Abstract: In a thin film device including a thin film electrode which has a main electrode layer formed of tungsten, a thin film electrode having a low resistivity is realized. There is provided a thin film device including a thin film electrode that has an underlayer and a main electrode layer formed on the underlayer. The underlayer is formed of a titanium-tungsten alloy having a crystalline structure with a wavy-like surface morphology, and the main electrode layer is formed of tungsten having a crystalline structure with a wavy-like surface morphology.

Abstract: A piezoelectric resonator that includes a single crystal Si layer, a piezoelectric thin film formed from aluminum nitride and provided on the single crystal Si layer, and first and second electrodes provided so as to sandwich the piezoelectric thin film. An element excluding nitrogen and aluminum is doped into the piezoelectric thin film formed from aluminum nitride, and a synthetic acoustic velocity of portions of the piezoelectric resonator other than the single crystal Si layer substantially coincide with the acoustic velocity of the single crystal Si layer.

Abstract: A variable capacitance device that operates properly at a point along a signal line through which a high-voltage RF signal passes while reducing a necessary DC voltage includes a substrate, a beam, and lower drive electrodes. The beam is connected to the substrate through a support portion. Lower drive electrodes and the beam generate a capacitance when a DC voltage is applied, and an electrostatic force due to this capacitance deforms the beam. The lower drive electrodes face the beam and are coupled to each other through the beam. An RF signal propagates between the lower drive electrodes.

Abstract: A vibrating device having a number 2N (N is an integer equal to 2 or larger) of tuning fork arms extending in a first direction are arranged side by side in a second direction. Phases of flexural vibrations of the number N of tuning fork arms positioned at a first side of an imaginary line A, which passes a center of a region in the second direction where the number 2N of tuning fork arms are disposed and which extends in the first direction, are symmetric to phases of flexural vibrations of the number N of tuning fork arms positioned at a second side of the imaginary line opposite the first side.

Abstract: A vibrating device having tuning fork arms extending in a first direction that are joined to a base portion and are arranged side by side in an second direction. Each of the tuning fork arms has a structure that a silicon oxide layer is laminated on a Si layer made of a degenerate semiconductor, and that an excitation portion is provided on the silicon oxide layer. When a total thickness of the Si layer is denoted by T1, a total thickness of the silicon oxide layer is denoted by T2, and the temperature coefficient of resonant frequency (TCF) when the silicon oxide layer is not provided on the Si layer is denoted by x, a thickness ratio T2/(T1+T2) is within a range of (?0.0002x2?0.0136x+0.0014)±0.05.

Abstract: A vibrating device that is in the form of a rectangular plate having opposed long sides and opposed short sides, and that utilizes an expanding and contracting vibration mode in a direction of the short sides. The vibrating device includes a Si layer made of a degenerate semiconductor, a silicon oxide layer, a piezoelectric layer, and first and second electrodes through which a voltage is applied to the piezoelectric layer. When a total thickness of the Si layer is denoted by T1, a total thickness of the silicon oxide layer is denoted by T2, and the TCF in the vibrating device when the silicon oxide layer 3 is not provided is denoted by x(ppm/K), T2/(T1+T2) is within a range of (?0.0003x2?0.0256x+0.0008)±0.05.

Abstract: A piezoelectric thin-film resonator includes a piezoelectric thin film which includes aluminum nitride containing Sc and which has a concentration distribution such that the concentration of Sc is non-uniform in a thickness direction of the piezoelectric thin film; a first electrode; a second electrode facing the first electrode across the piezoelectric thin film; and a substrate supporting a piezoelectric vibrating section defined by the piezoelectric thin film and the first and second electrodes.

Abstract: A duplexer includes a transmitting filter including serial resonators and parallel resonators connected in a ladder configuration, and a receiving filter. A resonator of the serial resonators and the parallel resonators in the transmitting filter that is arranged closest to a common terminal of the transmitting filter and the transmitting filter includes a surface acoustic wave resonator, and at least one resonator excluding the resonator that is arranged closest to the common terminal includes a film bulk acoustic wave resonator.

Abstract: A piezoelectric thin film comprising aluminum nitride containing magnesium and hafnium, wherein a content of the hafnium based on 100 atomic % of the magnesium is 8 atomic % or more and less than 100 atomic %, and a total content of the magnesium and hafnium based on a sum of a content of the magnesium, hafnium, and aluminum is in a range of 47 atomic % or less.

Abstract: A piezoelectric member that achieves a high sound speed includes a silicon-containing substrate and a piezoelectric layer. The piezoelectric layer is disposed on the silicon-containing substrate. At least a surface layer of the piezoelectric layer on a side opposite to the silicon-containing substrate is made of BxAl1-xN (0<x?0.2).

Abstract: A vibrating device having vibrating arms connected to a supporter. The vibrating arms have an n-type Si layer which is a degenerated semiconductor and an exciter provided on the n-type Si layer. The exciter has a piezoelectric thin film and a first and second electrodes with the piezoelectric thin film interposed therebetween.

Abstract: A piezoelectric device that includes: a diaphragm; a supporting part configured to support at least a portion of an end of the diaphragm; a piezoelectric film disposed along a portion supported by the supporting part on the diaphragm, a width of the film along the supported portion being narrower than a width of the portion; a lower electrode disposed at a face of the piezoelectric film on a diaphragm side; and an upper electrode disposed on a face of the piezoelectric film on an opposite side to the diaphragm.

Abstract: A bulk wave resonator that includes an aluminum nitride film containing scandium on a substrate, a first electrode disposed on one surface of the aluminum nitride film containing scandium, and a second electrode disposed on the other surface of the aluminum nitride film containing scandium. The aluminum nitride film containing scandium includes a portion acoustically isolated from a top surface of the substrate. The first electrode overlaps the second electrode with the aluminum nitride film containing scandium interposed therebetween. The overlap forms a piezoelectric vibrating portion. The scandium content of the aluminum nitride film containing scandium is 5 atomic percent or more and 43 atomic percent or less when Sc and Al of the aluminum nitride film containing scandium constitute 100 atomic percent.

Abstract: A surface acoustic wave device includes a high acoustic velocity film in which a transversal wave propagates at a higher acoustic velocity than in a ScAlN film laminated on a substrate made of silicon or glass. The ScAlN film is laminated on the high acoustic velocity film, and IDT electrodes are laminated on the ScAlN film.

Abstract: A method for manufacturing a piezoelectric bulk acoustic wave element by forming a sacrificial layer on a part of a primary surface of a substrate. A piezoelectric film sandwiched between a pair of electrodes is formed on the primary surface of the substrate so as to cover the sacrificial layer, the piezoelectric film being formed from scandium-containing aluminum nitride having a scandium atomic concentration with respect to the total number of scandium atoms and aluminum atoms of more than 24 atomic percent. An etching step of removing the sacrificial layer by etching is performed. Prior to the etching step, a protective film formed from aluminum nitride or scandium-containing aluminum nitride having a lower scandium atomic concentration than that of the piezoelectric film is provided so as to cover at least a part of a portion of the piezoelectric film located in a region in which the sacrificial layer is provided.

Abstract: In a thin film device including a thin film electrode which has a main electrode layer formed of tungsten, a thin film electrode having a low resistivity is realized. There is provided a thin film device including a thin film electrode that has an underlayer and a main electrode layer formed on the underlayer. The underlayer is formed of a titanium-tungsten alloy having a crystalline structure with a wavy-like surface morphology, and the main electrode layer is formed of tungsten having a crystalline structure with a wavy-like surface morphology.

Abstract: A piezoelectric thin-film filter reduces insertion loss and deterioration of steepness of a shoulder characteristic and reduces the ripple in the passband. In a first vibration portion, a piezoelectric thin film is disposed between a pair of electrodes along one main surface of a substrate. In a second vibration portion, the piezoelectric thin film is disposed between a pair of electrodes along the one main surface of the substrate. The vibration portions are both acoustically isolated from the substrate. In the first resonator, an additional film is disposed outside the electrode constituting half or more the overall length of the perimeter of the first vibration portion that is in contact with the electrode when seen from a thickness direction. In the second resonator, the external shape of the vibration portion when seen from a thickness direction is a polygon, and each side of the polygon is not parallel with any of the other sides thereof.

Abstract: A variable capacitance device includes a substrate, a beam portion, lower drive electrodes and upper drive electrodes. The beam portion is made of an insulating material and is connected to the substrate via an anchor portion. In the lower drive electrode and the upper drive electrode, electrostatic attraction generated by the application of a DC voltage continuously changes. In the lower drive electrodes and the upper drive electrode, electrostatic capacitance generated by the application of an RF signal between the electrodes on both sides continuously changes in accordance with the deformation of the beam portion due to the electrostatic attraction. The beam portion includes an inner circumferential portion including the upper drive electrode, an outer circumferential portion including the upper drive electrode, and ladder portions sandwiched by the inner circumferential portion and the outer circumferential portion. The beam portion has a cross-sectional area that is reduced by the ladder portions.

Abstract: A variable capacitance device that operates properly at a point along a signal line through which a high-voltage RF signal passes while reducing a necessary DC voltage includes a substrate, a beam, and lower drive electrodes. The beam is connected to the substrate through a support portion. Lower drive electrodes and the beam generate a capacitance when a DC voltage is applied, and an electrostatic force due to this capacitance deforms the beam. The lower drive electrodes face the beam and are coupled to each other through the beam. An RF signal propagates between the lower drive electrodes.

Abstract: A duplexer that achieves a reduction in the size and an increase in the performance includes a transmission filter including piezoelectric thin film resonators and a reception filter including piezoelectric thin film resonators and an elastic wave resonator. The piezoelectric thin film resonators of the transmission filter and the piezoelectric thin film resonators and the elastic wave resonator of the reception filter are provided on the same substrate.