X-RAY TOPOGRAPHY AND DIFFRACTOMETRY OF STRAINED LAYER HETEROEPITAXIAL STRUCTURES

The accurate measurement of lattice strain in heteroepitaxial semiconductor layers is fundamental to the development of electronic devices, since it is often the structural properties of a material which limit its range of application in this type of structure. High-resolution x-ray diffraction techniques provide some of the assessment procedures for measuring the state of strain in these often complex structures; their use over recent years is briefly reviewed. The advantages and limitations of x-ray diffractometry and topography for measuring the onset and progress of lattice relaxation are discussed and demonstrated with examples from III-V material systems. The application of these techniques to mapping the homogeneity and defect structure in highly mismatched II-VI epitaxial systems is also described.