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 smal l area X-ray photoelectron spectroscopy (XPS), the chemical compositio n 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 heter o-interface, have been studied. For a particular set of experimental c onditions, a calibration curve has been obtained for the aluminum cont ent, that shows a linear relationship between AES data and chemical co mposition deduced from both MBE growth parameters and double crystal d iffraction. This calibration curve has been used to determine the chem ical composition of a nominal Al0.3Ga0.7As/GaAs MQW. Furthermore, the abruptness of the change in composition at the interface between Al0.3 Ga0.7As and GaAs layers has been well characterized and an ultimate de pth resolution of 5 nm has been achieved for a sputtering ion energy o f 1 keV.