Single-Event Burnout by Cf-252 Irradiation in Vertical $\beta$-Ga2O3 Diodes with Pt and PtOx Schottky Contacts and High Permittivity Dielectric Field Plate

$\beta$-Ga2O3 is an ultrawide-bandgap material (4.6–4.9 eV) with a theoretical breakdown field of about 8 MV/cm [1]. Very few experimental results have been reported so far on the radiation response of $\beta$-Ga2O3. In this work, ion-induced single-event burnout (SEB) is experimentally observed in two structurally different types of $\beta$-Ga2O3 Schottky diodes. SEB occurred by Cf-252 irradiation with voltages well below the electrical breakdown for both device structures. However, devices having PtOx Schottky barrier contacts (SBCs) with TiO2 field plates (FPs) showed higher SEB thresholds compared to devices having Pt SBCs with ZrO2 FPs. While the Pt SBC with ZrO2 FP $\beta$-Ga2O3 devices with $\sim 8.5\ \mu \mathrm{m}$ drift layer failed at −310 V reverse bias with Cf-252 irradiation, devices having PtOx SBCs with TiO2 FPs functioned properly up to −400 V despite having significantly less drift layer thickness of $\sim 4\ \mu \mathrm{m}$. The increased Schottky barrier height (SBH) with the PtOx SBC and/or the extreme-k permittivity dielectric TiO2 FP resulted in a higher electrical breakdown voltage and a better radiation response for the $\beta$-Ga2O3 diodes.

Introduction

-Ga₂O₃ is an ultrawide-bandgap material (4.6–4.9 eV) with a theoretical breakdown field of about 8 MV/cm [1]. Very few experimental results have been reported so far on the radiation response of -Ga₂O₃. In this work, ion-induced single-event burnout (SEB) is experimentally observed in two structurally different types of -Ga₂O₃ Schottky diodes. SEB occurred by Cf-252 irradiation with voltages well below the electrical breakdown for both device structures. However, devices having PtO_x Schottky barrier contacts (SBCs) with TiO₂ field plates (FPs) showed higher SEB thresholds compared to devices having Pt SBCs with ZrO₂ FPs. While the Pt SBC with ZrO₂ FP -Ga₂O₃ devices with drift layer failed at −310 V reverse bias with Cf-252 irradiation, devices having PtO_x SBCs with TiO₂ FPs functioned properly up to −400 V despite having significantly less drift layer thickness of . The increased Schottky barrier height (SBH) with the PtO_x SBC and/or the extreme-k permittivity dielectric TiO₂ FP resulted in a higher electrical breakdown voltage and a better radiation response for the -Ga₂O₃ diodes.