Investigation of arsenic and antimony capping layers, and half cycle reactions during atomic layer deposition of Al2O3 on GaSb(100)

Abstract

In-situ monochromatic x-ray photoelectron spectroscopy, low energy electron diffraction, ion scattering spectroscopy, and transmission electron microscopy are used to examine the GaSb(100) surfaces grown by molecular beam epitaxy after thermal desorption of a protective As or Sb layer and subsequent atomic layer deposition (ALD) of Al2O3. An antimony protective layer is found to be more favorable compared to an arsenic capping layer as it prevents As alloys from forming with the GaSb substrate. The evolution of oxide free GaSb/Al2O3 interface is investigated by “half-cycle” ALD reactions of trimethyl aluminum and deionized water.