This article is cited in 6 papers

Surface, interfaces, thin films

Development of the physicochemical properties of the GaSb(100) surface in ammonium sulfide solutions

M. V. Lebedev^a, T. V. L'vova^a, A. L. Shakhmin^b, O. V. Rakhimova^c, P. A. Dementev^a, I. V. Sedova<sup>a

a</sup> Ioffe Institute, St. Petersburg
^b Peter the Great St. Petersburg Polytechnic University
^c Saint Petersburg Electrotechnical University "LETI"

Abstract: Various conditions of passivation of the GaSb(100) surface by ammonium sulfide ((NH$_4$)$_2$S) solutions depending on the solution concentration, solvent, and treatment time are investigated by X-ray photoelectron spectroscopy and atomic-force microscopy. It is shown that treatment of the GaSb(100) surface by any (NH$_4$)$_2$S solution leads to removal of the native oxide layer from the semiconductor surface and the formation of a passivating layer consisting of various gallium and antimony sulfides and oxides. The surface with the lowest roughness (RMS = 0.85 nm) is formed after semiconductor treatment with 4% aqueous ammonium sulfide solution for 30 min. Herewith, the atomic concentration ratio Ga/Sb at the surface is $\sim$2. It is also found that aqueous ammonium sulfide solutions do not react with elemental antimony incorporated into the native-oxide layer. The latter causes a leakage current and Fermi-level pinning at the GaSb(100) surface. However, a 4% (NH$_4$)$_2$S solution in isopropanol removes elemental antimony almost completely; herewith, the semiconductor surface remains stoichiometric if a treatment duration is up to 13 min.

Received: 23.01.2019
Revised: 08.02.2019
Accepted: 12.02.2019

DOI: 10.21883/FTP.2019.07.47866.9070

 English version: Semiconductors, 2019, 53:7, 892–900

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