Sputtered Al-Ti electrodes for high power durable SAW devices

DC magnetron sputtering and Ti addition for Al electrodes are studied to achieve higher durability of SAW (surface acoustic wave) devices operating at high frequency and high power. Experiments on SAW resonators and ladder-type SAW filters were conducted. The sputtering is shown to be better than conventional electron-gun evaporation for both the reproducibility of the film composition and durability. The sputtered Al films with 0.4-wt.%-to-0.8-wt.% Ti addition lead to a durability for three-times-larger power than for 0.7-wt.% Cu addition to evaporated Al films