Threading dislocation density reduction in two-stage growth of GaN layers

A theoretical approach is proposed to reduce the density of threading dislocations (TDs) in (0001) oriented growth of GaN layers. The approach can be realized by repeated stages of growth surface roughening (stage 1) and flattening (stage II). Fundamentals of the approach include the formation of a dislocation redirection layer with inclined TDs at stage I and enhanced reactivity among inclined TDs in a dislocation reaction layer at stage II. A reaction-kinetics model is applied for the quantitative prediction of TD density reduction which can be achieved as a result of the two-stage growth technique. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.