The γ-Ray TID Effect and Irradiation Damage Recovery on β-Ga₂O₃/Al₂O₃ MOSCAPs

Abstract

In this study, the impact of $\gamma $ -ray total ionizing dose (TID) irradiation on the electrical performance of beta-gallium oxide ( $\beta $ -Ga2O3)/Al2O3 MOSCAPs was investigated, and a new irradiation damage recovery method was also proposed using the supercritical N2O (SCN2O) fluid postoxidation annealing (POA) process. After a cumulative $\gamma $ -ray dose of 1.108 Mrad (SiO2), the net carrier concentration ( ${N} _{\text {d}}$ ) decreased by 28.7%, and the interface state density ( ${D} _{\text {it}}$ ) increased from $4.41\times 10^{{11}}$ to $5.12\times 10^{{11}}$ ${\mathrm {eV}}^{-{1}}$ ${\mathrm {cm}}^{-{2}}$ , according to the frequency-dependent capacitance-voltage (C–V) measurements. Meanwhile, the effective trapped charge density ( ${N} _{\text {eff}}$ ) was reduced from $- 1.82\times 10^{{12}}$ to $- 1.37\times 10^{12}$ ${\mathrm {eV}}^{-{1}}$ ${\mathrm {cm}}^{-{2}}$ , leading to a decreased flat-band voltage ( ${V} _{\text {fb}}$ ), which was attributed to the formation of positively charged oxide trapped charge ( ${N} _{\text {ot}}$ ). What is more, the forward leakage current density increased by ten times, and a 9.5% decrease in the breakdown voltage ( ${V} _{\text {br}}$ ) was observed according to the current-voltage (I–V) measurements. Moreover, the leakage current analysis indicated that the changes in the I–V characteristics were primarily caused by variations in ${D} _{\text {it}}$ and ${N} _{\text {ot}}$ . In addition, after the SCN2O POA process at $120~^{\circ }$ C, the damages of the irradiated device can be repaired. Specifically, the material properties, such as ${N} _{\text {d}}$ , ${D} _{\text {it}}$ , and ${N} _{\text {eff}}$ , and the electrical properties of ${V} _{\text {br}}$ and the forward leakage current density recovered to the preirradiation level. The results demonstrated that the low-temperature SCN2O POA process is promising for repairing TID irradiation damage in $\beta $ -Ga2O3/Al2 ${\mathrm {O}}_{{3}} \cdot $ devices.