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[摘要]：Metamorphic pseudosubstrates of In0.15Ga0.85Sb are grown on p- and n-type GaSb substrates using InxGa1-xSb buffer layers compositionally graded in steps of x = 0.03. Extensive material characterization was done on the metamorphic layers to determine the in-plane lattice constant, density of threading and misfit dislocations, and surface roughness by high-resolution X-ray diffraction, cross-sectional and plan-view transmission electron microscopy, and atomic force microscopy. This is followed by a regrowth of p-i-n and n-i-p device layers of InxGa1-xSb (x = 0.10), lattice matched with the underlying partially relaxed metamorphic layer. Hole (beta) and previously unreported electron (alpha) ionization coefficients, at room temperature and 90 degrees C, respectively, were extracted from these structures. The results show that alpha > beta for In0.10Ga0.90Sb. A semianalytic expression was used to extract the temperature-dependent parameters for further investigations on practical avalanche photodiodes. |
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