Improved Charge Modeling of Field-Plate Enhanced AlGaN/GaN HEMT Devices Using a Physics Based Compact Model

In this paper, we present a detailed analysis on the impact of the presence of gate connected field-plate towards the source contact (GFP-S) on the high-frequency performance of GaN based high-electron mobility transistors (GaN HEMTs). We have developed an accurate physics-based model for GFP-S by enhancing the recent industry standard Advance SPICE Model for GaN HEMTs. It is found that GFP-S affects the non-linear capacitance of GaN HEMTs, thereby impacting small-and large-signal RF performance of these devices. A modification of the ASM model is described that captures these effects. The modified model is validated with measured data on a GFP-S GaN HEMT device.