| Summary: | 碩士 === 國立中央大學 === 機械工程研究所 === 93 === In this study, an epitaxial Mg-Al spinel layer was successfully grown on a
sapphire single crystal surface using solid-state reactions. The processes of
solid-state reactions with PVD and heat treatment were applied to grow
epitaxial layer with preferred orientation. And the layer composition and
structure can be confirmed by the further analyses. Through the controlling of
the heat treatment parameters, the variation of compositions and properties
influenced by different conditions on surface layer had been discussed.
From the experiment results, reaction layer showed different reaction rate
with various heat treatment, and it was proportion to the temperature and
duration. In additional, the orientation of epitaxial Mg-Al spinel layer would
depend on the cut of sapphire substrate. The hhh-type orientated spinel layer
preferred to grow on C- and A-plane sapphire, and the hh0-type orientated
spinel layer preferred to grow on M-plane sapphire. Simultaneously, the
in-plane orientation relationship between spinel epitaxial layer and sapphire
substrate could be obtained by φ scan. The morphology of the epitaxial spinel
layer surface will present a particular three-fold symmetrical structure by scanning
electron microscope. The model of atomic arrangement was employed to explain
the relationship between the surface morphology of spinel and its miller index.
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