Substrate surface step effects on microstructure of epitaxial films

Autor:	Jinghua Guo, D. J. Lam, H. L. M. Chang
Rok vydání:	1992
Předmět:	Tetragonal crystal system Crystallography Materials science Physics and Astronomy (miscellaneous) Sapphire Mineralogy Chemical vapor deposition Substrate (electronics) Thin film Epitaxy Monoclinic crystal system Molecular beam epitaxy
Zdroj:	Applied Physics Letters. 61:3116-3117
ISSN:	1077-3118 0003-6951
DOI:	10.1063/1.107978
Popis:	Sapphire (0001) basal plane is a commonly used substrate for film depositions. Due to the threefold rotational symmetry of the (0001) substrate surface, epitaxial films deposited are expected to form at most three variants with relative orientations of 120° and 240°. However, epitaxial TiO2 (tetragonal) and VO2 (monoclinic) films deposited on sapphire (0001) substrates by the metalorganic chemical vapor deposition technique were found to have six variants of relative orientations of 60°, 120°, 180°, 240°, and 300° based on the x‐ray diffraction studies. Furthermore, epitaxial MgO (cubic) films deposited on sapphire (0001) substrates by the molecular beam epitaxy technique were found to have two variants which are mirror images about the (1210) plane from the high resolution electron microscopy. We show that these unconventional film microstructures found experimentally are caused by the substrate surface steps.
Databáze:	OpenAIRE
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