Charge Trapping in Al2O3/ \beta -Ga2O3-Based MOS Capacitors

Trapping characteristics of MOS structures with β-Ga 2 O 3 substrates and Al 2 O 3 gate dielectrics are evaluated via constant-voltage stress and X-ray irradiation. Traps that affect bias-induced charging are located primarily in the Al 2 O 3 dielectric layer, and are distributed broadly in time and/or energy. Stress-induced flatband voltage shifts are reduced by N 2 annealing. Trap-assisted tunneling is shown to be responsible for the observed gate leakage. Hole trapping in the Al 2 O 3 dielectric layer dominates device radiation response. The relatively modest radiation-induced charge trapping observed in these devices is promising for the potential future use of Al 2 O 3 /β-Ga 2 O 3 devices in a space environment.