A theoretical approach was proposed to reduce the density of threading dislocations in (0001) oriented growth of GaN layers. The approach could be realized by repeated stages of growth surface roughening (stage I) and flattening (stage II). Fundamentals of the approach include the formation of a dislocation redirection layer with inclined threading dislocations at stage I and enhanced reactivity among inclined threading dislocations in a dislocation reaction layer at stage II. A reaction-kinetics model was applied for the quantitative prediction of threading dislocation density reduction which could be achieved as a result of the two-stage growth technique.

Threading Dislocation Density Reduction in Two-Stage Growth of GaN Layers. V.E.Bougrov, M.A.Odnoblyudov, A.E.Romanov, T.Lang, O.V.Konstantinov: Physica Status Solidi A, 2006, 203[4], R25-7