Impact of high-power stress on dynamic ON-resistance of high-voltage GaN HEMTs

We have investigated the impact of high-power (HP) stress on the dynamic ON-resistance (R-ON) in high-voltage GaN High-Electron-Mobility Transistors (HEMTs). We use a newly proposed dynamic R-ON measurement methodology which allows us to observe R-ON transients after an OFF-to-ON switching event from 200 ns up to any arbitrary length of time over many decades. We find that HP-stress results in much worsened dynamic R-ON especially in the sub-ms range with minor changes on a longer time scale. We attribute this to stress-induced generation of traps with relatively short time constants. These findings suggest that accumulated device operation that reaches out to the HP state under RF power or hard-switching conditions can result in undesirable degradation of dynamic R-ON on a short time scale. (C) 2012 Elsevier Ltd. All rights reserved.