Elastic wave device and method for manufacturing the same
AssigneeMurata Manufacturing Co., Ltd.
InventorsMunehisa Watanabe, Hideki Iwamoto, Hajime Kando, Syunsuke Kido
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Abstract
An elastic wave device includes a supporting substrate, a high-acoustic-velocity film stacked on the supporting substrate and in which an acoustic velocity of a bulk wave propagating therein is higher than an acoustic velocity of an elastic wave propagating in a piezoelectric film, a low-acoustic-velocity film stacked on the high-acoustic-velocity film and in which an acoustic velocity of a bulk wave propagating therein is lower than an acoustic velocity of a bulk wave propagating in the piezoelectric film, the piezoelectric film is stacked on the low-acoustic-velocity film, and an IDT electrode stacked on a surface of the piezoelectric film.
Claims15
An elastic wave device comprising:
- a supporting substrate;
- a first film stacked on the supporting substrate;
- a piezoelectric film stacked on the first film;
- and
- an IDT electrode disposed on a surface of the piezoelectric film;
- wherein
- the supporting substrate includes at least one of silicon, sapphire, silicon carbide, and quartz;
- the first film includes at least one of silicon oxide, silicon oxynitride, tantalum oxide, media mainly composed of these materials, and media mainly composed of mixtures of these materials;
- the at least one of silicon oxide, silicon oxynitride, tantalum oxide, media mainly composed of these materials, and media mainly composed of mixtures of these materials of the first film is in direct contact with the supporting substrate;
- the piezoelectric film includes lithium tantalate or lithium niobate;
- a thickness of the piezoelectric film is about 1.5λ or less, and a thickness of the first film is about 2λ or less, where A is a wavelength of an elastic wave determined by an electrode period of the IDT electrode;
- and
- a surface acoustic wave propagates in the piezoelectric film.
An elastic wave device comprising:
- a high-acoustic-velocity supporting substrate;
- a first film stacked on the high-acoustic-velocity supporting substrate;
- a piezoelectric film stacked on the first film;
- and
- an IDT electrode disposed on a surface of the piezoelectric film;
- wherein
- the first film includes at least one of silicon oxide, silicon oxynitride, tantalum oxide, media mainly composed of these materials, and media mainly composed of mixtures of these materials;
- the at least one of silicon oxide, silicon oxynitride, tantalum oxide, media mainly composed of these materials, and media mainly composed of mixtures of these materials of the first film is in direct contact with the high-acoustic-velocity supporting substrate;
- the piezoelectric film includes lithium tantalate or lithium niobate;
- an acoustic velocity of a bulk wave propagating in the high-acoustic-velocity supporting substrate is higher than an acoustic velocity of a surface acoustic wave propagating in the piezoelectric film;
- and
- a thickness of the piezoelectric film is about 1.5λ or less, and a thickness of the first film is about 2λ or less, where λ is a wavelength of an elastic wave determined by an electrode period of the IDT electrode.
An elastic wave device comprising:
- a supporting substrate;
- a second film disposed on the supporting substrate;
- a first film stacked on the second film;
- a piezoelectric film stacked on the first film;
- and
- an IDT electrode disposed on a surface of the piezoelectric film;
- wherein
- the second film includes at least one of silicon, sapphire, silicon carbide, quartz, media mainly composed of these materials, and media mainly composed of mixtures of these materials;
- the first film includes at least one of silicon oxide, silicon oxynitride, tantalum oxide, media mainly composed of these materials, and media mainly composed of mixtures of these materials;
- the piezoelectric film includes lithium tantalate or lithium niobate;
- and
- a thickness of the piezoelectric film is about 1.5λ or less, and a thickness of the first film is about 2λ or less, where A is a wavelength of an elastic wave determined by an electrode period of the IDT electrode.
Dependencies are inferred from the claim text.