Investigation of substrate rotation at glancing incidence on thin-film morphology

Abstract

Films deposited by evaporation at glancing angles form structures dependent on the speed of substrate rotation. If the substrate is held stationary, oblique columns are grown. For slow substrate rotation, helices are formed while faster rotation yields pillars. Silicon and silicon dioxide films grown under similar conditions were found to follow the typical morphological trend. In contrast, aluminum films formed by glancing angle deposition (GLAD) were found to be facetted structures which were peaked and isolated at high rotation speeds (dφ/dt>42 rpm), and flat for dφ/dt∼1.5 rpm. The results suggest that the primary limiting factor controlling GLAD microstructure growth may be a combination of both material temperature and crystal structure of the resulting film.