Performance Improvement of Enhanced-Mode β-Ga₂O₃ MOSFETs by Partial Gate Recess Structure

In this study, β-Ga2O3 films were grown on the c-plane sapphire substrate by metal–organic chemical vapor deposition. Gate-recessed heteroepitaxial β-Ga2O3 metal oxide semiconductor field effect transistors (MOSFETs) were fabricated to achieve enhanced mode operation. It was found that the conductivity of Ga2O3 films can be further improved by in situ doping and a partial gate recess. Output current increased from 4.21 to 5.76 mA/mm, Ron.sp decreased from 392 mΩ.cm2 to 238 mΩ.cm2,and μFE increased from 15 cm2/(V s) to 19.9 cm2/(V s) for MOSFETs with partial gate recesses of 7 and 5 μm, respectively. Device threshold voltages are positive, possessing low Ron and impressive ID on/off ratios. Breakdown voltage was increased using a gate field plate. In summary, device performance was improved using shorter gate recesses for enhanced mode β-Ga2O3 MOSFETs.