Surface acoustic wave device.

摘要

A surface acoustic wave device having a single-crystal aluminum nitride film wherein when the direction of propagation of the surface acoustic wave is expressed by ( lambda , mu , theta ) according to the Euler angle notation, theta is set to 90 degrees, lambda to a desired angle, and mu to an angle in the range of 30 to 150 degrees. In a surface acoustic wave device having a c-axis-oriented aluminum nitride film, the direction of c-axis orientation of the piezoelectric film is inclined within a plane containing the direction of propagation of the surface acoustic wave and perpendicular to the surface of the piezoelectric film at an angle in the range of about +/-30 degrees to about +/-150 degrees with respect to a normal to the piezoelectric film. The devices are 1.122% in maximum coupling coefficient.