Thin Films on the Surface of GaAs, Obtained by Chemically Stimulated Thermal Oxidation, as Materials for Gas Sensors

Abstract

Semiconductor metal oxide films on the surface of gallium arsenide are obtained by chemostimulated oxidation under the influence of a Sb2O3 + Y2O3 composition. The chemical composition of the obtained films and the surface morphology are determined by EPXMA, IR spectroscopy, and AFM. The main components of the films are gallium and arsenic, which are in the oxidized state. The content of the chemical stimulator (Sb2O3) does not exceed 2%. Films obtained under the influence of composites 60% Sb2O3 + 40% Y2O3 and 80% Sb2O3 + 20% Y2O3 are characterized by the maximum surface roughness. The samples obtained in this work demonstrate n-type semiconductor properties in the temperature range of 20–400 °C. It is established that the obtained samples have a gas-sensitive response to NH3 and CO. The maximum value of the sensory signal appears for the samples obtained under the influence of compositions 80% Sb2O3 + 20% Y2O3, which are characterized by the most developed surfaces. The resulting films are selective to the studied gases—the difference in temperature for the maximum signal is 60 °C (200 °C for CO and 260 °C for NH3).