Fundamental Understanding of Oxide Defects in HfO2 and Y2O3 on GaAs(001) with High Thermal Stability

Oxide defects in HfO
₂
and Y
₂
O
₃
on GaAs(001) are characterized by analyzing capacitance-voltage (C-V) hysteresis of metal-oxide-semiconductor capacitor (MOSCAP) under positive and negative stress fields. The C-Vs of Y
₂
O
₃
/GaAs have smaller hysteresis and flat-band voltage shift in both accumulation and depletion regimes. This indicates less shallow and deep traps for Y
₂
O
₃
, making this high-k oxide more suitable than HfO
₂
for GaAs passivation in terms of reliability.