Research on Simulation Methodology for Gallium Oxide-Based MOSFETs: Electrothermal Characteristics and Reliability Degradation Mechanism

Beta-phase gallium oxide (-Ga2O), as an ultra-wide bandgap semiconductor (4.54.9 eV), demonstrates superior critical breakdown field strength (8 MV/cm) compared to SiC and GaN material systems, showing significant potential for next-generation high-power electronics. Nevertheless, inherent limitations including the absence of stable p-type doping leading to depletion-mode operation and low thermal conductivity (~27 W/mK) causing severe self-heating effects hinder practical applications. This study establishes a multi-physics coupled simulation platform using Sentaurus TCAD to systematically investigate the steady-state electrical characteristics and thermal reliability of -Ga2O MOSFETs. A self-consistent electrothermal model reveals a threshold voltage of -3.5 V and breakdown voltage of 100 V at 300 K. Thermal stability analysis demonstrates that elevated temperature (600 K) increases leakage current by two orders of magnitude due to thermally excited carrier accumulation, accompanied by a 0.8 V negative shift in threshold voltage. Defect density gradient simulations further uncover that bulk trap concentrations exceeding 110 cm-3 under off-state conditions induce significant recombination in space charge regions, triggering anomalous conduction phenomena. This work provides theoretical guidance for overcoming thermal management challenges and enhancing reliability in Ga2O3-based devices.