Abstract
The misfit stresses of metallorganic chemical vapor deposition grown heterostructure wafers were determined and their effects on the modulated microstructures of epilayer were investigated. Lattice mismatches were measured using {511}asymmetric and (400) symmetric x‐ray reflections. Elastic strains were obtained from the parallel mismatches and were used for determining the misfit stresses. Transmission electron microscopy results showed the presence of the modulated microstructures (spinodal decomposition) in the epilayer. It was found that the modulation periodicity varies with the lattice mismatches. To investigate this observation, the interaction elastic energy induced by misfit stress was derived and used to explain the experimental results. Good agreement was obtained between the measured and calculated modulation wavelength. Also, contributions from the composition and misfit stress to variation of modulation periodicity were separated out, and the misfit stress was found to have the larger contribution. Thus, it is concluded that the interfacial coherency and misfit stress have large influences on the microstructures of the InGaAsP epilayer, particularly on the modulation wavelength.
Published Version
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