Study of GaAs oxidation in the low-current Townsend discharge

An anodic oxidation of GaAs substrates in a non-self-sustained low-current dc Townsend discharge is investigated. The process is carried out at the room temperature in a three-electrode microreactor filled by 98%Ar + 2%O₂ gas mixture. Investigation of the oxidation kinetics indicates that the formed oxide is characterized by a high resistivity, ρ ∼ 10¹¹ Ω·cm. It is demonstrated the application of the method for formation of oxide films with dimensions of tens of microns, which thickness is on the nanometer scale. Examination of the "GaAs substrate - oxide layer" interface using the high resolution transmission electron microscopy has revealed that the oxide is characterized by the amorphous structure. (paper)