Assessment of lattice strain, rotation and dislocation content using electron back-scatter diffraction

Abstract

Cross-correlation based analysis methods have been developed for electron back scatter diffraction (EBSD) patterns that improve the angular sensitivity to ∼10-4 rads. This enables EBSD to be used to study the much smaller misorientations and even local elastic strain fields that are typical in semiconducting materials. Mapping of the lattice rotations and elastic strain variations provides sufficient detail for quantitative analysis of the threading dislocation density through the Nye tensor. The analysis will be briefly described and applications given to GaN and Si/SiGe based systems. Measurements of tilt, twist and elastic strain variations in GaN layers on basal plane sapphire will be reported and compared to results for some epitaxial lateral over grown (ELOG) GaN samples. The effects of misfit interfacial dislocations on the spatial distribution of the full strain and rotation tensors in a partially relaxed SiGe layer will also be shown.