Patent ID: 8854156
Filing Date: 2014-10-07
Classification: H03H

Abstract:
1. A thin-film piezoelectric resonator comprising: a substrate; a piezoelectric resonator stack formed on the substrate and having a piezoelectric layer and top and bottom electrodes formed so as to face each other through the piezoelectric layer; and a cavity or an acoustic reflection layer formed between the substrate and piezoelectric resonator stack, the piezoelectric resonator stack having a vibration region where the top and bottom electrodes overlap each other as viewed in the thickness direction of the piezoelectric resonator stack, the vibration region including a first vibration region, a second vibration region, and a third vibration region, as viewed in the thickness direction of the piezoelectric resonator stack, the first vibration region being located at the outermost side, the third vibration region being located at the innermost side and not contacting with the first vibration region, and the second vibration region being interposed between the first vibration region and third vibration region, the resonance frequency of the primary thickness longitudinal vibration of the vibration region being f the piezoelectric resonator stack having a support region located outside the vibration region as viewed in the thickness direction of the piezoelectric resonator stack and a buffer region located between the vibration region and support region as viewed in the same direction, and contacting the substrate in the support region, the bottom electrode having, in the support region, a support portion extending along the boundary between the support region and buffer region, and the width w