An in situ examination of atomic layer deposited alumina/InAs(100) interfaces

Undoped InAs(100) wafers were either passivated with sulfur from a (NH(4))(2)S(x) solution or etched with NH(4)OH and then characterized with monochromatic x-ray photoelectron spectroscopy (XPS) before and after in situ deposition of Al(2)O(3) by atomic layer deposition. Sulfur passivation minimized oxidation. Trimethyl aluminum (TMA) exposure reduced trivalent indium and arsenic oxidation states. The In(1+) chemical state persisted while elemental arsenic remained at the Al(2)O(3)/InAs interface prior to TMA exposure and possibly a mixture of As-As and As-Al bonds were present afterwards. The In 3d(5/2) peak line shape from bulk InAs differed from previous XPS experiments on epitaxial In(x)Ga(1-x)As. (C) American Institute of Physics. [doi: 10.1063/1.3432749]