| 摘要 |
PURPOSE:To obtain characteristics with a wide specific band by providing thin film members on both surfaces of a piezoelectric thin film with electrodes between, and thus forming a piezoelectric oscillator. CONSTITUTION:On a substrate 31 having an opening made by etching, a thin film 33 of SiO2 is provided and on this thin film 33, an electrode 36 is formed. On the electrode 36, a piezoelectric thin film 35 is formed and on the thin film 35, an electrode 37 and a thin film 34 of SiO2 are formed. In this case, when the total thickness of the thin films 33 and 34 is a half as great as the (t) thickness of the piezoelectric thin film 35, the electromechanical coupling coefficient of multiple-frequency oscillation of degree of an even number decreases abruptly in accordance with an increase in the thickness of the thin film 34. When the thin films 33 and 34 have the same characteristics, the electromechanical coupling coefficient of basis oscillation is maximized with the thin films 33 and 34 equal in thickness. |
