A series of AlN/GaN strained multi-layers having various thicknesses was grown at low or high temperatures by using alternating supplies of trimethylaluminium and NH3, or trimethylgallium and NH3. Transmission electron microscopic observations showed that uniform AlN/GaN superlattices and multi-layers were obtained at high and low temperatures. These AlN/GaN multi-layers were observed to block the threading dislocations effectively for certain thicknesses and growth temperatures. The AlN/GaN (5nm/5nm) strained multi-layers which were deposited, at 1050C, right above the low-temperature AlN buffer layers appeared to reduce the density of threading dislocations in the subsequently-grown high-temperature GaN film. In particular, the insertion of low-temperature pseudomorphic AlN/GaN strained multi-layers inside the high-temperature GaN film stopped 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