Biaxially textured Mo films with diverse morphologies by substrate-flipping rotation

A class of nanostructured Mo thin films was grown by DC magnetron sputtering using a robust substrate rotation mode called 'flipping rotation'. In this rotation mode, the substrate is arranged to rotate continuously at a fixed speed around an axis lying within and parallel to the substrate. The incident flux is perpendicular to the rotational axis, and the incident flux angle changes continuously. Mo nanostructured films, grown under different rotation speeds with three orders of magnitude spread (ranging from 0.008 to 24 rotation min(-1)), different flipping directions (clockwise and counter-clockwise), and different ending deposition angles, were characterized using scanning electron microscopy (SEM) and reflection high energy electron diffraction (RHEED) surface-pole-figure techniques. Despite their very different morphologies, such as 'C'-shaped, 'S'-shaped, and vertically aligned nanorods, the same (110)[1 (1) over bar0] biaxial texture with an average out-of-plane dispersion of similar to 15 degrees was observed. In contrast, we showed that only a fiber-textured Mo film was obtained by using the conventional rotation mode where the oblique incident flux angle was fixed with the substrate rotating around the surface normal.