Demonstration of <b> <i>β</i> </b>-Ga2O3 vertical Schottky barrier diode with mesa termination assisted partially suspended field plate on MOCVD-grown epitaxial wafer

Abstract

This Letter demonstrates a beta-phase gallium oxide (β-Ga2O3) vertical Schottky barrier diode (SBD) with mesa termination assisted by a partially suspended field plate, which is fabricated on the epitaxial thick film grown by metal–organic chemical vapor deposition. The epitaxial film features a high-quality, smooth surface and high mobility, laying the foundation for achieving high performances. In the device aspect, the mesa termination and the partially suspended field plate, which can be formed simultaneously by adding Cl2 during the inductively coupled plasma etching process to facilitate isotropic etching of β-Ga2O3, effectively mitigate the electric field crowding phenomenon at the device edge, thereby reducing the electric field peaks both in the epitaxial layer and dielectric layer and improving the breakdown voltage (BV). The experimental results show that the proposed SBD achieves a high BV of 3.45 kV and a low specific on resistance of 3.88 mΩ cm2, yielding a high power figure of merit of 3.07 GW/cm2. Meanwhile, a low forward voltage (at 100 A/cm2) of 1.25 V can also be obtained, verifying the low conduction loss property.