Enhanced Performance of Vertical β-Ga₂O₃ Schottky Barrier Diodes Through 212-MeV Low-Fluence Ge Ion Irradiation

Abstract

The effects of 212-MeV Ge ion irradiation on the electrical performance of the vertical $\beta $ -Ga2O3 Schottky barrier diode (SBD) devices have been investigated in this work. With a fluence of ${1} \times {10}^{{8}}$ ions/cm2, it is found that the electrical performance of the vertical $\beta $ -Ga2O3 SBD is significantly changed, including a decrease in the effective carrier concentration ( ${N} _{\text {D}}$ ) from $8.82\times 10^{{15}}$ to ${2.64} \times {10}^{{15}}$ cm $^{-{3}}$ , a reduction in reverse current density ( ${J} _{\text {R}}$ ) from $1.39\times 10^{-{6}}$ to $1.17\times 10^{-{7}}$ A/cm2, a restoration of the forward current density ( ${J} _{\text {F}}$ ) and series resistance ( ${R} _{\text {S}}$ ), and an increase in the reverse breakdown voltage (BV) from 218 to 420 V. Deep-level transient spectroscopy (DLTS) analysis reveals a decrease in the asymmetric defect peak at ${E} _{\text {C}}-{0.78}$ eV in the virgin sample, accompanied by the appearance of the ${E} _{\text {C}} -0.84$ eV defect peak in the irradiated sample. This indicates that Ge ion irradiation can modify the arrangement of defect levels and interface states ( ${N} _{\text {SS}}$ ), consequently leading to reshaping the distribution of asymmetric defect peaks. Additionally, technology computer-aided design (TCAD) simulations demonstrate that the weakening of the metal-semiconductor (M-S) interface state, enhanced mobility, and the presence of deep-level defects in the bulk material together contribute to alter the electrical properties of the device postirradiation. Therefore, the low-fluence Ge ion irradiation can optimize the Au/Ni/ $\beta $ -Ga2O3 interface and improve the electrical performance of the vertical $\beta $ -Ga2O3 SBD.