MODELING INTERMIXING OF SHORT-PERIOD STRAINED-LAYER SUPERLATTICES BY MEANS OF X-RAY-DIFFRACTION ANALYSIS

Intermixing of an (InAs)(n)/(GaAs)(m), short period strained layer sup erlattice (SPSSL) is analyzed. Lattice matched (n approximate to m) an d indium rich (n > in) superlattices have been prepared by molecular b eam epitaxy in order to provide a ternary InxGa1-xAs channel in InP-HF ET with a reduced alloy scattering as theoretically predicted. For the optimization the interface intermixing of highly strained heterostruc tures was investigated using high-resolution double-crystal X-ray diff ractometry combined with computer simulations. A method of modelling i mperfections in semiconductor heterostructures was introduced to perfo rm the fit between the simulated and measured data in an objective man ner. The key steps of this method are (i) the sensitivity analysis of experimental diffraction curve details with respect to imperfections, and (ii) the development of objective error criteria. The result of th e modelling process enables a quantitative and objective determination of the intermixing at InAs/GaAs interfaces in relation to the molecul ar beam epitaxy OL?BE) growth parameters. (C) 1997 Elsevier Science S. A.