Effect of surface V2O5 nanolayers on the thermal oxidation kinetics of GaAs and the composition and morphology of resulting films

Abstract

Vanadium(V) oxide, V2O5, produces a well-defined chemical stimulation effect and can exhibit both oxygen-transfer and catalytic behavior in the thermal oxidation of III–V semiconductors. Applying V2O5 gel to the surface of GaAs is a mild surface modification method in which there is no interaction between the chemical stimulator layer and semiconductor substrate before thermal oxidation. Here, we describe the kinetics and mechanism of the thermal oxidation of VxOy/GaAs heterostructures produced by applying V2O5 gel from aerosol to the surface of the semiconductor and the composition and surface morphology of the resulting oxide films. The oxidation of the heterostructures follows an oxygen transfer mechanism, which is evidenced by the fact that there is no regeneration of vanadium in the oxidation state 5+ (X-ray diffraction data), as well as by the kinetic parameters of the process. According to X-ray diffraction data, the films contain vanadium(IV) oxide, gallium and arsenic oxides, and gallium arsenate, which allows their optical constants to be adequately described by the Cauchy dispersion formula and enables precision ellipsometric measurements. The thermal oxidation of VxOy/GaAs heterostructures produces films with a roughness height no greater than 57 nm.