An investigation was made of the generation of threading dislocations and the relaxation of the compressive strain in the GaN/sapphire (00▪1) grown by metalorganic chemical vapor deposition. With decreasing growth pressure, the a-axis lattice constant of GaN film and the width of the (002) and the (101) rocking curve increased. This indicated that the density of threading dislocations in GaN epilayers increased with the lattice constant a of GaN film. The fact that the width of the (101) rocking curves increased much more than that of the (002) rocking curve indicated that the residual strain in GaN on sapphire reduces mainly by generating the edge-type TDs.

Growth Pressure Dependence of Residual Strain and Threading Dislocations in the GaN Layer. S.N.Lee, J.K.Son, H.S.Paek, T.Sakong, W.Lee, K.H.Kim, S.S.Kim, Y.J.Lee, D.Y.Noh, E.Yoon, O.H.Nam, Y.Park: Physica Status Solidi C, 2004, 1[10], 2458-61