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.

Various methods and systems are provided for a transducer for a deployable catheter. In one example, a method for forming the transducer includes coupling an acoustic stack to a shape memory material while in a planar configuration to form a transducer and exposing the shape memory material to a curling stimulus to adjust the transducer to a curved configuration.

A nasal-plug filter device including a device body, a filter, a first actuator, a second actuator, and a gas sensor is provided. The device body has a ventilating channel, and the ventilating channel has an inlet end and an outlet end. The filter is disposed at the outlet end. The first actuator is disposed at the inlet end for being driven to transmit gas outside the device body into the device body. The second actuator is stacked on and bonded to the first actuator, and the second actuator is driven to transmit the gas transmitted by the first actuator to the filter to be filtered and purified. The gas sensor is disposed at the outlet end for detecting a gas quality of the gas at the outlet end. A connection element may be provided for connecting two nasal-plug filter devices with each other.

The disclosed technology features methods for the manufacture of electrical components such as ultrasound transducers. In particular, the disclosed technology provides methods of patterning electrodes, e.g. in the connection of an ultrasound transducer to an electrical circuit; methods of depositing metal on surfaces; and methods of making integrated matching layers for an ultrasound transducer. The disclosed technology also features ultrasound transducers produced by the methods described herein.

Provided is a piezoelectric film including an AlN crystal, and a first element and a second element doped to the AlN crystal. The first element is an element having an ionic radius larger than an ionic radius of Al. The second element is an element having an ionic radius smaller than the ionic radius of Al. Also provided are piezoelectric film laminated body including an underlayer and a piezoelectric film including ScAlN, and a method of manufacturing the same. The underlayer has a crystal lattice having six-fold symmetry or three-fold symmetry. Also provided are a piezoelectric film including ScAlN having a laminated structure of a hexagonal crystal and a cubic crystal, and a method of manufacturing the same. The cubic crystal is doped with an element other than trivalent element.

Provided is a piezoelectric film including an AlN crystal, and a first element and a second element doped to the AlN crystal. The first element is an element having an ionic radius larger than an ionic radius of Al. The second element is an element having an ionic radius smaller than the ionic radius of Al. Also provided are piezoelectric film laminated body including an underlayer and a piezoelectric film including ScAlN, and a method of manufacturing the same. The underlayer has a crystal lattice having six-fold symmetry or three-fold symmetry. Also provided are a piezoelectric film including ScAlN having a laminated structure of a hexagonal crystal and a cubic crystal, and a method of manufacturing the same. The cubic crystal is doped with an element other than trivalent element.

In a piezoelectric device, a piezoelectric driving portion includes layers and is directly or indirectly supported by a base portion. The piezoelectric driving portion includes a piezoelectric layer, an upper electrode layer, and a lower electrode layer. The upper electrode layer is disposed on the upper side of the piezoelectric layer. The lower electrode layer faces at least a portion of the upper electrode layer with the piezoelectric layer interposed therebetween. The piezoelectric driving portion includes a through groove extending through the piezoelectric driving portion in the vertical direction, so that a pair of inner side surfaces are provided. The pair of inner side surfaces each include a first small-width portion in which the width of the through groove decreases in a downward direction from an upper end surface of the piezoelectric layer.

A bonded body includes a supporting substrate; a piezoelectric material substrate composed of a material selected from the group consisting of lithium niobate, lithium tantalate and lithium niobate-lithium tantalate; and a bonding layer bonding the supporting substrate and the piezoelectric material substrate and contacting a main surface of the piezoelectric material substrate. It is provided that at least one of a bonding surface of the supporting substrate and a bonding surface of the piezoelectric material substrate is measured by X-ray reflectivity method and that 1 is assigned to a signal intensity in the case of total reflection. A relative intensity I of a reflected light from the bonding surface is approximated by the following formula (1) in a range of 1.0×10.sup.−4 or larger and 1.0×10.sup.−1 or smaller.
I=a(2θ).sup.−b  (1)
(θ represents an incident angle of an X-ray with respect to the bonding surface, a is 1.0×10.sup.−5 or larger and 2.0×10.sup.−3 or smaller, and b is 5.0 or larger and 9.0 or smaller.)

A bonded body includes a supporting substrate; a piezoelectric material substrate composed of a material selected from the group consisting of lithium niobate, lithium tantalate and lithium niobate-lithium tantalate; and a bonding layer bonding the supporting substrate and the piezoelectric material substrate and contacting a main surface of the piezoelectric material substrate. It is provided that at least one of a bonding surface of the supporting substrate and a bonding surface of the piezoelectric material substrate is measured by X-ray reflectivity method and that 1 is assigned to a signal intensity in the case of total reflection. A relative intensity I of a reflected light from the bonding surface is approximated by the following formula (1) in a range of 1.0×10.sup.−4 or larger and 1.0×10.sup.−1 or smaller.
I=a(2θ).sup.−b  (1)
(θ represents an incident angle of an X-ray with respect to the bonding surface, a is 1.0×10.sup.−5 or larger and 2.0×10.sup.−3 or smaller, and b is 5.0 or larger and 9.0 or smaller.)

A piezoelectric-body film joint substrate includes a substrate, a substrate electrode provided on the substrate, a first piezoelectric-body film stuck on the substrate electrode and including a first piezoelectric film and a first upper electrode film formed on the first piezoelectric film, and a second piezoelectric-body film stuck on the first upper electrode film and including a second piezoelectric film different from the first piezoelectric film and a second upper electrode film formed on the second piezoelectric film.