Heterostructures of the form, InxGa1-xAs(5nm)/GaAs(5nm)/Si, were fabricated via metalorganic chemical vapor deposition and were annealed at 750C. A transmission electron microscopic study was made of the heterostructure, with particular attention being paid to interdiffusion between group-III elements. Plan-view transmission electron microscopy revealed that the epitaxial InxGa1-xAs /GaAs layer consisted basically of small island crystals. The morphology of the islands varied as a function of the In content. When x was greater than 0.1, the islands coalesced into larger ones; leaving small regions of so-called sea. The spacings of 022 moiré fringes varied spatially as a result of variations in In content in the epilayers. Cross-sectional transmission electron microscopic observations showed that there was no sharp heteroboundary between the InxGa1-xAs layer and the GaAs layer. The contrast of the 002 dark-field image was sensitive to the In content and revealed interdiffusion between In and Ga.

K.Kamei, K.Fujita, Y.Shiba, H.Katahama, Y.Maehara: Defect and Diffusion Forum, 1993, 95-98, 977-82