Features of Oxidation of Ar+-Ion-Irradiated GaAs

• Published in: Surface investigation, x-ray, synchrotron and neutron techniques x-ray, synchrotron and neutron techniques, 2022-10, Vol.16 (5), p.884-889
• Main Authors: Solonitsyna, A. P., Makarevskaya, E. A., Novikov, D. A., Mikoushkin, V. M.
• Format: Article
• Language: English
• Subjects: Argon ions; Arsenic; Chemical composition; Chemistry and Materials Science; Defects; Diffusion layers; Diffusion length; Enhanced diffusion; Materials Science; Oxidation; Radiation; Radiation damage; Radiation effects; Room temperature; Surfaces and Interfaces; Thickness; Thin Films
• ISSN: 1027-4510; 1819-7094
• DOI: 10.1134/S1027451022050342

The features of oxidation of the surface of GaAs irradiated by low-energy Ar + ions is considered based on elemental and chemical-composition analyses, calculations of the concentration profiles for radiation-induced defects, and estimations of radiation-enhanced diffusivities and diffusion lengths. The native oxide layer is revealed to be highly enriched with Ga (by a factor of 1.5) due to the radiation-enhanced diffusion of elemental arsenic through vacancy defects even at room temperature. Elemental arsenic emerging at the interface with the oxide layer moves to a deeper radiation-damaged layer and fills vacancies there. At irradiation doses of Q > 3 × 10 14 cm –2 , which are sufficient for removal of the oxide layer with 3-keV Ar + ions, elemental arsenic leaves the oxide layer within one hour, and the diffusion length reaches the thickness of the radiation-damaged layer within one day. The total number of vacancies in the radiation-damaged layer is enough to absorb all elemental arsenic formed during oxidation. The considered radiation-enhanced diffusion can be used to remove elemental arsenic, which is known to form nonradiative recombination centers quenching the luminescence of the underlying bulk layer, from the oxide layer.