Effect of 20 MeV proton irradiation on the electrical properties of β-Ga₂O₃ Schottky barrier diodes with field plate

In this Letter, the impact of 20 MeV proton irradiation on β-Ga₂O₃ Schottky barrier diodes (SBDs) with field plates has been investigated. After proton irradiation with fluences of 2 × 10¹² and 5 × 10¹² p/cm², the forward current density (J_F) decreased from 294.0 to 250.5 and 192.0 A/cm², respectively. The turn-on voltage (V_on) increased from 0.78 to 0.82 and 0.84 V, as measured by current-voltage (I-V) testing. Capacitance-voltage (C-V) measurements showed that the net carrier concentration in the lightly doped drift region of β-Ga₂O₃ decreased from 1.95 × 10¹⁶ to 1.83 × 10¹⁶ and 1.38 × 10¹⁶ cm⁻³ after proton irradiation. Additionally, C-V measurements at different frequencies reveal that capacitance gradually decreases as proton fluence increases, though the frequency has little effect on capacitance. The effect of proton irradiation on β-Ga₂O₃ SBDs was also characterized using low-frequency noise and x-ray photoelectron spectroscopy. The results indicated that the voltage noise spectral density (S_v) gradually increases with proton fluence and bias voltage before and after irradiation due to the introduction of defects. This study provides an important reference for the reliability assessment of β-Ga₂O₃ SBDs.