The Role of Roughness in Texture Development

Abstract

To examine the dependence of in-plane texture development on substrate surface morphology, deposition was performed on an intentionally roughened surface. 2 μm thick sputter deposited Mo films were macroscopically roughened by ion bombardment. This process created aligned mounds on the surface which were ˜1 μm in length, ˜0.1 μm in width and ˜0.04 miimn height. To remove crystallographic orientation effects, this surface was coated with a thin layer of graphite. Using these roughened, coated surfaces as a new substrates, the role of well defined macroscopic roughness in subsequent thin film growth was probed. Mo films were deposited onto these prepared substrates which were placed on a rotating platen under a stationary ion sputter source. When the mounds are aligned with their elongated axes normal to the rotation direction, little to no in-plane texture is found. The same deposition on a flat surface, or on the roughened surface with the mounds oriented parallel to the platen rotation direction, gives films with a high degree of in-plane texture. Scanning electron microscopy, transmission electron microscopy, and transmission electron diffraction data will be presented to corroborate these findings.