Patent ID: 7482737
Filing Date: 2009-01-27
Classification: H01L,H03H

Abstract:
1. A piezoelectric thin film resonator comprising: a substrate; and a piezoelectric layered structure including a lower electrode, piezoelectric thin film and upper electrode formed on the substrate in this order so that a vibration space is formed below the piezoelectric layered structure, and a vibration portion including a part of the piezoelectric layered structure corresponding to the vibration space is formed; wherein the lower electrode has a layered film constituted by a first layer containing one of a layer containing: molybdenum as a major component and a layer containing tungsten as a major component and having a thickness d wherein the layer containing ruthenium as a major component has a full-width half maximum (FWHM) of a rocking curve of a (0002) diffraction peak of ruthenium of 3.0° or less, the layer containing molybdenum as a major component has a full-width half maximum (FWHM) of a rocking curve of a (110) diffraction peak of molybdenum of 3.0° or less, and the layer containing tungsten as a major component has a full-width half maximum (FWHM) of a rocking curve of a (110) diffraction peak of tungsten of 3.0° or less, and wherein the piezoelectric thin film is an aluminum nitride thin film having a full-width half maximum (FWHM) of a rocking curve of a (0002) diffraction peak of 2.0° or less.