Patent ID: 8726475
Filing Date: 2014-05-20
Classification: H03H,Y10T

Abstract:
1. A method for producing a piezoelectric thin-film resonator comprising the steps of: forming on a substrate a sacrificial layer having a top principal surface and end surface portions; performing a plasma treatment on the sacrificial layer so as to planarize the sacrificial layer and reduce a surface roughness of the end surface portions and the top principal surface of the sacrificial layer to 5 nm or less; forming a strip-shaped dielectric film so as to be continuously disposed on a surface of the substrate, the end surface portions, and the top principal surface of the sacrificial layer; forming a lower electrode on the dielectric film; forming a piezoelectric thin-film on the dielectric film on which the lower electrode has been formed; forming an upper electrode on the piezoelectric thin-film such that a portion of the upper electrode and a portion of the lower electrode face each other on an upper surface of the sacrificial layer with the piezoelectric thin-film disposed therebetween; and removing the sacrificial layer to form an air-gap between the substrate and the dielectric film.