Chinese Acad Sci, Inst Phys, Beijing 100080, Peoples R China
; Beijing Synchrotron Radiat, Inst High Energy Phys, Beijing 100039, Peoples R China
The effect of lateral oxidation on microstructures of the GaAs/AlAs/GaAs heterostructure was studied by x-ray specular reflectivity, nonspecular scattering and diffraction. The GaAs/Al2O3/GaAs multilayer was obtained after oxidation of the GaAs/AlAs/GaAs sample. The results show that, before oxidation, there are two 40-Angstrom-thick intermixing layers, one located between the AlAs sublayer and the GaAs substrate, and the other between the AlAs sublayer and the upper GaAs sublayer. After oxidation, these two intermixing sublayers disappear. The AlAs was oxidized into amorphous Al2O3 totally. The surface and interface roughnesses of the sample also decrease after oxidation.