Dependence of stress in thin Al films on deposition and post-deposition temperature conditions

Here we present our study of the stress dependence in Al thin films on deposition conditions. We consider two types of Al 100-nm thick films: E-beam evaporated films and films obtained by magnetron sputtering. We investigate the Al film stress hysteresis in the environment with slowly increasing and decreasing temperature, i.e. during the gradual annealing. We consider the effect of deposition temperature on the film stress and grain size. We conclude that the annealing of Al films results in increased tensile stress component and decreasing of the compressive stress. Additionally, we observe that higher deposition temperature gives higher tensile stress and greater Al grain size in the film. In order to recover the film quality and reduce the grain size, one can increase the pressure of the buffering gas during the deposition.