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

Trapping characteristics of MOS structures with
$\beta $
-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
/
$\beta $
-Ga
₂
O
₃
devices in a space environment.