Impact of electrical degradation on trapping characteristics of GaN high electron mobility transistors

One of the most deleterious effects of electrical degradation of GaN HEMTs is an increase in carrier trapping and subsequent current collapse. In this work, we have investigated the trapping and detrapping characteristics of GaN HEMTs before and after device degradation through a new current transient analysis methodology. We have found that electrical stress beyond a critical voltage significantly enhances trapping behavior inside the AlGaN barrier layer or at the surface. However, trapping in the buffer was found to be intact after device degradation.