Piezoelectric thin film resonator and frequency variable resonator using the resonator
AssigneeKabushiki Kaisha Toshiba
InventorsKazuhide Abe, Naoko Yanase, Takaaki Yasumoto, Ryoichi Ohara, Tatsuo Shimizu, Takashi Kawakubo
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Abstract
A piezoelectric thin film resonator which comprises a first electrode, a second electrode, and a piezoelectric film which is interposed between the first electrode and the second electrode, and formed of an epitaxial ferroelectric thin film containing barium titanate, a spontaneous polarization of the epitaxial ferroelectric thin film being uniaxially orientated in a direction normal to a film surface.
Claims26
A piezoelectric thin film resonator which comprises:
- a first electrode;
- a second electrode;
- and
- a piezoelectric film which is interposed between said first electrode and said second electrode, and formed of an epitaxial ferroelectric thin film comprising barium titanate, a spontaneous polarization of said epitaxial ferroelectric thin film being uniaxially orientated in a direction normal to a film surface.
A piezoelectric thin film resonator which comprises:
- a first electrode;
- a second electrode;
- and
- a piezoelectric film which is interposed between said first electrode and said second electrode, and formed of an epitaxial ferroelectric thin film comprising barium titanate, wherein a spontaneous polarization of said epitaxial ferroelectric thin film is uniaxially orientated in (001) azimuth and an in-plane two-dimensional lattice strain xm of said epitaxial ferroelectric thin film is confined to meet an expression of:
- xm>−0.025.
A piezoelectric thin film resonator which comprises:
- a first electrode;
- a second electrode;
- and
- a piezoelectric film which is interposed between said first electrode and said second electrode, and formed of an epitaxial ferroelectric thin film which has a perovskite-type crystal structure, a spontaneous polarization of said epitaxial ferroelectric thin film being uniaxially orientated in a direction normal to a film surface.
A piezoelectric thin film resonator which comprises:
- a first electrode;
- a second electrode;
- and
- a piezoelectric film which is interposed between said first electrode and said second electrode, and formed of an epitaxial ferroelectric thin film which has a perovskite-type crystal structure, wherein a spontaneous polarization of said epitaxial ferroelectric thin film is uniaxially orientated in (001) azimuth and an in-plane two-dimensional lattice strain xm of said epitaxial ferroelectric thin film is confined to meet an expression of:
- xm>−0.025.
Dependencies are inferred from the claim text.