Current collapse phenomenon that occurs in GaN HEMTs under a moderately large DC bias stress, poses serious problems for usage of GaN technology in high-power high-frequency applications from a reliability standpoint. Additional problem in these devices operated at high biases is the appearance of self-heating effects that degrade device characteristics and, as shown in this work further amplify the problem of current collapse by changing the device electrostatics.
Current slump mechanism and its physical model of AlGaN/GaN HEMTs under DC bias