A BAW component, a lamination for a BAW component, and a method for manufacturing a BAW component are provided. A lamination for a BAW component includes a first layer with a first piezoelectric material and a second layer with a second piezoelectric material that is different than the first piezoelectric material. The first and the second piezoelectric material can be Sc doped AlN and AlN, respectively.

A vibration element includes: a quartz crystal substrate having a first vibration part and a second vibration part; a pair of first excitation electrodes formed at two main surfaces of the quartz crystal substrate, at the first vibration part; and a pair of second excitation electrodes formed in such a way as to sandwich the second vibration part in a direction of thickness of the quartz crystal substrate, at the second vibration part. At least one second excitation electrode of the pair of second excitation electrodes is formed at an inclined surface inclined to at least one of the two main surfaces.

A piezoelectric vibration member that includes a substrate having a main surface on or in which a piezoelectric vibration member is mounted, a lid having a recess that is open so as to face the main surface and which includes a flange portion that projects outward from an opening edge of the recess, and a bonding layer that bonds the substrate and the lid together so as to hermetically seal the piezoelectric vibrator in a space between the recess and the main surface. The surface roughness of a side surface of the flange portion is greater than the surface roughness of the surface of the recess, and the bonding layer extends from the main surface of the substrate to the side surface of the flange portion.

A piezoelectric film that includes crystalline AlN; at least one first element partially replacing Al in the crystalline AlN; and a second element doping the crystalline AlN and which has an ionic radius smaller than that of the first element and larger than that of Al.

Described herein is a method of bonding a piezoelectric substrate to a support substrate to form a composite substrate. The piezoelectric substrate has one surface which is positively polarized, and a second surface which is negatively polarized. The method described herein includes the steps of bonding the positively polarized surface of the piezoelectric substrate to one surface of the support substrate by a direct bonding method.

Filter devices and methods are disclosed. A filter device includes a substrate having a surface. A back surface of a single-crystal piezoelectric plate is attached to the surface of the substrate, portions of the single-crystal piezoelectric plate forming a plurality of diaphragms spanning respective cavities in the substrate. A conductor pattern is formed on a front surface of the piezoelectric plate, the conductor pattern including a plurality of interdigital transducers (IDTs) of a plurality of resonators. Interleaved fingers of at least a first IDT of the plurality of IDTs are disposed on a diaphragm having a first thickness, and interleaved fingers of at least a second IDT of the plurality of IDTs are disposed on a diaphragm having a second thickness less than the first thickness.

In some examples, an apparatus includes a first metal layer having a thickness, a piezoelectric material layer having a first side and a second side that is opposite the first side, the piezoelectric material layer first side abutting the first metal layer, the piezoelectric material layer second side having recesses, and a second metal layer abutting the piezoelectric material layer second side, the second metal layer having extensions that fill the recesses to form a metal frame that is at least partially recessed into the piezoelectric material layer. The first metal layer, the piezoelectric material layer, and the second metal layer form a resonator body. The metal frame has a shape governing a resonant mode of the resonator body.

Filters and methods of making filters are disclosed. A filter device includes a substrate, a piezoelectric plate, and an acoustic Bragg reflector between a surface of the substrate and a back surface of the piezoelectric plate. A first portion of the piezoelectric plate has a first thickness, and a second portion of the piezoelectric plate has a second thickness less than the first thickness. A conductor pattern on front surfaces of the first and second portions of the piezoelectric plate includes a first interdigital transducer (IDT) with interleaved fingers on the first portion, and a second IDT with interleaved fingers on the second portion.

Techniques are disclosed for forming integrated circuit film bulk acoustic resonator (FBAR) devices having multiple resonator thicknesses on a common substrate. A piezoelectric stack is formed in an STI trench and overgrown onto the STI material. In some cases, the piezoelectric stack can include epitaxially grown AlN. In some cases, the piezoelectric stack can include single crystal (epitaxial) AlN in combination with polycrystalline (e.g., sputtered) AlN. The piezoelectric stack thus forms a central portion having a first resonator thickness and end wings extending from the central portion and having a different resonator thickness. Each wing may also have different thicknesses from one another. Thus, multiple resonator thicknesses can be achieved on a common substrate, and hence, multiple resonant frequencies on that same substrate. The end wings can have metal electrodes formed thereon, and the central portion can have a plurality of IDT electrodes patterned thereon.

A microelectromechanical resonator device is provided having two-dimensional resonant rods. The resonator device has a piezoelectric layer formed with a plurality of alternating rods and trenches. A bottom electrode is in contact with a bottom surface of the piezoelectric layer. A top electrode metal grating of conductive strips is aligned in contact with corresponding rods of the piezoelectric layer.