Dislocation structure of the AlGaN/GaN/α-Al2O3 heterostructures epitaxial layers at doping GaN with С and Fe

Abstract

The aim of this work was to study the influence of the iron and carbon doping of the epitaxial GaN layer on sapphire on the growth features of epitaxial films and their dislocation structure. Investigation methods used were: mass spectroscopy of secondary ions, selective chemical etching on spherical sections, and also single-crystal diffractometry.It is shown that doping during growth of an epitaxial GaN layer with carbon can lead to a significant decrease in the dislocation density in epitaxial layers.It has been shown that for samples doped with iron, a decrease in the number of short dislocations located in the bulk of the structure is characteristic, but a large number of extended dislocations are generated contributing to the diffusion of iron into the working regions of heterostructures, which can adverselyinfluence on the electrical parameters of the structures. In the course of the work, a technique for determining the density of dislocations in epitaxial films was proposed using two schemes of selective etching of spherical thin sections, which makes it possible to determine the dislocation density distribution over the depth of epitaxial films.