Effect of In-content on the misfit dislocation interaction in InGaAs/GaAs layers

Abstract

A previous published model (D. González, D. Araújo, G. Aragón, R. Garcia, Appl. Phys. Lett., 71 (1997) 2477) allows us to predict the plastic relaxation in the saturation regime of epitaxial layers. This model is in agreement with the experimental residual strain for In xGa 1− x As/ GaAs epilayers below 40% In-content. Above 40% In-content, the predicted values of residual strain become larger than the experimental one. This disagreement takes its origin in the change of growth mode that implies a transition from a 60 ° misfit dislocation (MD) network to a Lomer MD one. An almost complete relaxation can be reached by a Lomer MD network, which is not possible with 60 † MD networks. The difference between both kinds of networks comes from the repulsive interaction of 60 ° MD that inhibits the lattice relaxation.