Nonconservative formation of left-angle 100 right-angle misfit dislocation arrays at In0.2Ga0.8As/GaAs(001) interfaces during post-growth annealing

Transmission electron microscopy is applied to investigate the effect of annealing on misfit dislocations in an In0.2Ga0.8As/GaAs(001) heterostructure. In as-grown samples, an orthogonal array of 60 degree dislocations along left-angle 110 right-angle directions is observed in the interface. During annealing, the 60 degree dislocations along left-angle 110 right-angle directions are bent from left-angle 110 right-angle directions toward left-angle 100 right-angle directions. The process represents a new strain relaxation mechanism in semiconductor heterostructures. As the dislocation segments along left-angle 100 right-angle can relieve the strain more effectively than 60 degree dislocations, we propose that the dislocations move nonconservatively in or near the interface by diffusion along the dislocation cores or in the heterointerface