Correlation between texture and mechanical stress durability of thin aluminum films

Abstract

In this article, differently textured aluminum (Al) metallizations of surface acoustic wave (SAW) devices have been exposed to cyclic mechanical stress in order to investigate a potential correlation between their texture and their mechanical stress durability. Samples of SAW devices with differently textured Al thin film electrodes have been manufactured, and texture measurements have been carried out on all samples with electron backscatter diffraction. Subsequently, the SAW devices have been operated at heavy electrical load until a defined mechanical fatigue of its Al electrodes occurred. SAW devices with highly textured Al electrodes showed almost 20 times higher power durability than SAW devices with untextured Al electrodes. We show that this increase in electrical power durability has to be fully attributed to the strongly enhanced mechanical stress durability of highly textured Al films. Furthermore, a positive correlation between the Al films' texture and its electrical conductivity has been found.