty 8y ago
    Indeed, cooling would be quite bulky and require lots of extra energy. But for an environment like Venus cited (instead of small sensors), I think it should be a good option. The Carnot efficiency to cool from a Venutian environment (462C) down to 50C (reasonable chip temp) is a surprisingly good ~60%. In practice you might get 15% (? plus insulation leaking), that should still allow cooling a chip of less than ~1 watt of tdp without too much hassle inside a robot.
madengr 8y ago
I was going to say my employer made this stuff, but they are getting out of the business. Must not be profitable enough. https://aerospace.honeywell.com/en/products/navigation-and-sensors/high-temperature-microelectronics https://aerospace.honeywell.com/en/products/navigation-and-s... SOI is an excellent RF process, and is what would be needed to get the rest of the radio on there.

namibj 8y ago

I thought >300C power MOSFETs in SiC were already commercially available? But I might be confused.

darkmighty 8y ago

I wonder if simply cooling isn't an option in those applications? I guess that'd depend on the chips power output. Otherwise you could just surround it in a really good insulator and pump residual heat out somehow (maybe can peltiers withstand such high temps using multiple stages?)

BostonEnginerd 8y ago
Cooling only works if you have somewhere to put the extra energy. Peltiers are inefficient to run and generate a ton extra heat. It's best to build something that can run with as little support needed.
- darkmighty 8y ago
  Indeed, cooling would be quite bulky and require lots of extra energy. But for an environment like Venus cited (instead of small sensors), I think it should be a good option. The Carnot efficiency to cool from a Venutian environment (462C) down to 50C (reasonable chip temp) is a surprisingly good ~60%. In practice you might get 15% (? plus insulation leaking), that should still allow cooling a chip of less than ~1 watt of tdp without too much hassle inside a robot.

madengr 8y ago

I was going to say my employer made this stuff, but they are getting out of the business. Must not be profitable enough. https://aerospace.honeywell.com/en/products/navigation-and-sensors/high-temperature-microelectronics https://aerospace.honeywell.com/en/products/navigation-and-s... SOI is an excellent RF process, and is what would be needed to get the rest of the radio on there.