In content dependence of pre-treatment effects on Al2O3/InxGa1−xAs MOS interface properties

We examine the electrical and physical properties of ALD Al
₂
O
₃
/In
_x
Ga
_1-x
As (x = 0.53, 0.7 and 1) MOS interfaces with (NH
₄
)S
_y
, BHF and HF pretreatment. It is found that, in higher In content (x), In
_x
Ga
_1-x
As MOS interfaces with BHF and HF cleaning exhibit better C-V characteristics and lower interface state density (D
_it
) than with (NH
₄
)Sy pretreatment. Also, amounts of arsenic oxides, evaluated from x-ray photoelectron spectroscopy (XPS), are found to increase in the higher In content In
_x
Ga
_1-x
As MOS interfaces with BHF and HF cleaning, suggesting that arsenic oxides can contribute to passivation of Al
₂
O
₃
/InGaAs MOS interface defects.