A series of AlN/GaN strained multi-layers of various thicknesses were grown at low or high temperatures using an alternating supply of trimethylaluminum and NH3 or trimethylgallium and NH3. Transmission electron microscopy showed that uniform AlN/GaN superlattices and multi-layers were obtained at high and low temperatures. These AlN/GaN multi-layers were found to block the threading dislocations effectively at certain thicknesses and growth temperatures. Strained AlN/GaN (5nm/5nm) multi-layers, deposited at 1050C right above low-temperature AlN buffer layers, appeared to reduce the density of threading dislocations in subsequently grown high-temperature GaN films. The insertion of low-temperature pseudomorphic AlN/GaN strained multi-layers into the high-temperature GaN film halted the propagation of threading dislocations very efficiently.

Influence of AlN/GaN Strained Multi-Layers on the Threading Dislocations in GaN Films Grown by Alternate Supply of Metalorganics and NH3. J.R.Gong, C.L.Yeh, Y.L.Tsai, C.L.Wang, T.Y.Lin, W.H.Lan, Y.D.Shiang, Y.T.Cherng: Materials Science and Engineering B, 2002, 94[2-3], 155-8