Initial etching of GaAs (001) during H2 plasma cleaning

Abstract

The initial etching of GaAs (001) during remote H2 plasma etching for oxide removal was examined using atomic force microscopy, coupled with in situ reflection high energy diffraction and Auger spectroscopy. Localized etching of the GaAs surface is particularly evident for etch temperatures below ∼650 K and leads to the formation of etch pits 5–10 nm deep and 20–50 nm in diameter. Etch pit formation was found to occur well before complete oxide removal. The development of etch pits is influenced by surface mis-cut steps, possibly due to increased hydrogen incorporation into the near surface at surface defects such as steps.