A composite substrate according to includes: a support substrate; and a piezoelectric layer arranged on one side of the support substrate, wherein an amplitude of a waviness having a spatial frequency of more than 0.045 cyc/mm according to a shape of the support substrate is 10 nm or less.

A composite substrate includes in this order: a support substrate; an intermediate layer; and a piezoelectric layer, wherein the intermediate layer contains bubbles.

A method of printing comprises providing a component source wafer comprising components, a transfer device, and a patterned substrate. The patterned substrate comprises substrate posts that extend from a surface of the patterned substrate. Components are picked up from the component source wafer by adhering the components to the transfer device. One or more of the picked-up components are printed to the patterned substrate by disposing each of the one or more picked-up components onto one of the substrate posts, thereby providing one or more printed components in a printed structure.

A microphone device may include: a substrate wafer, a support member bonded to a front surface of the substrate wafer, a single-crystal piezoelectric film provided over the support member, a top electrode and a bottom electrode. The single-crystal piezoelectric film may have a first surface and an opposing second surface. The top electrode may be arranged adjacent to the first surface of the single-crystal piezoelectric film. The bottom electrode may be arranged adjacent to the second surface of the single-crystal piezoelectric film. The substrate wafer may have a through-hole formed therein. The through-hole of the substrate wafer may be at least substantially aligned with at least one of the top electrode and the bottom electrode.

In a piezoelectric device, when viewed in a direction perpendicular to one main surface, an outer shape of a recess is a polygonal shape or a circular shape. When n represents a number of sides of the polygonal shape, r represents a radius of a circumscribed circle of an imaginary regular polygon including n sides with a length identical to a length of a shortest of the sides, and d represents a maximum thickness of a membrane portion, which is located above the recess, of a multilayer portion, r≤197.7dn.sup.−0.6698 when 3≤n≤7, and r≤52.69d when 8≤n or when the outer shape of the recess is a circular shape.

A bonded body has a supporting substrate composed of silicon, piezoelectric material substrate, and a bonding layer provided on a bonding surface of the supporting substrate and composed of a metal oxide. An amount of aluminum atoms on the bonding surface of the supporting substrate is 1.0×10.sup.11 to 1.0×10.sup.15 atoms/cm.sup.2.

A liquid discharge head includes a flow passage member, a sealing member, and an actuator member. The flow passage member is formed with individual flow passages each including a nozzle and a pressure chamber and the flow passage member has a surface on which the pressure chamber is open. The sealing member is arranged on the surface and seals the pressure chamber. The actuator member has a piezoelectric layer, a driving electrode, and a high electric potential portion. The piezoelectric layer is adhered to a first surface of the sealing member on a side opposite to the flow passage member, via a first adhesive having an insulating property. The driving electrode is arranged on a side opposite to the sealing member with respect to the piezoelectric layer at a position overlapped with the pressure chamber in a first direction orthogonal to the surface.

The invention relates to a method for transferring at least one layer of material, comprising: producing first and second separating layers (108, 110), one against the other, on a first substrate (104); producing the layer to be transferred on the second separating layer (110); securing the layer to be transferred to a second substrate (106), forming a stack of different materials; and performing mechanical separation at the interface between the separating layers; in which the materials of the stack are such that the interface between the first and second separating layers has the weakest adhesion force, and the method comprises a step reducing an initial adhesion force of the interface between the first and second separating layers.

In a chip-on-array approach, acoustic and electronic modules are separately formed. The acoustic stack is connected to one interposer, and the electronics are connected to another interposer. Different connection processes (e.g., using low temperature bonding for the acoustic stack and higher temperature-based interconnect for the electronics) may be used. This arrangement may allow for different pitches of the transducer elements and the I/O of the electronics by staggering vias in the interposers. The two interposers are then connected to form the chip-on-array.

A method of forming a microphone device includes: forming a through-hole in a substrate wafer; providing a second wafer; bonding the second wafer to the substrate wafer; and forming a top electrode over a first surface of a single-crystal piezoelectric film of the second wafer. The second wafer may include the single-crystal piezoelectric film. The single-crystal piezoelectric film may have a first surface and an opposing second surface. The second wafer may further include a bottom electrode arranged adjacent to the second surface, and a support member over the single-crystal piezoelectric film. The through-hole in substrate wafer may be at least substantially aligned with at least one of the top electrode and the bottom electrode.