TCAD analysis of GaN HEMT AC parameters through accurate solution of trap rate equations

Physics-based simulations allow for an accurate insight into the impact of trap dynamics on GaN HEMT performance. In particular, traps are responsible for the low-frequency dispersion of AC performance, e.g. the Y parameters. In this paper we present an in-house TCAD simulator implementing the trap rate equations coupled to the drift-diffusion physical model and solved through the Harmonic Balance algorithm. The developed TCAD allows for the extraction of the trap rate equations Green’s Functions (GFs) in the frequency domain. GFs are then used to compute the sensitivity of the AC Y parameters towards variations of the trap physical parameters (e.g. the trap energy) and to extract the local sensitivity, showing the parts of the device where traps influence most the HEMT AC parameters.