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

$\beta$
-Ga
2
O
3
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
$\beta$
-Ga
2
O
3
. In this work, ion-induced single-event burnout (SEB) is experimentally observed in two structurally different types of
$\beta$
-Ga
2
O
3
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 TiO
2
field plates (FPs) showed higher SEB thresholds compared to devices having Pt SBCs with ZrO
2
FPs. While the Pt SBC with ZrO
2
FP
$\beta$
-Ga
2
O
3
devices with
$\sim 8.5\ \mu \mathrm{m}$
drift layer failed at −310 V reverse bias with Cf-252 irradiation, devices having PtO
x
SBCs with TiO
2
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 PtO
x
SBC and/or the extreme-k permittivity dielectric TiO
2
FP resulted in a higher electrical breakdown voltage and a better radiation response for the
$\beta$
-Ga
2
O
3
diodes.