Impact of the buffer structure on trapping characteristics of normally-off p-GaN/AlGaN/GaN HEMTs for power switching applications

Drain current trapping characteristics were systematically analyzed and compared on normally-off p-GaN/AlGaN/GaN HEMTs for power switching applications, grown on AlGaN/GaN double and Fe-doped GaN single heterostructures with and without Ar implantation into n-SiC substrate. Spatial location of traps was studied using comparison between trapping behaviour of devices with and without field-plate electrode and correlation between early-stage degradation modes and trapping behaviour. Our results indicate that for HEMTs grown on DH buffer, trapping process with time constant in the seconds range may be mitigated by Ar implantation into SiC.