Epitaxial Growth of Crystals on One-Degree Orientated Substrates

Abstract

DURING the oxidation of one-degree orientated metals, an unexpected variation in the dispositions of oxide crystallites was observed which appears to be similar to epitaxial growth¹ of crystals on single crystal substrate. In this process, the growing crystals (overgrowths) aligned themselves in a certain manner depending on the arrangement of atoms or ions of the substrate and more correctly on the potential energy configuration at or near the surface layers. Consequently a definite orientation relationship is established between their crystal axes, and the overgrowths are said to develop a two-degree orientation such that two axes of theirs are parallel to two of the substrate. This is more often expressed by a plane and axis of each. Single crystal substrates thus greatly influence the orientation of the overgrowths at least in the initial stage of their growth². On different faces of the substrate, the deposit orientation would normally be different, provided the growth condition is not too drastic or temperature not too high. The same orientation may, however, be induced on different faces of the substrate, but is again determined by the substrate structure. Numerous illustrations of such epitaxial growth of crystals are cited in the literature (see Pashley³).