XPS STUDY OF THE INXGA1-XAS GAAS SUPERLATTICE

Strained InxGa1-xAs/GaAs superlattices have been grown on GaAs(100) su bstrates using a metal-organic chemical vapour deposition (MOCVD) appa ratus. Fabricated heterostructures have been investigated by the selec ted area XPS depth profiling technique. The measurements have been car ried out using optimized Ar+ ion sputtering conditions. The width of t he heterointerfaces has been studied after correction of the experimen tal profiles (In3d5/2, Ga2p3/2 and Auger Ga LMM, In MNN peaks) for the influence of electron escape depth. The linear dependence of depth re solution DELTA(z) on the sputtering depth, caused by sputtering induce d surface roughening, is determined from experimental profiles. The in itial depth resolution DELTA(z) almost-equal-to 3 nm is degraded to DE LTA(z) almost-equal-to 8 nm at depth z almost-equal-to 100 nm. Quantit ative depth profiles of the investigated heterointerfaces are derived using calibrated elemental sensitivity factors and ion sputtering rate s. The results are found to be in good agreement with X-ray diffractom etry and transmission electron microscopy data.