Interface State Density in Atomic Layer Deposited SiO2/ $\beta $ -Ga2O3 ( $\bar {2}01$ ) MOSCAPs

The interface state density (D
_it
) at the interface between β-Ga
₂
O
₃
(2̅01) and atomic layer deposited (ALD) SiO
₂
dielectric is extracted using Terman method and conductance method. The effect of the different surface treatments on the extracted D
_it
was also studied. It is observed that the extracted D
_it
of 6 × 10
¹¹
cm
^-2
eV
^-1
for the sample with no surface treatment is lower than hydrofluoric and hydrochloric acid treated samples. Low D
_it
sample shows narrow peak in the conductance method, suggesting a smooth interface. The extracted low D
_it
makes ALD SiO
₂
an attractive candidate for future Ga
₂
O
₃
power devices.