High-resolution double-axis X-ray topographic in situ measurements were made of the critical thickness at which misfit dislocations formed in strained layers of InGaAs which had been grown epitaxially onto (001) GaAs substrates. The critical thickness for formation of the initial fast B(g) misfit dislocations was found to be close to, but larger than, the predictions of the Matthews-Blakeslee model. The variation in the critical thickness, with Si doping, was modelled by including a Peierls stress in the force-balance equation for misfit dislocation motion. Only a very small change was observed in the critical thickness as a function of growth temperature. The inclusion of a temperature-dependent term in the Matthews-Blakeslee model indicated an activation energy of 0.3eV.

In situ X-Ray Topography Measurement of the Growth Temperature Dependence of the Critical Thickness of Epitaxial InGaAs on GaAs. B.K.Tanner, P.J.Parbrook, C.R.Whitehouse, A.M.Keir, A.D.Johnson, J.Jones, D.Wallis, L.M.Smith, B.Lunn, J.H.C.Hogg: Journal of Physics D, 2001, 34[SA], 109-13