Multibias TCAD Analysis of Trap Dynamics in GaN HEMTs

In this paper we exploit numerically efficient physical simulations to investigate the link between GaN HEMT low-frequency dispersion and the concentration of Fe induced buffer traps. We demonstrate that the sensitivity of the AC output conductance to trap concentration shows markedly different behavior according to the bias point, either in saturation or in the linear region at the HEMT knee voltage. The frequency dependency and the sensitivity of AC parameters in multiple bias points yield a deeper understanding of trap behavior and allow for easier identification of buffer trap signature in characterization data.