A bonded structure is disclosed. The bonded structure includes a first element and a second element that is bonded to the first element along a bonding interface. The bonding interface has an elongate conductive interface feature and a nonconductive interface feature. The bonded structure also includes an integrated device that is coupled to or formed with the first element or the second element. The elongate conductive interface feature has a recess through a portion of a thickness of the elongate conductive interface feature. A portion of the nonconductive interface feature is disposed in the recess.

In a general aspect, a vapor cell is presented that includes a dielectric body. The dielectric body has a surface that defines an opening to a cavity in the dielectric body. The vapor cell also includes a vapor or a source of the vapor in the cavity of the dielectric body. An optical window covers the opening of the cavity and has a surface bonded to the surface of the dielectric body to form a seal around the opening. The seal includes metal-oxygen bonds formed by reacting a first plurality of hydroxyl ligands on the surface of the dielectric body with a second plurality of hydroxyl ligands on the surface of the optical window.

A micro electro mechanical system (MEMS) includes a circuit substrate, a first MEMS structure disposed over the circuit substrate, and a second MEMS structure disposed over the first MEMS structure.

A micro-electro-mechanical sensor comprises a first substrate comprising an element movable with respect to the first substrate and a second substrate comprising a first contact pad and a second contact pad. The first substrate is bonded to the second substrate such that a movement of the element changes a coupling between the first contact pad and the second contact pad.

A method includes fusion bonding a first side of a MEMS wafer to a second side of a first handle wafer. A TSV is formed from a first side of the first handle wafer to the second side of the first handle wafer and into the first MEMS wafer. A dielectric layer is formed on the first side of the first handle wafer. A tungsten via is formed in the dielectric layer. Electrodes are formed on the dielectric layer. A second MEMS wafer is eutecticly bonded with a first eutectic bond to the electrodes, wherein the TSV electrically connects the first MEMS wafer to the second MEMS wafer. Standoffs are formed on a second side of the first MEMS wafer. A CMOS wafer is eutecticly bonded with a second eutectic bond to the standoffs, wherein the second eutectic bond includes different materials than the first eutectic bond.

Representative implementations of techniques and devices provide seals for sealing the joints of bonded microelectronic devices as well as bonded and sealed microelectronic assemblies. Seals are disposed at joined surfaces of stacked dies and wafers to seal the joined surfaces. The seals may be disposed at an exterior periphery of the bonded microelectronic devices or disposed within the periphery using the various techniques.

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.

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.

In described examples, a first metal layer is configured along a periphery of a cavity to be formed between a first substrate and a second substrate. A second metal layer is adjacent the first metal layer. The second metal layer includes a cantilever. The cantilever is configured to deform by bonding the first substrate to the second substrate. The deformed cantilevered is configured to impede contaminants against contacting an element within the cavity.

In a general aspect, a vapor cell is presented that includes a dielectric body. The dielectric body has a surface that defines an opening to a cavity in the dielectric body. The vapor cell also includes a vapor or a source of the vapor in the cavity of the dielectric body. An optical window covers the opening of the cavity and has a surface bonded to the surface of the dielectric body to form a seal around the opening. The seal includes metal-oxygen bonds formed by reacting a first plurality of hydroxyl ligands on the surface of the dielectric body with a second plurality of hydroxyl ligands on the surface of the optical window.