A number of reports have suggested that InGaAs/GaAs (111)B strained layer epitaxy has the prospect of reaching a higher critical layer thickness than that which could be achieved for (001) substrates. This has motivated a study of the relaxation mechanism of InGaAs/GaAs (111)B quantum wells with high In contents (0.12 to 0.35). Transmission electron microscopy has revealed the existence of a different misfit dislocation configuration for high In contents (above 0.25), which did not seem to have been reported previously. For such compositions, plastic relaxation takes place through a polygonal network of misfit dislocations, which have Burgers vectors in the interface plane. The origin of this network was an unusual dislocation source that occurred through the formation of a three-pointed star-shaped configuration. The characteristics of this misfit dislocation network, which has a higher misfit relieving component and a glide plane coincident with the interface plane, imply a reduction of the previous critical layer thickness estimates for high In content InGaAs/GaAs (111)B heterostructures. However, it was observed that none of the (111)B samples showed evidence of a transition to a three-dimensional growth mode, which represents a significant advantage compared to the behavior of high In content quantum wells on (001) substrates.

Strain Relaxation Behavior of InxGa1–xAs Quantum Wells on Vicinal GaAs (111)B Substrates. M.Gutiérrez, D.González, G.Aragón, R.García, M.Hopkinson, J.J.Sánchez, I.Izpura: Applied Physics Letters, 2002, 80[9], 1541-3