Depth profiling of InxGa1-xAs/GaAs superlattice

The width of the interfaces between adjacent sublayers in an InxGa1-xAs/GaAs superlattice grown by MBE was studied by means of small-area XPS combined with Ar+ ion sputtering. An experimental depth resolution of about 4 nm has been achieved in the profiles of the peaks of X-ray-excited photoelectrons and Auger electrons. A growth asymmetry of InxGa1-xAs/GaAs and GaAs/InxGa1-xAs interfaces has been detected in the obtained depth profiles. Only a negligible broadening of the heterointerfaces was observed up to the profiling depth of about 200 nm. The influence of casual effects of the ion sputtering on the experimental interface width is discussed briefly.