Misfit and threading dislocations in GaAs on vicinal (110) Si

Abstract

Misfit and threading dislocation morphologies and characteristics have been investigated in ∼ 1 μm thick GaAs films grown by molecular beam epitaxy on (110) Si with an off-angle of 6° toward the [001] direction using a transmission electron microscope. The short and segmented misfit dislocations of 60°- and 30°-type are mainly oriented to one ±[1̄10] and two 〈112〉 directions, respectively, near the interface regions between GaAs and Si. On the other hand, most of the observed threading dislocations are 60°-type dislocations along the 〈110〉 direction and the [110] growth direction on inclined {111} planes together with screw-type threading dislocations running parallel to the [110] direction. It is considered that the 〈112〉- and ±[1̄10]-oriented misfit dislocations change into the [110]- and 〈110〉-oriented threading dislocations, respectively, on either one of four {111} planes during growth. The effect of thermal annealing on the change of morphologies and density of these dislocations is also discussed.