Use of a new type of atomic hydrogen source for cleaning and hydrogenation of compound semiconductive materials

This article describes a source of atomic hydrogen (AH) based on a reflected Penning are discharge with a hollow cathode and a self-heating electrode, designed for treating semiconductor materials with atomic hydrogen in technological processes. The source can readily be incorporated in industrial systems for thin-film deposition, ion implantation, and molecular beam epitaxy. In experiments on treatment of semiconductor structures the source was operated at a discharge operating voltage of 200 V and a current of 2 A. Measurements of the activation energy of AH etching have been preformed for GaAs (0.13 eV) and InP (0.19 eV) anode oxides and for a SiO2 film produced by chemical vapor deposition method (0.15 eV). The thickness of the native oxide layer has been investigated as a function of temperature and treatment time. The oxide film was completely removed in 1-2 min at a specimen temperature of T = 400 degrees C and in 3-5 min at T = 350 degrees C. It has been shown that when the AH cleaning of the GaAs surface and deposition of a metal film (AuGe, Ti, Ni) are accomplished in a unified vacuum cycle, no contaminant is present at the film-substrate interface. This, in particular, improves the characteristics of structures with a Schottky barrier. It has been found experimentally that the AH treatment of the GaAs surface reduces the rate of the subsequent oxidation of the surface in air. The AH source was also used for hydrogenation of the near-surface layers of semiconductor structures. The devices manufactured from the hydrogenized structures showed improved performance. (C) 1998 American Vacuum Society. [S0734-2101(98)09704-8].