Physicochemical properties of the surface and near-surface region of epitaxial n-GaAs layers modified by atomic hydrogen

Changes in the static electrical parameters of the Au-GaAs Schottky barriers in the (n-n ⁺)-GaAs structures treated with atomic hydrogen are closely related to modification of the chemical properties of the surface layers in these structures, including changes in the rate of n-GaAs etching in a DMF-monoethanol amine (1:3) solution, in the electrochemical deposition rate and the structure of the resulting Au layer, and in the degree of passivation of linear defects emerging on the surface. The unprotected surface of epitaxial n-GaAs(100) layer exhibited virtually no etch pits upon the treatment in atomic hydrogen at 100°C. For n-GaAs protected with a 50-Å-thick SiO₂ film, a drop in the etching rate and a considerable decrease in the number of etch pits, as well as a decrease in the thickness of electrochemically deposited gold layer and a change in is structure, were observed for the samples treated in atomic hydrogen at all temperatures in the range studied (100–400°C).