MISFIT AND THREADING DISLOCATIONS IN GAAS ON VICINAL (110) SI

Misfit and threading dislocation morphologies and characteristics have been investigated in similar to 1 mu m thick GaAs films grown by mole cular beam epitaxy on (110) Si with an off-angle of 6 degrees toward t he [001] direction using a transmission electron microscope. The short and segmented misfit dislocations of 60 degrees- and 30 degrees- type are mainly oriented to one +/-[(1) over bar 10] and two [112] directi ons, respectively, near the interface regions between GaAs and Si. On the other hand, most of the observed threading dislocations are 60 deg rees-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 +/-[(1) over bar 10]-oriented misfit dislocations change into the [110]- and [110]-oriented threading dislocations, res pectively, on either one of four {111} planes during growth. The effec t of thermal annealing on the change of morphologies and density of th ese dislocations is also discussed.