Investigation of the Degradation Mechanism of β-Ga2O3 SBD on 5 MeV Proton Irradiation

The effects of 5 MeV proton irradiation on the electrical performance of β-Ga2O3Schottky barrier diodes (SBDs) are studied in this article to demonstrate the degradation mechanism and behavior related to defects and energy band. After proton irradiation with a fluence of 1 × 1013n/cm2, the forward current density of β-Ga2O3SBD decreases, the barrier height rises by 0.2 eV, and the ideality factor degenerates from 1.056 to 1.092. The carrier concentration in the epilayer (from 1.05 × 1016to 0.3 × 1016cm-3), obtained fromC–Vcharacteristics, notably reduces due to trap states in the drift layer, leading to a higher barrier height. On the other hand, the Poole–Frenkel emission (PFE) mechanism is found to cause the reverse leakage of β-Ga2O3SBD after proton irradiation, utilizing temperature-dependent current-voltageI–Vmeasurements. The deep-level transient spectroscopy (DLTS) measurements further reveal thatEc-0.82 eV (shifted toEc-0.81 eV) originates from preexisting defects, whileEc-0.72 eV andEc-1.04 eV are newly introduced by the proton irradiation. The relatively shallow trap statesEc-0.72 eV with a large capture cross section (2.25 × 10-12cm-2) contribute to PFE and dominate the trap-assisted leakage. Finally, the lower trap activation energy (from 0.82 to 0.72 eV) and higher Schottky barrier height (from 0.90 to 1.18 eV) both result in the degradation of both forward conduction and reverse leakage in β-Ga2O3SBDs.