High-Performance BGaN/GaN HEMT Design with Si3N4 Passivation for RF and Microwave Applications

This work presents the model and simulations of a BGaN/GaN-based high electron mobility transistor (HEMT) with a gate length of 3 μm, using Sentaurus TCAD. To improve surface passivation and device stability, Si3N4 is employed as the passivation layer. The simulated device demonstrates a significantly IDmax of 1128 mA/mm at a VG of 2.5 V, indicating excellent current-driving capability. A peak gm of 142 mS/mm is achieved at VGS = 2 V. In comparison, the maximum gds reaches 184 mS/mm at VDS = 45 V. These improvements reflect enhanced channel control and carrier transport efficiency. The Cgs and Cgd capacitances were extracted to assess the device’s RF performance. A minimum noise figure of 10.7 dB is observed at an operating frequency of 5 GHz, confirming its suitability for low-noise, high-frequency applications. Compared to conventional AlGaN/GaN HEMTs, the proposed BGaN/GaN HEMT exhibits superior electrical and noise characteristics. These results establish BGaN as a promising barrier material for next-generation high-power and microwave transistor applications, offering enhanced current density, gain, and noise performance. The simulated performance parameters suggest that this structure is highly suitable for integration into RF power amplifiers, radar, and wireless communication systems.