HIGH-RESOLUTION X-RAY-DIFFRACTION CHARACTERIZATION OF SEMICONDUCTOR STRUCTURES

The high-resolution X-ray diffraction techniques, such as double-cryst al rocking curve and triple-crystal diffraction, have become essential tools in the semiconductor materials and devices laboratory. Quick an d non-destructive characterization is possible for basic layer paramet ers including layer composition, strain, mismatch and thickness. More sophisticated characterization of interface and quantum-well structure s with submonolayer resolution is possible with the help of kinematica l diffraction principles and diffraction profile simulation using the dynamical diffraction theory. These X-ray diffraction techniques are m aking it possible to correlate the structural properties to the epitax ial growth processes, to the electrical/optical properties and to the device performance. In this review article, I discuss some basic aspec ts of the instrument, simple determination of layer parameters, the dy namical and kinematical diffraction theories, and some recent results in the characterization of heterostructure interfaces and strained qua ntum-well devices. I also discuss the diffuse scattering analysis of b ulk semiconductors in the Bragg diffraction geometry. Interface analys is of the lattice-matched structures such as GaInAs/InP and AlGaAs/GaA s is discussed in terms of kinematical diffraction principles, namely the X-ray phase shift and the crystal truncation rod. Analysis of stra ined quantum wells is discussed using Bragg peak profile and Pendellos ung fringe profile. Diffuse scattering in bulk semiconductors is discu ssed in the context of the analysis theory, namely the rocking-curve p rofile and the radial intensity profile around a reciprocal lattice po int of the diffuse scattered X-rays due to such defects as dislocation loops and spherical defect clusters.