Investigation of the dynamic on-state resistance of 600V normally-off and normally-on GaN HEMTs

摘要

In this paper, current collapse phenomena and thermal effects in newly developed normally-off and normally-on GaN HEMTs are investigated. The experimental results show that a high off-state voltage and high switched drain current at high junction temperature cause an increase of the on-state resistance. During switching from 50 kHz to 400 kHz, an increase of RDSON is observed for both types of GaN devices. It is evident that the number of switching transients significantly influences the increase of the on-state resistance, suggesting that this increase is due to a current collapse in GaN HEMTs. A detailed comparison of the evaluated RDSON between GaN transistors and the newest high-speed CoolMOS-C7 transistor is presented.