A piezoelectric element includes a first electrode layer, a piezoelectric layer, and a second electrode layer. The first electrode layer, the piezoelectric layer, and the second electrode layer are stacked in sequence on one another. The first electrode layer has a first part overlapping the piezoelectric layer in a plan view, and a second part at least partially separated from the first part and not overlapping the piezoelectric layer in the plan view. The second electrode layer has a third part overlapping the piezoelectric layer in the plan view, and a fourth part separated from the third part. The fourth part is in contact with the first part and the second part.

A subtractive forming method for piezoresistive material stacks includes applying an etch chemistry to an exposed first portion of a piezoresistive material stack. The etch chemistry includes a citric acid component for removing a first element of a piezoelectric layer of the piezoresistive material stack selectively to a surface oxide. At least one second element of the piezoelectric layer remains. The method further includes heating the piezoresistive material stack after said applying the etch chemistry to vaporize the at least one second element. A second portion of the piezoresistive material stack is protected from the removal and the heating by a mask.

In a non-limiting embodiment, a device may include a substrate, and a hybrid active structure disposed over the substrate. The hybrid active structure may include an anchor region and a free region. The hybrid active structure may be connected to the substrate at least at the anchor region. The anchor region may include at least a segment of a piezoelectric stack portion. The piezoelectric stack portion may include a first electrode layer, a piezoelectric layer over the first electrode layer, and a second electrode layer over the piezoelectric layer. The free region may include at least a segment of a mechanical portion. The piezoelectric stack portion may overlap the mechanical portion at edges of the piezoelectric stack portion.

A method for processing a lithium tantalate crystal substrate includes providing a lithium tantalate crystal substrate, roughening the lithium tantalate crystal substrate, providing a catalytic agent, bringing the lithium tantalate crystal substrate and the catalytic agent into contact with each other after the lithium tantalate crystal substrate is roughened, and subjecting the lithium tantalate crystal substrate to a reduction treatment. The reduction treatment is conducted at a temperature not higher than a Curie temperature of the lithium tantalate crystal substrate. The catalytic agent is selected from the group consisting of metal powder, metal gas, and metal carbonate powder.

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 manufacture for an acoustic resonator device. The method can include forming a topside metal electrode overlying a piezoelectric substrate with a piezoelectric layer and a seed substrate. A topside micro-trench can be formed within the piezoelectric layer and a topside metal can be formed overlying the topside micro-trench. This topside metal can include a topside metal plug formed within the topside micro-trench. A first backside trench can be formed underlying the topside metal electrode, and a second backside trench can be formed underlying the topside micro-trench. A backside metal electrode can be formed within the first backside trench, while a backside metal plug can be formed within the second backside trench and electrically coupled to the topside metal plug and the backside metal electrode. The topside micro-trench, the topside metal plug, the second backside trench, and the backside metal plug form a micro-via.

A method for fabricating an array of front ends for an array of packaged electronic components that each comprise:

an electrical element packaged within a package comprising
a front part of a package comprising an inner section with a cavity therein opposite the resonator defined by the raised frame and an outer section sealing said cavity; and
a back part of the package comprising a back cavity in an inner back section, and an outer back section sealing the cavity, said back package further comprising a first and a second via through the back end around said at least one back cavity for coupling to front and back electrodes of the electronic component; the vias terminating in external contact pads that are coupleable in a flip chip configuration to a circuit board; the method comprising the stages of: i. Obtaining a carrier substrate having an active membrane layer attached thereto by its rear surface, with a front electrode on the front surface of the active membrane layer; ii. Obtaining an inner front end section; iii. Attaching the inner front end section to the exposed front surface of the front electrode; iv. Detaching the carrier substrate from the rear surface of the active membrane layer; v. Optionally thinning the inner front section; vi. Processing the rear surface by removing material to create an array of at least one island of active membrane on at least one island of front electrode; vii. Creating an array of at least one front cavity by selectively removing at least outer layer of the inner front end section, such that there is one cavity opposite each island of membrane on the front side of the front electrode on the opposite side to the island of active membrane; viii. Applying an outer front end section to the inner front end section and bonding the outer front end section to an outer surface of the inner front end section such that the outer front end section spans across and seals the at least one cavity of the array of front cavities.

A touch control structure and a manufacturing method thereof, and a display device. The manufacturing method of the touch control structure includes providing a thin film substrate; providing a base substrate, and affixing the thin film substrate on the base substrate; forming a laminate structure on the thin film substrate for implementation of touch control functions; removing the thin film substrate with the laminate structure formed on top thereof from the base substrate.

A method of forming a piezoelectric microphone with an interlock/stopper and a micro-bump and a resulting device are provided. Embodiments include forming a membrane over a Si substrate having a first and second sacrificial layer disposed on opposite surfaces thereof, the membrane being formed on the first sacrificial layer, forming a first HM over the membrane, forming first and second vias through the first HM, forming a first pad layer in the first and second vias and over an exposed top thin film, forming a trench to the first sacrificial layer between the first and second vias and a gap between the trench and second via, patterning a second HM over the membrane, in the first and second vias, the trench and the gap, and forming a second pad layer over the second HM and in exposed areas around the first and second vias to form pad structures.

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.