In-situ atomic layer deposition of tri-methylaluminum and water on pristine single-crystal (In)GaAs surfaces: electronic and electric structures

Abstract

The electronic structure of single-crystal (In)GaAs deposited with tri-methylaluminum (TMA) and water via atomic layer deposition (ALD) is presented with high-resolution synchrotron radiation core-level photoemission and capacitance-voltage (CV) characteristics. The interaction of the precursor atoms with (In)GaAs is confined at the topmost surface layer. The Ga-vacant site on the GaAs(111)A-2 × 2 surface is filled with Al, thereby effectively passivating the As dangling bonds. The As-As dimers on the GaAs(001)-2 × 4 surface are entirely passivated by one cycle of TMA and water. The presumed layerwise deposition fails to happen in GaAs(001)-4 × 6. In In0.20Ga0.80As(001)-2 × 4, the edge row As atoms are partially bonded with the Al, and one released methyl then bonds with the In. It is suggested that the unpassivated surface and subsurface atoms cause large frequency dispersions in CV characteristics under the gate bias. We also found that the (In)GaAs surface is immune to water in ALD. However, the momentary exposure of it to air (less than one minute) introduces significant signals of native oxides. This indicates the necessity of in situ works of high κ/(In)GaAs-related experiments in order to know the precise interfacial atomic bonding and thus know the electronic characteristics. The electric CV measurements of the ALD-Al2O3 on these (In)GaAs surfaces are correlated with their electronic properties.

Single-Crystal Y2O3 Epitaxially on GaAs(001) and (111) Using Atomic Layer Deposition

“…Also, no native oxides were detected, as examined using in-situ XPS and synchrotron radiation photoemission under the same transfer procedure [46]. The freshly MBE grown GaAs(001)-4 × 6 and GaAs(111)A-2 × 2 samples were in-situ transferred to the ALD reactor under UHV.…”

Microscopic Views of Atomic and Molecular Oxygen Bonding with epi Ge(001)-2 × 1 Studied by High-Resolution Synchrotron Radiation Photoemission

“…O 2 is introduced into the MBE chamber to compensate for the loss of oxygen from bombarding the oxide target upon the deposition of a high-κ dielectric oxide onto a Ge(001) wafer,. The partial pressure of O 2 is unreactive to the (In)GaAs substrates [35], but it is not entirely unaffected at the Ge substrate; the ALD is operating at a high pressure and it generates similar concerns for the oxygen residual. The established records of initial O 2 adsorption on Ge(001) have made their comments based on the very first work by Fukuda and Ogina two decades ago, who suggested that one of the dissociated O atoms of O 2 sits at the bridge site and the other sits at a backbond of the Ge-Ge dimer [34,36].…”

Atom-to-atom interaction of O2 with epi Ge(001)-2 × 1 in elucidating GeO x formation

“…Upon deposition of high-κ dielectric oxides onto a Ge(001) wafer, O 2 is introduced into the molecular beam evaporation chamber in order to compensate for the loss of oxygen from bombarding the oxide target. The partial pressure of O 2 is immune to the (In)GaAs substrates, 14) but not entirely unaffected at the Ge substrate; atomic layer deposition (ALD) operating at a high pressure generates similar concerns for the oxygen residual. Established records of the initial O 2 adsorption on Ge(001) have made their comments based on the very first work by Fukuda and Ogina (FO) two decades ago, who suggested that one of the dissociated O atoms of O 2 sits at the bridge site and the other at a backbond of the Ge-Ge dimer.…”