In some embodiments, the present disclosure relates to a method in which a first set of one or more voltage pulses is applied to a piezoelectric device over a first time period. During the first time period, the method determines whether a performance parameter of the piezoelectric device has a first value that deviates from a reference value by more than a predetermined value. Based on whether the first value deviates from the reference value by more than the predetermined value, the method selectively applies a second set of one or more voltage pulses to the piezoelectric device over a second time period. The second time period is after the first time period and the second set of one or more voltage pulses differs in magnitude and/or polarity from the first set of one or more voltage pulses.

The present invention relates to a energy conversion device (100) configured to convert a light signal into an electrical signal, comprising: an actuator element (50), substantially planar, having at least one activatable portion (30), said activatable portion comprising a photomobile polymeric material; a transducer element (60), substantially planar, having at least a portion of piezoelectric material; wherein said actuator element (50) is coupled to said transducer element (60) so that, at a light beam incident on said photomobile polymeric material, a movement of said transducer element (60) is activated through a movement of said activatable portion (30), said movement of said transducer element (60) providing the generation of a potential difference at the terminal ends of said portion of piezoelectric material.

The present invention also relates to a method of production of the aforesaid device.

There is provided a piezoelectric stack, including: a substrate; an electrode film; and a piezoelectric film which is comprised of alkali niobium oxide of a perovskite structure represented by a composition formula of (K.sub.1-xNa.sub.x)NbO.sub.3 (0<x<1), wherein the piezoelectric film comprises crystals having a grain size with a standard deviation of 0.42 m or less.

There is provided a piezoelectric stack, including: a substrate; an electrode film; and a piezoelectric film which is comprised of alkali niobium oxide of a perovskite structure represented by a composition formula of (K.sub.1-xNa.sub.x)NbO.sub.3 (0<x<1), wherein the piezoelectric film comprises crystals having a grain size with a standard deviation of more than 0.42 m.

A method of forming a monolithic integrated PMUT and CMOS with a coplanar elastic, sealing, and passivation layer in a single step without bonding and the resulting device are provided. Embodiments include providing a CMOS wafer with a metal layer; forming a dielectric over the CMOS; forming a sacrificial structure in a portion of the dielectric; forming a bottom electrode; forming a piezoelectric layer over the CMOS; forming a top electrode over portions of the bottom electrode and piezoelectric layer; forming a via through the top electrode down to the bottom electrode and a second via down to the metal layer through the top electrode; forming a second metal layer over and along sidewalls of the first and second via; removing the sacrificial structure, an open cavity formed; and forming a dielectric layer over a portion of the CMOS, the open cavity sealed and an elastic layer and passivation formed.

Techniques are disclosed for monolithic co-integration of thin-film bulk acoustic resonator (TFBAR, also called FBAR) devices and III-N semiconductor transistor devices. In accordance with some embodiments, one or more TFBAR devices including a polycrystalline layer of a piezoelectric III-N semiconductor material may be formed alongside one or more III-N semiconductor transistor devices including a monocrystalline layer of III-N semiconductor material, over a commonly shared semiconductor substrate. In some embodiments, either (or both) the monocrystalline and the polycrystalline layers may include gallium nitride (GaN), for example. In accordance with some embodiments, the monocrystalline and polycrystalline layers may be formed simultaneously over the shared substrate, for instance, via an epitaxial or other suitable process. This simultaneous formation may simplify the overall fabrication process, realizing cost and time savings, at least in some instances.

A microelectromechanical system (MEMS) resonator includes a degenerately-doped single-crystal silicon layer and a piezoelectric material layer disposed on the degenerately-doped single-crystal silicon layer. An electrically-conductive material layer is disposed on the piezoelectric material layer opposite the degenerately-doped single-crystal silicon layer, and patterned to form first and second electrodes.

There is provided a piezoelectric laminate, including: a substrate; a base layer formed on the substrate; and a piezoelectric film containing alkali niobium oxide and having a perovskite structure, which is formed on the base layer, as a polycrystalline film, and represented by a composition formula of (K.sub.1-xNa.sub.x)NbO.sub.3 (0<x<1), wherein a crystal grain group forming the piezoelectric film includes a crystal grain having a ratio of 0.01 nm.sup.1 or more and 0.1 nm.sup.1 or less, which is the ratio of an outer peripheral length to a cross-sectional area when observing a cross-section of the crystal grain.

A method for producing an ultrasonic transducer or ultrasonic transducer array, the method comprising providing or depositing a layer of piezoelectric material on a substrate. The piezoelectric material is a doped, co-deposited or alloyed piezoelectric material. The piezoelectric material comprises: a doped, co-deposited or alloyed metal oxide or metal nitride, the metal oxide or metal nitride being doped, co-deposited or alloyed with vanadium or a compound thereof; or zinc oxide doped, co-deposited or alloyed with a transition metal or a compound thereof. Optionally, the deposition of the layer of piezoelectric material is by sputter coating, e.g. using a sputtering target that comprises a doped or alloyed piezoelectric material. In examples, the layer of piezoelectric material is deposited onto the substrate using high power impulse magnetron sputtering (HIPIMS). Further enhancement may be obtained using substrate biasing (e.g. DC and/or RF) during deposition of the layer of piezoelectric material. In further examples, the substrate is provided on a rotating drum whilst tire layer of piezoelectric material is being deposited.

A first organic resin layer is formed over a first substrate; a first insulating film is formed over the first organic resin layer; a first element layer is formed over the first insulating film; a second organic resin layer is formed over a second substrate; a second insulating film is formed over the second organic resin layer; a second element layer is formed over the second insulating film; the first substrate and the second substrate are bonded; a first separation step in which adhesion between the first organic resin layer and the first substrate is reduced; the first organic resin layer and a first flexible substrate are bonded with a first bonding layer; a second separation step in which adhesion between the second organic resin layer and the second substrate is reduced; and the second organic resin layer and a second flexible substrate are bonded with a second bonding layer.