Field-Plated Lateral Ga2O3 MOSFETs With Polymer Passivation and 8.03 kV Breakdown Voltage

This letter reports the polymer passivation of field plated lateral beta-Ga2O3 MOSFETs with significant improvement in the breakdown voltages as compared to non-passivated devices. We show consistent results of higher breakdown voltages in passivated devices as compared to non-passivated devices for MOSFETs with L-gd ranging from 30 mu m to 70 mu m and across two process runs. We obtain a record high breakdown voltage of 6.72 kV for a MOSFET with L-gd = 40 mu m giving an average field strength of 1.69 MVcm(-1). The peak drain current is similar to 3 mA/mm for Lg = 2 mu m device with a gate source separation of 3 mu m. The on-resistance for the device is, R-on = 13 k Omega.mm, giving a power device Figure of Merit of 7.73 kWcm(-2). The R-on is high due to plasma induced damage of channel and access regions. The R-on and on-current density remain unchanged after passivation. The breakdown increases with L-gd up to 70 mu m, giving a maximum breakdown voltage of 8.03 kV.