EBSD measurements of elastic strain fields in a GaN/sapphire structure

An elastic strain field of the heteroepitaxial GaN layer grown on the sapphire substrate, containing a buffer interlayer, was measured using the electron backscatter diffraction (EBSD). Pattern qualities, Hough transforms and small misorientations of Kikuchi bands on EBSD patterns, as strain sensitive parameters and referred to diffraction intensities, were performed to evaluate the elastically distorted region within the sample. The elastic strain gradient parallel to the growth direction of GaN epilayers was mapped and a strain range from 100 nm to 200 nm was detected.