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

Abstract

This letter reports the polymer passivation of field plated lateral $\beta $ -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 $\text{L}_{\textit {gd}}$ ranging from $30~\mu \text{m}$ to $70~\mu \text{m}$ and across two process runs. We obtain a record high breakdown voltage of 6.72 kV for a MOSFET with $\text{L}_{\textit {gd}}= {40}\mu \text{m}$ giving an average field strength of 1.69 MVcm−1. The peak drain current is $\sim ~3$ mA/mm for $\text{L}_{g}= {2}\mu \text{m}$ device with a gate source separation of $3~\mu \text{m}$ . The on-resistance for the device is, $\text{R}_{\textit {on}}= {13}\,\,\text{k}\Omega ^{.}$ mm, giving a power device Figure of Merit of 7.73 kWcm−2. The $\text{R}_{\textit {on}}$ is high due to plasma induced damage of channel and access regions. The $\text{R}_{\textit {on}}$ and on-current density remain unchanged after passivation. The breakdown increases with $\text{L}_{\textit {gd}}$ up to 70 $\mu \text{m}$ , giving a maximum breakdown voltage of 8.03 kV.