Drain current DLTS of AlGaN/GaN HEMTs

The transient behaviour of AlGaN/GaN HEMTs was studied by current DLTS. One electron trap and two hole-trap-like signals were observed. The electron trap had an activation energy of 0.61 eV, which was similar to the defect level in n-GaN obtained by capacitance DLTS. It has been pointed out that the hole-trap-like signals dit not originate from changes in hole trap population in the channel, but probably reflected the changes in the electron population in the surface states of the HEMT access regions.