Native oxide transport and removal during the atomic layer deposition of Ta2O5 on InAs(100) surfaces

Abstract

Atomic layer deposition (ALD) was used to deposit Ta2O5 on etched and native oxide-covered InAs(100) using pentakis dimethyl amino tantalum and H2O at 200–300 °C. The transport and removal of the native oxides during the ALD process was investigated using x-ray photoelectron spectroscopy (XPS). Depositions above 200 °C on etched surfaces protected the interface from reoxidation. On native oxide-covered surfaces, depositions resulted in enhanced native oxide removal at higher temperatures. The arsenic oxides were completely removed above 250 °C after 3 nm of film growth, but some of the As2O3 remained in the film at lower temperatures. Angle-resolved and sputter depth profiling XPS confirmed indium and arsenic oxide migration into the Ta2O5 film at deposition temperatures as low as 200 °C. Continuous removal of both arsenic and indium oxides was confirmed even after the deposition of several monolayers of a coalesced Ta2O5 film, and it was demonstrated that native oxide transport is a prevalent component of the interface “clean-up” mechanism.