Characterization of interface properties of Al₂O₃/n-GaSb and Al₂O₃/InAs/n-GaSb metal-oxide-semiconductor structures

Abstract The interfacial InAs layers can improve the MOS interface properties of n-type GaSb (n-GaSb) MOS capacitors with Al 2 O 3 insulating layers deposited by an ex-situ atomic-layer deposition (ALD) process. The n-GaSb MOSCAPs show the capacitance response in the accumulation region at room temperature (R.T.), but they did not show the response with any low frequency at 100 K, indicating the quite high interface trap density (D it ). On the contrary, the n-GaSb MOSCAPs with the interfacial InAs layers show the sufficient accumulation responses at 100 K as well as R.T., indicating the lower D it . The 1.5-nm-thick InAs/n-GaSb MOSCAP with ALD-Al 2 O 3 deposited at 150 ºC exhibited relatively low D it of 2.6×10 13 cm -2 eV -1 , and the 2.5-nm-thick InAs/n-GaSb MOSCAP with ALD-Al 2 O 3 deposited at 300 ºC exhibited low D it of 2.6×10 12 cm -2 eV -1 , while the 2.5-nm-thick InAs layers can induce the delay of the response of electrons with the high frequency measurements at low temperature.