AUGER SPUTTERING PROFILING OF AN AL0.3GA0.7AS/GAAS SUPERLATTICE GROWN BY MOLECULAR-BEAM EPITAXY

The layered structure, the composition of each layer and the interfacial sharpness in an Al0.3Ga0.7As/GaAs superlattice, grown by molecular beam epitaxy (MBE), have been studied by means of Auger depth profiling. In order to improve the depth resolution and then to reduce the uncertainty in measuring the interfacial sharpness, the Auger and argon ion beam sputtering parameters have been optimized and an ultimate depth resolution of 3.17 nm has been achieved using a differential pumping-type ion gun with a very low ion current. Under these conditions the layered structure and the abruptness of the change in composition at the interface between two thin adjacent layers has been well disclosed.