What happened to Gallium-Arsenide? Wasn't that going to replace silicon? Did it not pan out? Is it used in some cases?
I really know nothing about the state of semiconductor materials, obviously!
I really know nothing about the state of semiconductor materials, obviously!
Not exactly sure why the tech is not more widely used though. Funnily enough, most of the GaN and GaAs devices in general use are LEDs!
This article's transistors will not likely have a high switching speed, just high enough for switching power converters (100kHZ-few MHZ). The important feature of GaN according to the article is that you generate 1/10 the waste heat from current just flowing through the switch.
Power transistors don't perfectly 'turn on' like an ideal switch. They have a resistance to the switched path on the order of milliohms called Rds (resistance source to drain). And, heat dissipated from that is ~ I^2 x Rds.
My guess is that this is a breakthrough because it has lower resistance per unit of gate capacitance. It takes a certain amount of energy to switch the transistor on, and when you want to turn it off you generally connect it to ground so that the switch turns off very quickly. That energy is lost.
I've emailed a very experienced electronics engineer friend of mine who has built more switching power supplies than anyone I know. He hasn't gotten back to me yet.
It really has to be something more than the "on" resistance though. It's possible to get arbitrarily large MOSFETs and get micro-ohm resistance, where as the GaN transistor has milli-ohm resistance.
http://www.digikey.com/product-detail/en/TPHR9003NL,L1Q/TPHR...