Processes for fabricating capacitive micromachined ultrasonic transducers (CMUTs) are described, as are CMUTs of various doping configurations. An insulating layer separating conductive layers of a CMUT may be formed by forming the layer on a lightly doped epitaxial semiconductor layer. Dopants may be diffused from a semiconductor substrate into the epitaxial semiconductor layer, without diffusing into the insulating layer. CMUTs with different configurations of N-type and P-type doping are also described.

A system includes a semiconductor substrate having a first cavity. The semiconductor substrate forms a pedestal adjacent the first cavity. A device overlays the pedestal and is bonded to the semiconductor substrate by metal within the first cavity. A plurality of second cavities are formed in a surface of the pedestal beneath the device, wherein the second cavities are smaller than the first cavity. In some of these teachings, the second cavities are voids. In some of these teachings, the metal in the first cavity comprises a eutectic mixture. The structure relates to a method of manufacturing in which a layer providing a mask to etch the first cavity is segmented to enable easy removal of the mask-providing layer from the area over the pedestal.

The invention includes a method of promoting interfacial mechanical bonding of two or more components through the use of suspended and/or freestanding structures fabricated using an atom-scale assembly process on at least a portion of the surfaces of such components.

In a semiconductor device, a first substrate and a second substrate are bonded to each other through an insulating film. A hermetically sealed chamber is provided between the first substrate and the second substrate, and a sensing part is enclosed in the hermetically sealed chamber. The second substrate has a through hole penetrating in a stacking direction of the first substrate and the second substrate and exposing the first surface of the first substrate. A penetrating electrode is disposed on a wall surface of the through hole of the second substrate, and is electrically connected to the sensing part. A discharge path is provided, at a position located between the hermetically sealed chamber and the through hole for releasing outgas generated during bonding from the hermetically sealed chamber to the through hole.

A semiconductor layer having an opening and a MEMS resonator formed in the opening is disposed between first and second substrates to encapsulate the MEMS resonator. An electrical contact that extends from the opening to an exterior of the MEMS device is formed at least in part within the semiconductor layer and at least in part within the first substrate.

In described examples, a first metal layer is arranged along a periphery of a cavity to be formed between a first substrate and a second substrate. A second metal layer is arranged adjacent to the first metal layer, where the second metal layer includes a cantilever. The cantilever is arranged to deform in response to forces applied from a contacting structure of the second substrate during bonding of the first substrate to the second substrate. The deformed cantilevered is arranged to impede contaminants against contacting an element within the cavity.

A microelectro-mechanical system (MEMS) device includes a substrate of a semiconductor material having thereon a movable component, a glass substrate bonded to the substrate, an electrostatic biasing layer disposed between the movable component and the glass substrate. A cavity is defined between the movable component and a top surface of the glass substrate. The electrostatic biasing layer completely overlaps with the movable component.

In described examples, a first metal layer is arranged along a periphery of a cavity to be formed between a first substrate and a second substrate. A second metal layer is arranged adjacent to the first metal layer, where the second metal layer includes a cantilever. The cantilever is arranged to deform in response to forces applied from a contacting structure of the second substrate during bonding of the first substrate to the second substrate. The deformed cantilevered is arranged to impede contaminants against contacting an element within the cavity.

A method of processing a double sided wafer of a microelectromechanical device includes spinning a resist onto a first side of a first wafer. The method further includes forming pathways within the resist to expose portions of the first side of the first wafer. The method also includes etching one or more depressions in the first side of the first wafer through the pathways, where each of the depressions have a planar surface and edges. Furthermore, the method includes depositing one or more adhesion metals over the resist such that the one or more adhesion metals are deposited within the depressions, and then removing the resist from the first wafer. The method finally includes depositing indium onto the adhesion metals deposited within the depressions and bonding a second wafer to the first wafer by compressing the indium between the second wafer and the first wafer.

A bonded structure can include a first element having a first interface feature and a second element having a second interface feature. The first interface feature can be bonded to the second interface feature to define an interface structure. A conductive trace can be disposed in or on the second element. A bond pad can be provided at an upper surface of the first element and in electrical communication with the conductive trace. An integrated device can be coupled to or formed with the first element or the second element.