The degradation of lattice-matched In0.72Ga0.28As0.61P0.39/InP hetero-interfaces during Zn diffusion was investigated by using high-resolution transmission electron microscopy and Auger electron spectroscopy. Diffusion-induced intermixing of In and Ga across the GaInAsP/InP interface produced tensile stresses in the Ga-mixed InP side and compressive stresses in the In-mixed GaInAsP side. The effects of localized interfacial stresses upon the nucleation of misfit dislocations and upon their strain accommodation behavior were clearly revealed throughout the intermixed region, and reached several thousand Å on both sides of the interface. The interfacial strain was relaxed by the generation of paired dislocations, with anti-parallel Burgers vectors, which arose from the intermixed GaInAsP/GaInP interface. The dislocation morphologies revealed striking contrasts across the intermixed interface; involving stacking faults in the tensile layer and perfect dislocation tangles in the compressive layer. The dislocation lines were concentrated at the GaInAsP/GaInP interface and along misfit boundaries in the frontal areas of the intermixed region. A model was proposed, in order to explain the strain relaxation behavior in the intermixed region, which invoked an homogeneous nucleation mechanism and splitting of the paired dislocations from the intermixed interface.

H.H.Park, K.H.Lee, J.K.Lee, Y.T.Lee, E.H.Lee, J.Y.Lee, S.K.Hong, O.Kwon: Journal of Applied Physics, 1992, 72[9], 4063-72