PIEZOELECTRIC DEVICE, AND METHOD FOR MANUFACTURING PIEZOELECTRIC DEVICE

摘要

Provided are a piezoelectric device that prevents oxidation of an extremely thin piezoelectric thin film and thereby prevents damage to electrodes formed on the piezoelectric thin film by pyroelectric charge and a method for manufacturing such a piezoelectric device. A silicon oxide film (90) is deposited on a surface (12) of a single-crystal piezoelectric substrate (1) closer to an ion-implanted region (100) by sputtering, and a silicon nitride film (91) is deposited on a surface of the dielectric film (90) opposite the side thereof closer to the single-crystal piezoelectric substrate (1) by sputtering. The silicon oxide film (90) has a composition that is deficient in oxygen relative to the stoichiometric composition. Accordingly, little oxygen is supplied from the silicon oxide film (90) to the piezoelectric thin film (10) during heat treatment of a piezoelectric device (101). This prevents oxidation of the piezoelectric thin film (10) and therefore formation of an oxide layer with high resistivity in the piezoelectric thin film (10). As a result, a pyroelectric charge generated in the piezoelectric thin film (10) can flow to the silicon oxide film (90).