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

This letter reports the polymer passivation of field plated lateral β -Ga₂ O₃ 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 30μm to 70μm and across two process runs. We obtain a record high breakdown voltage of 6.72 kV for a MOSFET with L_gd= 40μm giving an average field strength of 1.69 MVcm^-1. The peak drain current is ∼ 3 mA/mm for L_g= 2μm device with a gate source separation of 3μm. The on-resistance for the device is, R_on= 13kΩ. 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 μm , giving a maximum breakdown voltage of 8.03 kV.