Dislocation motion in GaAs/Al<inf>x</inf>Ga<inf>1-x</inf>As structures

Dislocations have been made to move through different compound semiconductor epilayer structures by deformation at 320 °C and have then been examined by transmission electron microscopy. The interaction between the dislocations and the GaAs/AlxGa1-xAs interface is shown to depend on the thickness of the AlxGa1-xAs layer. Dislocations are pinned at the interface and, for the MOCVD-grown material, within the AlxGa1-xAs layer. Dislocation dipoles, some of which are faulted dipoles, are then pulled out and lie preferentially along the heterojunction. It is emphasized that these dipoles, which may be important in device degradation, form as a result of dislocation glide and not dislocation climb.