Self-cleaning and surface recovery with arsine pretreatment in ex situ atomic-layer-deposition of Al2O3 on GaAs

Annealing native oxide covered GaAs samples in Arsine(AsH3) prior to atomic-layer-deposition of Al2O3 with trimethyaluminum (TMA) and isopropanol (IPA) results in capacitance-voltage (C-V) characteristics of the treated samples that resemble the superior C-V characteristics of p-type GaAs grown by an in situ metal-organic chemical vapor deposition process. Both TMA and IPA show self-cleaning effect on removing the native oxide in ex situ process, little evidence of a native oxide was observed with high resolution transmission electron microscopy at the Al2O3/GaAs interface. The discrepancy in the C-V characteristics was observed in in situ p- and n-type GaAs samples.