The  in situ  detection of the strain relaxation which arose from misfit dislocation formation was studied, during the molecular beam epitaxial growth of InGaAs on GaAs(001), by using diffuse light-scattering techniques. An increase in the scattering intensity, that was associated with the roughening that arose from dislocations, was detected above a certain thickness. However, the characterization of quenched samples by using transmission electron microscopy, atomic force microscopy and X-ray diffraction methods showed that this onset was associated with a roughening that arose from preferential growth which was associated with misfit dislocations, and not from the initial onset of dislocation formation. Atomic force microscopy, optical and soft X-ray light-scattering data were compared, and this showed that the detection of lines of steps which revealed the first misfit dislocations that arose from strain relaxation was lost in background noise that arose from the initial roughness of the substrate buffer surface.

K.L.Kavanagh, R.S.Goldman, C.Lavoie, B.Leduc, T.Pinnington, T.Tiedje, D.Klug, J.Tse: Journal of Crystal Growth, 1997, 174, 550-7