Patent ID: 7268647

Claim:
A film bulk acoustic-wave resonator comprising: a substrate having a cavity, the substrate being formed of one of semi-insulating material and high-resistivity material; a bottom electrode partially fixed to the substrate, part of the bottom electrode is mechanically suspended above the cavity; a piezoelectric layer disposed on the bottom electrode, the shape of the piezoelectric layer is defined by a contour; a top electrode on the piezoelectric layer; a semiconductor intermediate electrode buried at and in a surface of the substrate, being located at the contour of the piezoelectric layer, the semiconductor region having a lower resistivity than the substrate, the intermediate electrode is connected to the bottom electrode in the inside of the contour; and a bottom electrode wiring connected to the semiconductor intermediate electrode extending from the contour to an outside of the contour in the plan view, wherein a longitudinal vibration mode along a thickness direction of the piezoelectric layer is utilized.