Physics-Based Modeling of GaN HEMTs

A thorough approach to the investigation of GaN-based high-electron mobility transistors by device simulation is demonstrated. Due to structure and material peculiarities, new comprehensive hydrodynamic models for the electron mobility are developed and calibrated. Relying on this setup, three different independent device technologies are simulated and compared. We further study the pronounced decrease in the transconductance g_m at higher gate bias. We show that the electric field distribution and the resulting carrier velocity quasi-saturation are the main source for the transconductance collapse.