A study of the stress and resistivity of Al/Ti films deposited by an ion beam assisted process for surface acoustic wave devices applications

A highly textured Al/Ti films were deposited on 128° Y–X LiNbO3 substrates by ion beam assisted deposition. Influence of low energy Ar ion beam bombardment on the residual stress and resistivity of the Al/Ti films was investigated. It was found that the residual stress of the Al/Ti films varied from tensile to compressive with increases in ion energy or flux. The films fabricated at 0.5 keV and 3 μA/cm2 possessed zero residual stress. An increase in the compressive stress resulted in a decrease in resistivity. By controlling the ion incident energy and flux, we were able to control the film stress and resistivity that were related to the reliability of SAW devices.