(Invited) Modeling reliability in GaN HEMTs

In this paper we present modeling reliability concerns in GaN HEMT technology. A theoretical model was developed to model the piezoelectric polarization charge dependence on the applied gate voltage. To model self-heating effects, an elec-tro-thermal device simulator was developed that couples the Monte Carlo-Poisson solver with the energy balance solver for the acoustic and optical phonons. Current collapse was explained as charging the surface states due the Paul-Frenkel tunneling from the gate into the gate to drain extension. Excellent agreement is obtained between the theoretical calculations and the experimental data of the unstressed and the stressed devices with this model.