A Review of GaN Channel-Based MOSHEMTs for Next-Generation Medium/Low-Voltage Rating and High-Speed RF Power Applications

This comprehensive review delves into the intricate realm of GaN-based metal–oxide–semiconductor (MOS) high-electron-mobility transistors (HEMTs), providing an exhaustive analysis of their contemporary DC and radio-frequency (RF) performance. Despite familiar challenges in the instability of threshold voltage (V_TH) observed in GaN MOSHEMTs, recent innovations in interface technologies, incorporating in situ SiN_x and surface oxidation of (Al)GaN, have led to exceptional DC and dynamic performances, achieving stability in V_TH by reducing surface states, minimizing interface traps, controlling surface potential, and enhancing interface quality. Adoption of high-κ dielectric materials is emphasized since they are indispensable, as they play a crucial role in improving the electrostatic control of the gate and reducing parasitic capacitance, and contribute to achieving low gate leakage, high gm, small V_TH fluctuation, and small current collapse. The recent aspects of the AlGaN/GaN MOSHEMT devices are presented, and the impacts of structural breakthroughs are discussed. When compared to single-layer arrangements, the utilization of multilayer gate stacks can provide improved gate control and less leakage. Tailoring the electric field distribution and enhancing device performance for particular applications or operational conditions are made possible by engineering the gate stack arrangement. This review also discusses fabrication challenges and reliability issues in GaN-based MOSHEMTs, highlighting innovative manufacturing techniques and shedding light on ongoing research to address these challenges. By presenting a comprehensive overview of recent developments and emerging trends, this review aims to contribute valuable insights for researchers and practitioners in the dynamic and expanding field of GaN-based RF power electronics and sensing technologies.