1.5 MeV electron irradiation damage in β-Ga2O3 vertical rectifiers

Abstract

Vertical rectifiers fabricated on epi Ga2O3 on bulk β-Ga2O3 were subject to 1.5 MeV electron irradiation at fluences from 1.79 × 1015 to 1.43 × 1016 cm−2 at a fixed beam current of 10−3 A. The electron irradiation caused a reduction in carrier concentration in the epi Ga2O3, with a carrier removal rate of 4.9 cm−1. The 2 kT region of the forward current–voltage characteristics increased due to electron-induced damage, with an increase in diode ideality factor of ∼8% at the highest fluence and a more than 2 order of magnitude increase in on-state resistance. There was a significant reduction in reverse bias current, which scaled with electron fluence. The on/off ratio at −10 V reverse bias voltage was severely degraded by electron irradiation, decreasing from ∼107 in the reference diodes to ∼2 × 104 for the 1.43 × 1016 cm−2 fluence. The reverse recovery characteristics showed little change even at the highest fluence, with values in the range of 21–25 ns for all rectifiers.