Electric field dependent drain current drift of AlGaN/GaN HEMT

Abstract

We have performed constant voltage stress (CVS) tests on GaN-on-SiC HEMT to investigate the drain current drift. Two kinds of current drift behavior are observed in CVS. The off-state drain voltage step stress tests are carried out to confirm the electric field dependent current drift. A critical voltage for drain current recovery is observed. We suggest that the recovery of drain current is due to holes generation near the heterojunction interface or the detrapping of acceptors in the barrier layer. The drain current drift is balanced by the current degradation and recovery mechanism.