Radiation effects of high-fluence reactor neutron on Ni/β-Ga₂O₃ Schottky barrier diodes

This study investigates the broad-energy-spectrum reactor-neutron irradiation effects on the electrical characteristics of Ni/β-Ga₂O₃ Schottky barrier diodes (SBDs), where the irradiated neutron fluence was up to 1 × 10¹⁶ cm⁻². On the one hand, the high neutron fluence of 10¹⁶ cm⁻² resulted in a reduction in forward current density by two orders of magnitude and an extremely high on-resistance property due to the radiation-generated considerable series resistance in the SBD. On the other hand, the irradiation brought little influence on the Ni/β-Ga₂O₃ Schottky contact, since the extracted ideality factor and barrier height from temperature-dependent current-voltage (I-V-T) characteristics showed no significant changes after the radiation. Moreover, the capacitance-voltage (C-V) characterization revealed that the net carrier density in the β-Ga₂O₃ material was only reduced by 25% at the neutron fluence of 10¹⁵ cm⁻² but a significant reduction by 2-3 orders at 10¹⁶ cm⁻². Within the neutron fluence range of 2 × 10¹⁴ cm⁻² up to 10¹⁶ cm⁻², the carrier removal rates trended to be saturated with the increased fluences, following an exponential regular. In addition, the C-V measurement on the 10¹⁶ cm⁻² irradiated sample exhibited an obvious frequency dispersion, and the extracted carrier distribution was not uniform.