Investigation on the high temperature behaviour of p-GaN HEMTs by different temperature sensitive electrical parameters

Due to recent improvements and technical advantages in applications with high switching frequencies, research is increasingly focusing on GaN high electron mobility transistors (HEMTs). An accurate temperature determination is thereby of particular importance to give precise lifetime estimations and define safe operation areas. This work investigates on the temperature estimation by means of the temperature sensitive electrical parameters (TSEPs) R_DS,on (T) and V_GS (T) of GIT-type transistors, supported by an IR-camera. Several Z_th characteristics were measured, whereby the temperature estimation with V_GS (T) appears to be superior. Furthermore, the investigation includes static and dynamic characterization as well as power cycling tests (PCT) with switching losses at high temperature above the datasheet limit of 150°C. The device operates stable and reliable at a junction temperature of 175°C in the PCT.