ASM-HEMT: industry standard GaN HEMT model for power and RF applications (invited paper)

An overview of a surface-potential (SP) based model for AlGaN/GaN HEMTs named "Advanced SPICE Model for High Electron Mobility Transistor" (ASM-HEMT) is presented in this paper. Recently, our model has been selected as industry standard model for GaN HEMTs by Si2-Compact Model Coalition (CMC) after more than five years of rigorous evaluation and testing by semiconductor companies. In our model, we preserve the 2DEG nature of the channel by self-consistently solving the Schrödinger's and Poisson's equations to obtain an analytical expression for the surface-potential after considering two energy sub-bands in the triangular quantum well at the hetero-interface. We proceed to calculate all other important quantities such as the intrinsic charges, drain current etc. in terms of the surface potential, valid for a wide range of bias conditions. We have incorporated real device effects such as Access Resistances, Drain Induced Barrier Lowering (DIBL), Mobility Degradation, Channel Length Modulation, Self-Heating, Gate Current, Noise, Field-Plates etc. We have a working trap model incorporated into the main model and it is validated against pulsed IV measurements, harmonic balance power sweeps and load pull for a commercial RF GaN HEMT. We have also validated the model for power devices with field plates and have been able to accurately capture the capacitances incorporated due to the field plates.