Measurement of Piezoelectric Constant of ZnO Thin Film on Si Microstructure

The piezoelectric constant of a zinc oxide thin film on a silicon fixed beam was evaluated by a new method using a metal bar (Davies' bar) and a laser interferometer. The beam was fabricated by silicon micromachining techniques, and the ZnO film was deposited on it by rf sputtering. The film attached to the end of the Davies' bar was accelerated by striking the other end of the bar with a projectile, and the piezoelectric constant of the film was calculated from the strain and the electric charge. A reasonable value of e 31=0.43 C/m2 was obtained for the test specimen.