QUANTITATIVE-ANALYSIS OF ALXGA1-XAS/GAAS MULTIQUANTUM WELLS BY MEANS OF AES DEPTH PROFILING AND SMALL AREA XPS

By means of Auger electron spectroscopy (AES) depth profiling and small area X-ray photoelectron spectroscopy (XPS), the chemical composition of the AlxGa1-xAs layer in a series of reference AlxGa1-xAs/GaAs (0.15 <x< 0.40) multiquantum wells (MQW) and the sharpness of the hetero-interface, have been studied. For a particular set of experimental conditions, a calibration curve has been obtained for the aluminum content, that shows a linear relationship between AES data and chemical composition deduced from both MBE growth parameters and double crystal diffraction. This calibration curve has been used to determine the chemical composition of a nominal Al0.3Ga0.7As/GaAs MQW. Furthermore, the abruptness of the change in composition at the interface between Al0.30Ga0.7As and GaAs layers has been well characterized and an ultimate depth resolution of 5 nm has been achieved for a sputtering ion energy of 1 keV. © 1993.