β-Ga2O3Dielectric Superjunction Schottky Barrier Diode Exceeding SiC Unipolar Figure of Merit: A Novel Approach to Realizing Superjunction Devices Without p-type Doping

Abstract

We demonstrate lateral β-Ga2O3 Schottky barrier diode (SBD) with a high permittivity (high-k) dielectric superjunction (SJ) structure. Extreme permittivity dielectric (BaTiO3) with dielectric constant of 220 is used to uniformly distribute the electric field in a MOVPE-grown lateral drift layer, which circumvents the extreme difficulties in achieving charge balance using conventional p-n superjunction structures in β-Ga2O3 due to the lack of shallow acceptors. SBD on an epilayer with a sheet charge of 1.5×10¹³ cm²demonstrates a specific on resistance (Ron-sp) of 0.83 mΩ-cm^-2and a breakdown voltage VBR of 1487 V for an anode to cathode length of 5 microns, rendering a Power figure of Merit (PFOM) of 2.7 GW/cm-² when normalized to the active current conducting area. These results using the proposed device structure demonstrates the promise of β-Ga2O3-based devices in multi-kilovolt class applications.