Impact of buffer composition on the dynamic on-state resistance of high-voltage AlGaN/GaN HFETs

Abstract

Switching experiments with normally-off GaN-HFETs using a carbon-doped GaN buffer or an AlGaN buffer showed very different magnitudes of increased dynamic on-state resistance. The dynamic on-state resistance is analyzed for variations in buffer composition and set into relation to the buffer voltage-blocking strength. Also, the impact of p-GaN gate normally-off and Schottky-gate normally-on device technologies on the dispersion is studied. It is concluded that a buffer with less trap sites and lower breakdown strength is more favorable for high-voltage switching than a buffer with incorporated acceptors to increase the buffer breakdown strength.