GaN HEMT modeling for power and RF applications using ASM-HEMT

In this paper, we aim to present an overview of a surface-potential (SP) based model named “Advanced Spice Model for High Electron Mobility Transistor” (ASM-HEMT) for AlGaN/GaN HEMTs. This model is presently under consideration in the phase-III of industry standardization by the Compact Model Coalition (CMC). SP of GaN HEMT is obtained by solving Schrodinger and Poisson equations in the triangular potential well considering the first two energy subbands. The core drain current model and a intrinsic charge model are derived using the developed SP model. Various real device effects like: velocity saturation, drain-induced barrier lowering (DIBL), self-heating, field dependent mobility, non-linear access region resistances etc. are included in the core drain current model to represent real GaN HEMTs. Field-plate (FP) model is incorporated to predict accurate current and capacitance trends observed in the high power GaN HEMTs with source and gate connected field-plates. Along with the gate current model, non-linear trapping effects are also included in the model to capture larghe-signal high-frequency device behavior. This model is extensively validated with the experimental data of both high power and high frequency GaN HEMTs.