Crystallography and Microstructure of Thin Films Studied by X-Ray and Electron Diffraction

摘要

For the characterization of thin films conventional x-ray and electron diffraction techniques have been modified and dedicated new techniques have been developed recently with special emphasis being laid on unattended operation. They enable the accurate measurement of lattice parameters, crystallographic orientations of individual grains, crystal texture, lattice strain and residual stress. The analysis of local crystal texture in particular is required for the understanding, for example, of anisotropic material properties, nucleation, recrystallization, plastic deformation and failure mechanisms. X-ray diffraction is still the standard technique for averaging over macroscopic specimen areas. On a grain-specific scale crystal texture analysis and phase discrimination are mainly performed by electron diffraction involving the SEM or TEM by interpreting backscatter or transmission Kikuchi patterns. Pole figures of small areas are obtained from thin foils in SAD or from bulk surfaces in RHEED mode of the TEM. A graphical representation of spatial distribution of grain orientations, texture, and lattice strain in the specimen surface is obtained with pseudo-color maps.