A device may include a substrate that includes a base and an intermediate layer. A device may include a piezoelectric layer supported by the substrate except for a portion of the piezoelectric layer forming a diaphragm that spans a helium filled cavity that extends at least partially in the intermediate layer. A device may include an interdigital transducer (IDT) at a surface of the piezoelectric layer and having interleaved fingers on the diaphragm that have a thickness that is less than 0.5 times a thickness of the diaphragm and greater than 0.2 times the thickness of the diaphragm, wherein one of the base and the intermediate layer of the substrate defines a bottom surface of the helium filled cavity that faces the diaphragm such that a cavity depth is between 1.0 m to 6.0 m.

An acoustic resonator device is provided that a piezoelectric layer; an interdigital transducer on a surface of the piezoelectric layer and including interleaved IDT fingers extending from first and second busbars respectively; and a metal layer disposed between a finger of the interleaved IDT fingers and the piezoelectric layer in a thickness direction that is measured in a direction normal to the surface of the piezoelectric layer. In this aspect, a ratio of a width of the metal layer to a pitch of the interleaved IDT fingers is greater than or equal to 0.45, the width of the metal layer being measured in a width direction that is parallel to the surface of the piezoelectric layer. Moreover, a thickness of the metal layer in the thickness direction is less than one third a thickness of the finger in the thickness direction.

The present disclosure relates to an electronic element package and a method of manufacturing the same. The electronic element package includes a substrate, an element disposed on the substrate, and a cap enclosing the element. One of the substrate and the cap includes a groove, the other of the substrate and the cap includes a protrusion engaging with the groove. A first metal layer and a second metal layer form a metallic bond with each other in a space between the groove and the protrusion.

An acoustic wave filter includes series resonators and parallel resonators that have a piezoelectric film on an identical substrate and have a lower electrode and an upper electrode, wherein: one of the series resonators and the parallel resonators have a temperature compensation film on a face of the lower electrode or the upper electrode that is opposite to the piezoelectric film in a resonance region, the compensation film having an elastic constant of a temperature coefficient of which sign is opposite to a sign of a temperature coefficient of an elastic constant of the piezoelectric film; and the other have an added film on the same side as the temperature compensation film on the lower electrode side or the upper electrode side compared to the piezoelectric film in the resonance region in the one of the series resonators and the parallel resonators.

Disclosed is a bulk acoustic wave resonator (BAWR). The BAWR includes a bulk acoustic wave resonance unit with a first electrode, a second electrode, and a piezoelectric layer. The piezoelectric layer is disposed between the first electrode and the second electrode. An air edge is formed at a distance from a center of the bulk acoustic wave resonance unit.

A film bulk acoustic resonator (FBAR) and a method of fabricating the FBAR are disclosed. In the method, formation of several mutually overlapped and hence connected sacrificial material layers above and under a resonator sheet facilitates the removal of the sacrificial material layers. Cavities left after the removal overlap at a polygonal area with non-parallel sides. This reduces the likelihood of boundary reflections of transverse parasitic waves causing standing wave resonance in the FBAR, thereby enhancing its performance in parasitic wave crosstalk. Further, according to the invention, the FBAR is enabled to be integrated with CMOS circuitry and hence exhibits higher reliability.

An acoustic wave filter includes series resonators and parallel resonators that have a piezoelectric film on an identical substrate and have a lower electrode and an upper electrode, wherein: one of the series resonators and the parallel resonators have a temperature compensation film on a face of the lower electrode or the upper electrode that is opposite to the piezoelectric film in a resonance region, the compensation film having an elastic constant of a temperature coefficient of which sign is opposite to a sign of a temperature coefficient of an elastic constant of the piezoelectric film; and the other have an added film on the same side as the temperature compensation film on the lower electrode side or the upper electrode side compared to the piezoelectric film in the resonance region in the one of the series resonators and the parallel resonators.

In a method of manufacturing a piezoelectric device in which a piezoelectric thin film on which functional conductors are formed is fixed to a support substrate by a fixing layer, an alignment mark is formed on one main surface of a light-transmitting piezoelectric substrate. A sacrificial layer is formed on a main surface of the piezoelectric substrate with reference to the alignment mark and the fixing layer is formed so as to cover the sacrificial layer and is bonded to the support substrate. The piezoelectric thin film is formed by being separated from the piezoelectric substrate and the functional conductors are formed on the surface of the piezoelectric thin film with reference to the alignment mark. The piezoelectric device is able to be manufactured while positions of formation regions of conductors are adjusted efficiently.

An acoustic resonator and a method of manufacturing the same are provided. The acoustic resonator includes a resonating part including a first electrode, a second electrode, and a piezoelectric layer; and a plurality of seed layers disposed on one side of the resonating part.

A method is provided for fabricating a bulk acoustic wave (BAW) resonator device. The method includes forming an etch stop layer over a bottom electrode and a substrate; forming a dielectric layer on the etch stop layer; forming a photomask over the dielectric layer defining an opening over the bottom electrode; etching a portion the dielectric layer through the opening of the photomask to the etch stop layer to create a corresponding opening in the dielectric layer; removing the photomask, leaving un-etched protruding portions of the dielectric layer around the opening in the dielectric layer; and removing the protruding portions of the dielectric layer, a portion of the etch stop layer located over the bottom electrode, and a minimal portion of the bottom electrode to provide a planarized surface including a top surface of the bottom electrode and an adjacent top surface of the dielectric layer deposited over the substrate.