To provide an electrode structure capable of simultaneously realizing high withstand power, low resistance, and cost reduction of a surface acoustic wave element.
An electrode 10 provided to the surface acoustic wave element is made into a two-layer structure in which the base film 12 of Ti and the upper layer film 13 of a composition (Al-Ti) made by adding Ti to Al as a main electrode material are successively laminated. A dissimilar metal element is added to Al as the main electrode material of the upper layer film 13, and is the same Ti as the constituent element of the base film 12. The concentration of Ti added to the upper layer film 13 is set to ≤0.4 wt.%. The film thickness of the upper layer film 13 and that of the base film are set so that the specific resistance value of the electrode becomes ≤10 μΩ cm. Mg or Cu with the concentration of ≤0.5 wt.% as a second dissimilar metal other than Ti is added to the upper layer film 13.
INOUE SHIYOUGO
UEDA MASANORI
FUJITSU LTD