GAAS SURFACE OXIDATION AND DEOXIDATION USING ELECTRON-CYCLOTRON RESONANCE OXYGEN AND HYDROGEN PLASMAS

We have used x-ray photoelectron spectroscopy to investigate electron cyclotron resonance oxygen plasma oxidation and hydrogen plasma deoxidation of GaAs surfaces. Experimental evidence shows that ECR oxidation at room temperature forms a stoichiometric oxide layer that is primarily composed of As2O5 and Ga2O3. A hydrogen plasma is shown to clean GaAs surfaces and recover surface order, even at room temperature. Sample heating (200-300-degrees-C) expedites the removal of Ga2O3 and improves surface order. In addition, no significant differences in oxidation and deoxidation were observed for sample biasing, either positively or negatively.