Interfacial Cleaning Effects in Passivating InSb with Al2O3 by Atomic Layer Deposition

Al 2 O 3 was deposited on InSb by atomic layer deposition using trimethyl-aluminum as the metal precursor. Most of the native oxides on InSb substrate were in situ cleaned away from the interface of Al 2 O 3 /Insb, except for a small amount of In 2 O 3 residual, after the deposition-of Al 2 O 3 . Moreover, a slight contamination of In 2 O 3 , In(OH) 3 , and nearly negligible Sb 2 O X was observed on the surface of AI 2 O 3 . The Al 2 O 3 films show a good insulating property (∼10 -9 to 10 -8 A/cm 2 within ± 4 V), and a transition from accumulation to depletion was displayed from the capacitance-voltage relation measured at 77 K.