High Schottky barriers on and thermally induced processes at the Au– GaAs(110) interface

Abstract

New photoemission measurements show higher Schottky barrier heights (≳1.3 eV) on atomically clean GaAs(110) surfaces at a Au coverage of about 25 monolayers. It is suggested that this effect is due to the movement of Au into the semiconductor; at room temperature it creates acceptor states near the valence band maximum (VBM) that cause the Fermi level at the surface (Efs ) to move close to the VBM. We found that heating of the GaAs(110) surface (above 100 °C) covered with a small amount of Au (0.2 monolayer) causes Efs to move back to its original position (on the clean surface before Au deposition). The heating process is found to greatly inhibit the formation of large barrier heights due to the removal of defect states from the surface region.

Forensic science

“…Synchrotron UPS measurements of the initial stages of Au, Ge, and Ga deposition on ALAs(llO) and -(100) surfaces have been made; Au produces a larger initial dissociation and As outdiffusion than reported for Au on GaAs, however, the net Au-AlAs interdiffusion is smaller than for GaAs (73). UPS measurements have also shown high Schottky barrier heights (>1.3 eV) for GaAs(llO) surfaces covered with about 25 monolayers of Au (726). The initial growth of Au on GaAs-(001)-c(4 X 4) was studied by AES and RHEED; for more than 0.4 monolayer there is rapid intermixing and a tendency of As accumulation at the surface (27).…”

X-Ray absorption spectroscopy under conditions of total external reflection: application to the structural characterisation of the Cu/GaAs(100) interface

“…The values reported in parentheses refer to the variations in the parameters obtained for M = Cu, As or Ga.discussed above seems to preclude the presence of Cu cations at these larger distances. Additionally, as the first Cu-M (M = Ga, As or Cu) correlation is calculated at a distance (ca 3…”

Room temperature adsorption of au on cleaved GaAs (110)

“…A few studies have been devoted already to the Au/GaAs (110) system. In particular, the group at Stanford University [4-7] using UV and X-ray photoemission spectroscopies proposed at rirst an interface formation dominated by intermixing, even at room temperature, up to the highest coverages (7 x 1016 atoms cm-2), and accompanied by the development of a band bending which could reach 1.3 eV on an n-type GaAs substrate [6]. Recently, Pan et al [8] have not excluded a non laminar Au film growth; if it is indeed the case, the experimental data become much more difficult to interpret since the surface is then inhomogeneous.…”