Pulsed anodic oxidation of GaAs for impurity-free interdiffusion of GaAs/AlGaAs quantum wells

The use of pulsed anodic oxidation of GaAs for impurity-free quantum well i nterdiffusion is demonstrated. The GaAs capping layer of a single GaAs/Al0. 3Ga0.7. As quantum well structure was oxidized and rapid thermal annealing (RTA) at 900 degreesC for 60 s was carried out to create atomic interdiffus ion, X-ray photoeletron spectroscopy was used to study the anodic oxide bot h before and after RTA, The defects created in oxidized p-GaAs epitaxial la yers were also studied using deep-level transient spectroscopy (DLTS), The possible mechanisms that generate excess gallium vacancies, V-Ga, during ei ther the anodic oxidation process or RTA to promote interdiffusion of the G aAs/AlGaAs quantum well are discussed. Copyright (C) 2000 John Wiley & Sons , Ltd.