Shin-etsu Chemical Co., Ltd.

Nippon Hoso' Kyokai

Other

Masayuki Tanno

Toshihiko Ryuo

Shoji Akiyama

Toshiaki Watanabe

Satoru Fukuda

Yoshiyuki Shiono

Koji Kato

Yoshinori Kuwabara

Masanori Ikari

Jun Abe

Shozo Shirai

Toshihiro Nomoto

Takao Kuki

Jun Horikoshi

Shohei Kozakai

Kazutoshi Nagata

Junichi Kushibiki

Tatsuo Mori

A piezoelectric composite substrate for SAW devices with small loss is provided. A composite substrate for a surface acoustic wave device according to one embodiment of the present invention has a piezoelectric single crystal thin film, a support substrate, and a first intervening layer between the piezoelectric single crystal thin film and the support substrate. In said composite substrate, the first intervening layer is in contact with the piezoelectric single crystal thin film, and the acoustic velocity of the transverse wave in the first intervening layer is faster than the acoustic velocity of the fast transverse wave in the piezoelectric single crystal thin film.

Composite substrate for surface acoustic wave device and manufacturing method thereof

A method of manufacturing a composite substrate that includes bonding a silicon (Si) wafer having an interstitial oxygen concentration of 2 to 10 ppma to a piezoelectric material substrate as a support substrate, and thinning the piezoelectric material substrate after the bonding. The piezoelectric material substrate is particularly preferably a lithium tantalate wafer (LT) substrate or a lithium niobate (LN) substrate.

Method of manufacturing composite substrate

There are provided a method for manufacturing a substrate excellent in heat dissipation with a small loss in radio frequencies with no need of a high temperature process in which a metal impurity is diffused, and a substrate of high thermal conductivity. A composite substrate according to the present invention is a composite substrate having a piezoelectric single crystal substrate, a support substrate, and an intermediate layer provided between the piezoelectric single crystal substrate and the support substrate. The intermediate layer is a film formed of an inorganic material, and at least a part of the film is thermally synthesized silica. The intermediate layer may be separated into at least two layers along the bonding surface of the composite substrate. The first intermediate layer in contact with the support substrate may be a layer including thermally synthesized silica.

Composite substrate, surface acoustic wave device, and method for manufacturing composite substrate

Provided is a composite substrate for surface acoustic wave device which does not cause peeling of an entire surface of a piezoelectric single crystal film even when heating the film to 400&#xb0; C. or higher in a step after bonding. The composite substrate is formed by providing a piezoelectric single crystal substrate and a support substrate, forming a film made of an inorganic material on at least one of the piezoelectric single crystal substrate and the support substrate, and joining the piezoelectric single crystal substrate with the support substrate so as to sandwich the film made of the inorganic material.

Method of producing composite substrate for surface acoustic wave device

A composite substrate includes a single crystal support substrate containing first element as a main component; an oxide single crystal layer provided on the single crystal support substrate and containing a second element (excluding oxygen) as a main component; and an amorphous layer provided in between the single crystal support substrate and the oxide single crystal layer and containing a first element, a second element, and Ar, the amorphous layer having a first amorphous region in which proportion of the first element is higher than proportion of the second element, and a second amorphous region in which the proportion of the second element is higher than the proportion of the first element, concentration of Ar contained in the first amorphous region being higher than concentration of Ar contained in the second amorphous region and being 3 atom % or more.

Composite substrate and method of manufacturing composite substrate

To provide a method for producing a composite wafer capable of reducing a spurious arising by reflection of an incident signal on a joint interface between a lithium tantalate film and a supporting substrate, in the composite wafer including a supporting substrate having a low coefficient of thermal expansion, and a lithium tantalate film having a high coefficient of thermal expansion stacked on the supporting substrate. The method for producing a composite wafer is a method for producing a composite wafer that produces a composite wafer by bonding a lithium tantalate wafer having a high coefficient of thermal expansion to a supporting wafer having a low coefficient of thermal expansion, wherein prior to bonding together, ions are implanted from a bonding surface of the lithium tantalate wafer and/or the supporting wafer, to disturb crystallinity near the respective bonding surfaces.

Method for producing composite wafer

An object of the present invention is to provide a bonded substrate which is excellent in temperature characteristics and suppresses unnecessary response due to reflection of an elastic wave at a bonding interface. [Means to Solve the Problems] The present invention is unique in that a bonded substrate is constructed by bonding a LiTaOsubstrate and a base plate wherein a Li concentration at a base plate-bonding face of the LiTaOsubstrate is higher than that at a LiTaOsubstrate-side end face of the bonded substrate, that the difference between the Li concentration at the base plate-bonding face of the LiTaOsubstrate and the Li concentration at the LiTaOsubstrate-side end face of the bonded substrate is 0.1 mol % or greater, that the Li concentration at the base plate-bonding face of the LiTaOsubstrate satisfies an equation Li/(Li+Ta)&#xd7;100=(50+&#x3b1;) mol %, where &#x3b1; is in the range of &#x2212;1.2&#x3c;&#x3b1;&#x3c;0.5, that the Li concentration at the LiTaOsubstrate-side end face of the bonded substrate satisfies an equation Li/(Li+Ta)&#xd7;100=(48.5+&#x3b2;) mol %, where &#x3b2; is in the range of &#x2212;0.5&#x3c;&#x3b2;&#x3c;0.5, and that the thickness measured from the base plate-bonding face of the LiTaOsubstrate to the LiTaOsubstrate-side end face of the finished bonded substrate becomes greater than 5 times but less than 20 times the wavelength of the surface acoustic wave or that of the leaky surface acoustic wave.

Bonded substrate and a manufacturing method thereof, and a surface acoustic wave device using the said bonded substrate

[Object] It is an object of the present invention to provide a lithium tantalate single crystal substrate which undergoes only small warpage, is free from cracks and scratches, has better temperature non-dependence characteristics and a larger electromechanical coupling coefficient than a conventional Y-cut LiTaOsubstrate. [Means to solve the Problems] The lithium tantalate single crystal substrate of the present invention is a rotated Y-cut LiTaOsingle crystal substrate having a crystal orientation of 36&#xb0; Y-49&#xb0; Y cut characterized in that: the substrate is diffused with Li from its surface into its depth such that it has a Li concentration profile showing a difference in the Li concentration between the substrate surface and the depth of the substrate; and the substrate is treated with single polarization treatment so that the Li concentration is substantially uniform from the substrate surface to a depth which is equivalent to 5-15 times the wavelength of either a surface acoustic wave or a leaky surface acoustic wave propagating in the LiTaOsubstrate surface.

Lithium tantalate single crystal substrate, bonded substrate, manufacturing method of the bonded substrate, and surface acoustic wave device using the bonded substrate

Provided is a high-performance composite substrate for surface acoustic wave device which has good temperature characteristics and in which spurious caused by the reflection of a wave on a joined interface between a piezoelectric crystal film and a support substrate is reduced. The composite substrate for surface acoustic wave device includes: a piezoelectric single crystal substrate; and a support substrate, where, at a portion of a joined interface between the piezoelectric single crystal substrate and the support substrate, at least one of the piezoelectric single crystal substrate and the support substrate has an uneven structure, a ratio of an average length RSm of elements in a cross-sectional curve of the uneven structure to a wavelength &#x3bb; of a surface acoustic wave when the substrate is used as a surface acoustic wave device is equal to or more than 0.2 and equal to or less than 7.0.

Composite substrate for surface acoustic wave device, method of producing composite substrate for surface acoustic wave device, and surface acoustic wave device using composite substrate

An object of the present invention is to provide a method of manufacturing a composite substrate including a piezoelectric layer with less Li amount variation and a support substrate. A method of manufacturing a composite substrate of the present invention includes a step of performing ion implantation into a piezoelectric substrate, a step of bonding the piezoelectric substrate and the support substrate, a step of separating the bonded substrate, at an ion-implanted portion of the piezoelectric substrate, into the piezoelectric layer bonded to the support substrate and the remaining piezoelectric substrate after the step of bonding the piezoelectric substrate and the support substrate, and a step of diffusing Li into the piezoelectric layer after the separating step.

A lithium tantalate single crystal substrate for a surface acoustic wave device that is a rotated Y-cut LiTaO3 substrate whose crystal orientation has a Y-cut angle of not smaller than 36&#xb0; and not larger than 49&#xb0; and which has such a Li concentration profile after diffusion of Li into the substrate from the surface thereof that the Li concentration at the surface of the substrate differs from that inside the substrate. A shear vertical type elastic wave whose main components are vibrations in the thickness direction and in the propagation direction and which is among those elastic waves which propagate in the X axis direction within the surface of this LiTaO3 substrate has an acoustic velocity of not lower than 3140 m/s and not higher than 3200 m/s.

Lithium tantalate single crystal substrate for a surface acoustic wave device and a device using the same, and a manufacturing method thereof and an inspection method thereof

[Object] An object of the present invention is to provide a method for manufacturing an oxide single crystal substrate having less dispersion in characteristics within the substrate surface. [Means to solve the Problems] In the manufacture method of the present invention, a powder containing a Li compound is dispersed in a medium to form a slurry, and heat is applied while the slurry is in contact with the surface of the oxide single crystal substrate, so as to diffuse Li into the substrate from the surface thereof to effect a modification of the substrate; or after the slurry is brought into contact with the surface of the oxide single crystal substrate, the oxide single crystal substrate is buried in a powder containing the Li compound, and heat is applied to effect the diffusion of Li in the substrate from the surface thereof whereby a modification of the substrate occurs.

Method of manufacturing an oxide single crystal substrate for a surface acoustic wave device

Garnet crystal for Faraday rotator and optical isolator having the same

Faraday rotator and magneto-optical element using the same

A magnetostatic wave device includes a Gd,Ga,O,substrate off-angled from a &lcub;110&rcub; plane. A magnetic thin film including a crystal of garnet is formed on the Gd,Ga,O,substrate by liquid-phase epitaxy. A transducer operates for exciting magnetostatic wave in the magnetic thin film in response to an RF electric signal. A bias magnetic field is applied to the magnetic thin film. There is a relation as 20&deg;&lE;&verbar;&thgr;,&plus;&thgr;,&verbar;&lE;35&deg;, where &ldquo;&thgr;,&rdquo; denotes an angle between a longitudinal direction of the transducer and a <001> orientation of the crystal in the magnetic thin film, and &ldquo;&thgr;,&rdquo; denotes an angle between a transverse direction of the transducer and a specified direction. The specified direction is parallel to a line of intersection between a horizontal plane of the magnetic thin film and a given plane which is perpendicular to the horizontal plane of the magnetic thin film and which contains a direction of the bias magnetic field. Also, there is a relation as &verbar;&thgr;,&verbar;&lE;75&deg;, where &ldquo;&thgr;,&rdquo; denotes an angle between the specified direction and the direction of the bias magnetic field.

Growing community of inventors

Annaka, Japan

Masayuki Tanno