A method for manufacturing a composite substrate includes: forming a first intermediate layer including thermally synthesized silica on a surface of a support substrate; forming a second intermediate layer including an inorganic material on a surface of a piezoelectric single crystal substrate; flattening a surface of the second intermediate layer; and bonding a surface of the first intermediate layer to the flattened surface of the second intermediate layer.

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 bonded body includes a supporting substrate, a silicon oxide layer provided on the supporting substrate, and a piezoelectric material substrate provided on the silicon oxide layer and composed of a material selected from the group consisting of lithium niobate, lithium tantalate and lithium niobate-lithium tantalate. The surface resistivity of the piezoelectric material substrate on the side of the silicon oxide layer is 1.710.sup.1 5/ or higher.

A bonded body includes a supporting substrate, a silicon oxide layer provided on the supporting substrate, and a piezoelectric material substrate provided on the silicon oxide layer and composed of a material selected from the group consisting of lithium niobate, lithium tantalate and lithium niobate-lithium tantalate. The surface resistivity of the piezoelectric material substrate on the side of the silicon oxide layer is 1.710.sup.1 5/ or higher.

A process for fabricating a substrate for a radiofrequency device by joining a piezoelectric layer to a carrier substrate by way of an electrically insulating layer, the piezoelectric layer having a rough surface at its interface with the electrically insulating layer, the process being characterized in that it comprises the following steps: providing a piezoelectric substrate having a rough surface for reflecting a radiofrequency wave, depositing a dielectric layer on the rough surface of the piezoelectric substrate, providing a carrier substrate, depositing a photo-polymerizable adhesive layer on the carrier substrate, bonding the piezoelectric substrate to the carrier substrate by way of the dielectric layer and of the adhesive layer, in order to form an assembled substrate, irradiating the assembled substrate with a light flux in order to polymerize the adhesive layer, the adhesive layer and the dielectric layer together forming the electrically insulating layer.

A process for fabricating a substrate for a radiofrequency device by joining a piezoelectric layer to a carrier substrate by way of an electrically insulating layer, the piezoelectric layer having a rough surface at its interface with the electrically insulating layer, the process being characterized in that it comprises the following steps: providing a piezoelectric substrate having a rough surface for reflecting a radiofrequency wave, depositing a dielectric layer on the rough surface of the piezoelectric substrate, providing a carrier substrate, depositing a photo-polymerizable adhesive layer on the carrier substrate, bonding the piezoelectric substrate to the carrier substrate by way of the dielectric layer and of the adhesive layer, in order to form an assembled substrate, irradiating the assembled substrate with a light flux in order to polymerize the adhesive layer, the adhesive layer and the dielectric layer together forming the electrically insulating layer.

A multilayer actuator includes a primary electrode, a secondary electrode overlapping at least a portion of the primary electrode, and an electroactive layer disposed between and abutting the primary electrode and the secondary electrode. The multilayer actuator further includes a primary antireflective coating overlapping at least a portion of the primary electrode opposite the electroactive layer, a secondary antireflective coating overlapping at least a portion of the secondary electrode opposite the electroactive layer, and a barrier layer overlapping the secondary antireflective coating opposite the secondary electrode.

A multilayer actuator includes a primary electrode, a secondary electrode overlapping at least a portion of the primary electrode, and an electroactive layer disposed between and abutting the primary electrode and the secondary electrode. The multilayer actuator further includes a primary antireflective coating overlapping at least a portion of the primary electrode opposite the electroactive layer, a secondary antireflective coating overlapping at least a portion of the secondary electrode opposite the electroactive layer, and a barrier layer overlapping the secondary antireflective coating opposite the secondary electrode.

A bonded body includes a supporting substrate, a silicon oxide layer provided on the supporting substrate, and a piezoelectric material substrate provided on the silicon oxide layer and composed of a material selected from the group consisting of lithium niobate, lithium tantalate and lithium niobate-lithium tantalate. The surface resistivity of the piezoelectric material substrate on the side of the silicon oxide layer is 1.710.sup.1 5/ or higher.

The present invention relates to a heterostructure, in particular, a piezoelectric structure, comprising a cover layer, in particular, a layer of piezoelectric material, the material of the cover layer having a first coefficient of thermal expansion, assembled to a support substrate, the support substrate having a second coefficient of thermal expansion substantially different from the first coefficient of thermal expansion, at an interface wherein the cover layer comprises at least a recess extending from the interface into the cover layer, and its method of fabrication.