Performance and Reliability Enhancement of GaN/BGaN HEMTs using Cu/Fe Trap Engineering for Improved 2DEG and RF Characteristics

Abstract

This work presents a comprehensive investigation of performance and reliability enhancement in GaN/BGaN high electron mobility transistors (HEMTs) through dual trap engineering using copper (Cu) and iron (Fe) layers on a SiC substrate. The proposed device incorporates a GaN cap, n-type BGaN barrier, BGaN spacer, and GaN channel to facilitate strong polarization-induced 2DEG formation at the heterointerface. The introduction of Cu and Fe trap layers within the buffer region is systematically analyzed using TCAD simulations to evaluate their impact on electrical, RF, and reliability characteristics. The results demonstrate a significant improvement in device performance with trap engineering. The drain current (I_DS) increases from 700 mA/mm in the conventional structure to 756 mA/mm and 784 mA/mm for Fe and Cu trap configurations, respectively. Similarly, the transconductance (g_m) improves from 130 mS/mm to 140 mS/mm and 145 mS/mm. RF performance analysis reveals variations in gate-source and gate-drain capacitances, indicating enhanced charge control and reduced parasitic effects. Notably, the minimum noise figure is reduced from 10.7 dB to 10.2 dB in the Cu trap-based device, highlighting its suitability for low-noise applications. From a reliability perspective, the peak electric field is significantly reduced in the Fe trap structure (77,514 V/cm) and remains controlled in the Cu trap case (88,480 V/cm), compared to 122,304 V/cm in the conventional device. This reduction mitigates hot carrier effects and enhances device stability. The improved performance is attributed to enhanced carrier confinement, optimized 2DEG density, and effective suppression of leakage through trap-assisted field redistribution. Overall, the proposed Cu–Fe trap-engineered GaN/BGaN HEMT demonstrates superior electrical, RF, and reliability characteristics, making it a promising candidate for next-generation high-frequency and high-power electronic applications.