Chih-Yu Chang

In content dependence of pre-treatment effects on Al 2 O 3 /In x Ga 1−x As MOS interface properties

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