Determination of microdistortion components and their application to structural characterization of HVBE GaN epitaxial layers

The dislocation structure of hydride vapour phase epitaxial thick GaN layer s grown on sapphire is studied by analysis of the microdistortion tenser co mponents. Symmetrical reflections (including reflections from planes formin g large angles with the basal plane) with two modes of scanning (theta and theta -2 theta) in two geometries (Bragg and Lane) are used to obtain the t enser components. The instant connections between the tenser components and major dislocation types are specified. Different types of dislocation dist ributions have been identified in the thick GaN films grown on sapphire wit hout and with undoped and Si-doped metal-organic chemical vapour deposited templates.