Surface-Potential-Based RF Large Signal Model for Gallium Nitride HEMTs

We present a physics based large signal RF compact model for Gallium Nitride HEMTs (GaN HEMTs). This surface-potential-based model is called Advance SPICE Model for GaN HEMT or ASM-GaN-HEMT model. Surface-potential (SP) in the triangular quantum well of GaN HEMTs is derived by solving Schrodinger´s and Poisson´s equations consistently and analytically. Core analytical drain-current model is derived using the developed SP model and drift-diffusion transport. The core model is enhanced with models for key real device effects to represent a real GaN HEMT device. A consistent intrinsic charge model is also derived from SP. The developed model is implemented in Verilog-A. Excellent model agreement with DC, S-parameters and large signal RF power sweep measurements are shown for a GaN HEMT device with width W = 40 μ956;m and number of fingers NF = 8.