Heteroepitaxial β‐Ga ₂ O ₃ Trench‐Gate MOSFET on 4H‐SiC: Trap, Thermal, and Breakdown Optimization

A heteroepitaxial β‐Ga 2 O 3 trench‐gate MOSFET on a 4H‐SiC substrate incorporating a variable lateral doping (VLD) profile is proposed and analyzed using physics‐based technology computer‐aided design (TCAD) simulations. The trench architecture improves gate electrostatics, while the VLD drift engineering reduces electric‐field crowding and enhances breakdown robustness. The optimized device achieves a drain current of 341 mA/mm, a specific on‐resistance of 8.5 mΩ cm 2 , and an off‐state breakdown voltage of 2838 V, yielding a high‐power figure of merit of 491 MW/cm 2 . Deep‐level trap modeling is included to assess the influence of oxide and heterointerface states on device characteristics. Temperature‐dependent simulations (300–500 K) further evaluate the combined effects of traps, band‐tail states, and phonon scattering on key electrical parameters. Electro‐thermal analysis confirms that the 4H‐SiC substrate significantly mitigates self‐heating, maintaining substantially lower peak lattice temperatures than native β‐Ga 2 O 3 across a wide range of operating conditions. These results highlight the combined advantages of trench‐gate design, VLD drift optimization, and SiC‐based thermal management, establishing the proposed β‐Ga 2 O 3 /4H‐SiC MOSFET as a promising candidate for high‐voltage, high‐efficiency power switching applications.