Influence of Accurate Electron Drift Velocity Modelling on the Electrical Characteristics in GaN-on-Si HEMTs

The influence of an accurate electron velocity-field relationship modelling on pulsed IV and small-signal RF characteristics in GaN-on-Si HEMTs is discussed and compared to measurements. We show by technology computer-aided design (TCAD) simulation and measurements that not only the lowfield mobility and saturation velocity are of great importance, but also the transition behaviour in between has to be modelled accurately. Experimentally, we extract the velocity-field relationship using device simulation and measured data with ultra short pulse lengths. To the best of our knowledge, this is the first study on the velocity-field relationship in GaN-on-Si devices.