Stress evolution in sputtered vanadium-tungsten alloys

Abstract

While metal alloy films are used in many applications, there remains a rather limited series of studies of their stress evolution during growth as compared to elemental films. Here, we provide measurements of the sputter deposition stress evolution of VxW1-x alloys, which is a system that forms a body centered cubic solid solution across all its compositions. By increasing either the tungsten content or the growth rate, we note an increasing trend towards a compressive stress state. Since the crystallite size is approximately the same for all alloys and growth rates, we conclude that the increasing tungsten content enhances the effect of energetic particle deposition (atomic peening) on the stress facilitating this change. The results suggest that stress can be understood in terms of the same physical processes that have been proposed previously to explain stress in elemental films. These mechanisms, described in the text include effects of non-energetic growth kinetics, microstructural evolution and energetic particle bombardment.