Incident flux angle induced crystal texture transformation in nanostructured molybdenum films

Abstract

Molybdenum films were observed to undergo a dramatic change in crystal texture orientation when the incident flux angle was varied in an oblique angle sputter deposition on amorphous substrates. Reflection high-energy electron diffraction pole figure and scanning electron microscopy were used to analyze in detail the texture orientation of the films. The normal incident deposition resulted in a fiber texture film with the minimum energy (110) crystal plane parallel to the substrate surface. A (110)[11¯0] biaxial texture was observed for the samples grown with low incident angles of less than 45°, with respect to the surface normal. On the other hand, for an oblique angle deposition of larger than 60°, a (111)[112¯] biaxial texture was observed and appeared to be consistent with a zone T structure where the geometrically fastest growth [001] direction of a crystal plays a dominant role in defining the texture. We argue that a structural transition had occurred when the incident flux was varied from near normal incidence to a large angle.