AES depth profile study of a GaAs/AlAs superlattice

The width of the interface between sublayers in a GaAs/AlAs superlattice was investigated using AES combined with Ar+ ion sputtering and chemical etching. The factors stipulating the experimental broadening of the interface width were estimated. The real interface width, determined for a GaAs/AlAs superlattice grown by metal organic chemical vapour deposition (MOCVD), did not exceed three AlAs lattice constants. The influence of the sputtering ion beam energy to the experimental interface width, caused by surface roughness, was investigated. It was demonstrated that combinations of the initial chemical etching or high-energy ion sputtering with further low-energy sputtering allowed deep sublayers to be investigated faster and without loss of depth resolution.