The threading dislocations in films which had been grown onto Al2O3 substrates were studied by means of plan-view transmission electron microscopy. A pure edge dislocation, and a mixed dislocation with various degrees of screw component, could be distinguished by obtaining images near to, and far from, the <00•1> zone. The experimental results showed that some pure edge dislocations formed low-angle boundaries, while other pure edge dislocations and mixed dislocations were randomly distributed in the films. The randomly distributed dislocations resulted from the reaction of partial dislocations. On the other hand, partial dislocations formed in order to eliminate stacking disorder near to the film/substrate interface.

M.Hao, T.Sugahara, H.Sato, Y.Morishima, Y.Naoi, L.T.Romano, S.Sakai: Japanese Journal of Applied Physics - 2, 1998, 37[3A], L291-3