High-Resolution Electron Backscatter Diffraction in III-Nitride Semiconductors

Abstract

The large and increasing interest in III-nitrides semiconductors lies in the wide range of useful applications that can be achieved, from high electron mobility transistors (HEMTs) to light emitting LEDs and lasers. However, the III-nitride materials are usually epitaxially grown on foreign substrates, which lead to the formation of a large number of dislocations and significant strain variations in the epitaxial layers that seriously affect the performance of devices based upon them. The acquisition of high resolution electron backscatter diffraction (EBSD) patterns in the scanning electron microscope (SEM) is a very powerful method for the microstructural characterization of crystalline materials. EBSD is well established as a technique capable of measuring elastic strains, lattice rotations, and defect density in metallic materials, but until recently, it has not had much uptake for characterization of semiconducting materials [1]. This is largely as a result of the angular resolution limit of ~0.5° (~10 -2 rads) of the conventional Hough-transformed analysis. The introduction of cross-correlation based analysis of EBSD patterns has seen a step change in the angular resolution to ~10