Origin of In-Plane Texturing in Sputtered Mo Films

Abstract

AbstractSputtered Mo films with a thickness of 2μm or greater have been previously shown by xray and TEM studies to grow with strong in-plane and out-of-plane textures under dynamic deposition conditions. In this work, the geometric conditions and mechanisms causing preferential grain alignment in the plane of growth for sputtered Mo films, with a nominal thickness of 2μm, were explored. Four different deposition configurations, obtained by varying the parameters such as the deposition angle and the rotation speed of the substrates, were used in order to modify the texture as studied by x-ray and SEM techniques. While a [110] type out-of-plane texture was observed for all four deposition configurations, a (110) type in-plane texture, and the corresponding grain alignment in the plane of growth, was observed only when the flux of adatoms was hitting the substrates at an oblique angle. The texture characteristics and the microstructure of the Mo films, as analyzed using the pole figure x-ray and SEM techniques, were observed to be very similar for films deposited on three different substrates, namely the Si(100) and Ni3Al(321) single crystals, and laboratory grade glass slides. The in-plane texture development under oblique deposition conditions was proposed to be due to a combination of two mechanisms, namely the preferential resputtering of some of the grains normal to and in the plane of growth caused by the higher energy adatoms in the flux, followed by termination of the preferentially sputtered grains due to geometric shadowing.