Defect characteristics of Be⁺-implanted GaAs/AlAs heterostructures: effect of annealing

The effect of implantation of Be ions into GaAs/AlAs heterostructures at room temperature and liquid nitrogen temperature is investigated. Implantation at room temperature gives dislocation loops at the first interface, well short of the projected range maximum, while low temperature implants give twinning. Twinning could be removed by annealing at 900 degrees C (20 minutes) with no interdiffusion of Ga and Al, whereas the dislocation networks are found to enhance intermixing. Be concentrations are low enough to prevent Be-induced intermixing.