Desorption of ultraviolet-ozone oxides from InP under phosphorus and arsenic overpressures

The thermal desorption of ultraviolet-ozone oxide on InP substrates prepared for molecular-beam epitaxy has been performed with overpressures of P2, As2, and As4. Surface analysis using reflection high-energy electron diffraction, Auger electron spectroscopy, and x-ray photoelectron spectroscopy and thermodynamic calculations indicate that thermal desorption proceeds via a reaction between the oxide and atomic phosphorus from the substrate to produce volatile phosphorus oxides such as P2O3. The overpressure species serves to stabilize the substrate against surface dissociation once the oxide is removed. In the case of an arsenic overpressure the desorption of the final monolayer of oxide is slowed, relative to the case of phosphorus overpressure, due to the formation of InAs.