A transmission electron microscopic study was made of the effects of post-growth annealing upon the movement and rearrangement of 2 different groups of misfit dislocation in molecular beam epitaxially grown GaAs on tilted (3 towards [110]) Si(001) substrates. The group-I misfit dislocations exhibited a cross-grid structure which ran along two <110> directions at the interface and formed already in small islands of 20 to 30nm in size. The spacing of about 9.5nm between the dislocations along each <110> direction was constant throughout all of the growth stages from 10nm to 3 of GaAs, although the cross-grid pattern became clearer and more regular during annealing. On the other hand, the group-II misfit dislocations had short and segmented structures which lay approximately along <110> directions. These were considered to be related to threading dislocations. They were very mobile and gradually became rearranged, with their length along <110> directions near to the interface, as the annealing temperature was increased. The group-I and group-II misfit dislocations were thought to be generated by stresses that were caused by the lattice misfit and thermal expansion misfit between GaAs and Si, respectively.

M.Tamura, T.Yodo, T.Saitoh, J.Palmer: Journal of Crystal Growth, 1995, 150[1-4], 654-60