Impact of interfacial InAs layers on Al2O3/GaSb metal-oxide-semiconductor interface properties

We have systematically studied the impact of interfacial InAs layers on Al2O3/GaSb metal-oxide-semiconductor (MOS) interface properties. The interfacial InAs layers improved the capacitance versus voltage (C-V) curves of the Al2O3/GaSb MOS capacitors (MOSCAPs) fabricated by an ex-situ process. The minimum interface-trap density (Dit) value of an Al2O3/1.5-nm-thick InAs/p-GaSb MOSCAP is ∼6.6 × 1012 cm−2eV−1, which is reduced by ∼50% from that of ∼1.4 × 1013 cm−2eV−1 in an Al2O3/p-GaSb MOSCAP. Also, the interfacial InAs layers significantly improved the C-V curves of the Al2O3/n-GaSb MOSCAPs. The InAs layer can improve the Al2O3/GaSb MOS interface properties both in valence band side and in conduction band side.