Effects of Surface Treatments on Interfacial Self-Cleaning in Atomic Layer Deposition of Al2O3 on InSb

The atomic layer deposition (ALD) of Al 2 O 3 using trimethylaluminum (TMA) as a metal precursor on an InSb substrate with or without surface pretreatments was investigated. It was found that both in situ TMA/Ar purging (half-ALD cycle) and ex situ CP4A (HNO 3 HF:CH 3 COOH:H 2 O = 2:1:1:10) chemical etching can remove the native oxides on InSb before ALD of Al 2 O 3, and lead to a native-oxides-free Al 2 O 3 /InSb structure. Characteristics of current density-voltage and capacitance-voltage were also investigated to evaluate the insulative and interface quality in a Pt/Al 2 O 3 /Insb metal-oxide-semiconductor structure.