Murata Manufacturing Co., Ltd.

Hideaki Takahashi

Tsutomu Takai

Taku Kikuchi

Koji Yamamoto

Shin Saijo

Naohiro Nodake

Hisashi Yamazaki

Yasuharu Nakai

Hirokazu Sakaguchi

An elastic wave device includes a piezoelectric substrate, an IDT electrode on the piezoelectric substrate, and a silicon oxide film arranged on the piezoelectric substrate to cover the IDT electrode. The IDT electrode includes first and second electrode layers laminated on each other, the first electrode layer is made of metal or an alloy with a density higher than a density of metal of the second electrode layer and a density of silicon oxide of the silicon oxide film, the piezoelectric substrate is made of LiNbOand &#x3b8; is in a range of equal to or greater than about 8&#xb0; and equal to or less than about 32&#xb0; with Euler Angles (0&#xb0;&#xb1;5&#xb0;, &#x3b8;, 0&#xb0;&#xb1;10&#xb0;) of the piezoelectric substrate, and the silicon oxide film contains hydrogen atoms, hydroxyl groups, or silanol groups.

Elastic wave device, high-frequency front end circuit, and communication apparatus

An acoustic wave device includes a high-acoustic-velocity film, a low-acoustic-velocity film provided on the high-acoustic-velocity film, a piezoelectric layer provided on the low-acoustic-velocity film, and an IDT electrode provided on the piezoelectric layer. An acoustic velocity of bulk waves propagating through the high-acoustic-velocity film is higher than an acoustic velocity of acoustic waves propagating through the piezoelectric layer. An acoustic velocity of bulk waves propagating through the low-acoustic-velocity film is lower than an acoustic velocity of bulk waves propagating through the piezoelectric layer. The low-acoustic-velocity film includes a material including hydrogen atoms.

Acoustic wave device, radio-frequency front-end circuit, and communication apparatus

An acoustic wave device includes a high-acoustic-velocity film, a piezoelectric layer provided directly or indirectly on the high-acoustic-velocity film, an IDT electrode provided on the piezoelectric layer, and a dielectric film provided on the piezoelectric layer to cover the IDT electrode. An acoustic velocity of bulk waves propagating through the high-acoustic-velocity film is higher than an acoustic velocity of acoustic waves propagating through the piezoelectric layer. The dielectric film includes a material including hydrogen atoms.

A method for manufacturing an acoustic wave device with an excellent frequency-temperature profile is performed such that the acoustic wave device produced includes a piezoelectric substrate, an IDT electrode located on the piezoelectric substrate, and a dielectric film mainly including Si and O and arranged on the piezoelectric substrate to cover the IDT electrode. The dielectric film is formed by sputtering in a sputtering gas containing HO.

Method for manufacturing acoustic wave device

A manufacturing method for a boundary acoustic wave device is provided which includes, an IDT electrode, a first dielectric layer, and a second dielectric layer on a piezoelectric substrate. The first dielectric layer is made of a deposited film. A thickness of the IDT electrode is about 10% or more of &#x3bb;. A difference between a height of the first dielectric layer, measured from an upper surface of the piezoelectric substrate, above a center of an electrode finger of the IDT electrode and a height of the first dielectric layer, measured from the upper surface of the piezoelectric substrate, above a center of a gap between adjacent electrode fingers, i.e., a magnitude of unevenness in an upper surface of the first dielectric layer, is about 5% or less of &#x3bb;.

Method of manufacturing a boundary acoustic wave device

A surface acoustic wave element has a small energy loss and when it is used in a filter device, suppresses a spurious component occurring near the resonant frequency of a principal response and improves the frequency characteristic near the pass band of the filter device. The surface acoustic wave element includes a piezoelectric substrate, a comb-shaped electrode, and an insulating film. The comb-shaped electrode is disposed on the piezoelectric substrate. The insulating film is disposed so as to cover the piezoelectric substrate and the comb-shaped electrode. Where &#x3bb; is the wavelength of an elastic wave that propagates in the piezoelectric substrate and h is the difference between the maximum and minimum values of a thickness dimension from the top surface of the piezoelectric substrate to the top surface of the insulating film, 0.01&#x2266;h/&#x3bb;&#x2266;0.03 is satisfied.

Surface acoustic wave element

In the boundary acoustic wave device, an IDT electrode, a first dielectric layer, and a second dielectric layer are provided on a piezoelectric substrate. The first dielectric layer is made of a deposited film. A thickness of the IDT electrode is about 10% or more of &#x3bb;. A difference between a height of the first dielectric layer, measured from an upper surface of the piezoelectric substrate, above a center of an electrode finger of the IDT electrode and a height of the first dielectric layer, measured from the upper surface of the piezoelectric substrate, above a center of a gap between adjacent electrode fingers, i.e., a magnitude of unevenness in an upper surface of the first dielectric layer, is about 5% or less of &#x3bb;.

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Nagaokakyo, Japan

Hideaki Takahashi