Mechanisms responsible for dynamic ON-resistance in GaN high-voltage HEMTs

We have developed a new methodology to study the dynamic ON-resistance (R_ON) of high-voltage GaN High-Electron-Mobility Transistors (HEMTs). With this technique, we have investigated dynamic R_ON transients over a time span of 11 decades. In OFF to ON time transients, we observe a fast release of trapped electrons through a temperature-independent tunneling process. We attribute this to border traps at the AlGaN barrier/AlN spacer interface. Over a longer time scale, we observe conventional thermally activated electron detrapping from traps at the surface of the device or inside the AlGaN barrier. These findings provide a path for power switching device engineering with minimum dynamic R_ON.