1.5 MeV electron irradiation damage in β-Ga₂O₃ vertical rectifiers

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 × 10¹⁶cm⁻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.