Summary
Interface intermixing of highly strained heterostructures was investigated using high-resolution double-crystal X-ray diffractometry combined with computer simulations. A method of modelling imperfections in semiconductor heterostructures was introduced to extract information from simulated and measured data in a fast and objective manner. The key steps of this method are i) the sensitivity analysis of experimental diffraction curves with respect to imperfections, and ii) the development of objective error criteria. The applicability of this method is demonstrated using highly strained [(InAs/GaAs)12/InGaAs]9 superlattices grown by molecular beam epitaxy (MBE) on InP substrates. The result of the modelling process enables a quantitative and objective determination of the intermixing at InAs/GaAs interfaces in relation to the MBE growth parameters which can be transferred to any other laboratory.