Abstract: Methods for producing MEMS (microelectromechanical systems) devices with a thick active layer and devices produced by the method. An example method includes heavily doping a first surface of a first silicon wafer with P-type impurities, and heavily doping a first surface of a second silicon wafer with N-type impurities. The heavily doped first surfaces are then bonded together, and a second side of the first wafer opposing the first side of the first wafer is thinned to a desired thickness, which may be greater than about 30 micrometers. The second side is then patterned and etched, and the etched surface is then heavily doped with P-type impurities. A cover is then bonded to the second side of the first wafer, and the second wafer is thinned.

Abstract: A Micro-Electro-Mechanical System closed-loop (MEMS) inertial device having a vertical comb drive that exhibits improved performance under vibration. The device includes one or more stator tines extending from a housing into a cavity formed by the housing. One or more rotor tines extend from a proof mass located in the cavity. The proof mass is joined to the housing by flexures which allow movement in the vertical direction. The rotor tines have a first length value in the direction of movement and the stator tines have a second length value in the direction of movement. The second length value is greater than the first length value. Also, the stator tines include two electrically separated portions. The lesser length of the rotor tines relative to the stator tines causes the attractive force between the rotor tines and either the upper or lower half of the stator tines to be relatively independent of rotor vertical position. This, in turn, produces better accelerometer accuracy in vibration environments.

Abstract: Methods and systems for growing uniform oxide layers include an example method including growing a first layer of oxide on first and second facets of the substrate, with the first facet having a faster oxide growth rate. The oxide is removed from the first facet and a second oxide layer is grown on the first and second facets. Removing the oxide from the first facet includes shielding the second facet and exposing the substrate to a deoxidizing condition. The second facet is then exposed to receive the second oxide layer. Areas having differing oxide thicknesses are also grown by repeatedly growing oxide layers, selectively shielding areas, and removing oxide from exposed areas.

Abstract: A Micro-Electro-Mechanical System closed-loop (MEMS) inertial device having a vertical comb drive that exhibits improved performance under vibration. The device includes one or more stator tines extending from a housing into a cavity formed by the housing. One or more rotor tines extend from a proof mass located in the cavity. The proof mass is joined to the housing by flexures which allow movement in the vertical direction. The rotor tines have a first length value in the direction of movement and the stator tines have a second length value in the direction of movement. The second length value is greater than the first length value. Also, the stator tines include two electrically separated portions. The lesser length of the rotor tines relative to the stator tines causes the attractive force between the rotor tines and either the upper or lower half of the stator tines to be relatively independent of rotor vertical position. This, in turn, produces better accelerometer accuracy in vibration environments.

Abstract: A MEMS device having a proof mass resiliently mounted above a substrate has projections formed on adjacent surfaces of the mass and substrate. The device is formed by creating a plurality of holes in the upper layer. A substance suitable for removing the intermediate layer without substantially removing the upper layer and substrate is introduced through the holes. A substance removing the upper layer, the substrate, or both, is then introduced through the holes to remove a small amount of the substrate and upper layer. Portions of the intermediate layer between the projections are then removed. The dimple structure fabricated from this process will prevent MEMS device stiction both in its final release and device operation.

Abstract: A device and method for isolation of MEMS devices. A device includes a pair of substantially symmetrical wafers, each including a perimeter mounting flange and a cover plate, each cover plate and mounting flange separated by a plurality of tines. The cover plates of the wafers are bonded to the opposite sides of a device layer, and the system may then be bonded to other structures via the mounting flange. A method includes forming tines in a pair of wafers and bonding the wafers to opposite sides of a device layer. An alternative method includes bonding a pair of wafers to a device layer, then etching the isolation features.

Abstract: A method of manufacturing a vertical comb structure for a micro electromechanical (MEMS) device. Tooth structures are formed on a first wafer. A second wafer is then bonded to the tooth structures of the first wafer. The tooth structures are then released to form a comb structure. Forming the tooth structures on the first wafer includes using oxidation, photolithography, etching, epitaxy, and chemical and mechanical polishing to create the tooth structures on the first wafer.

Abstract: Methods and systems for growing uniform oxide layers include an example method including growing a first layer of oxide on first and second facets of the substrate, with the first facet having a faster oxide growth rate. The oxide is removed from the first facet and a second oxide layer is grown on the first and second facets. Removing the oxide from the first facet includes shielding the second facet and exposing the substrate to a deoxidizing condition. The second facet is then exposed to receive the second oxide layer. Areas having differing oxide thicknesses are also grown by repeatedly growing oxide layers, selectively shielding areas, and removing oxide from exposed areas.

Abstract: An apparatus and method for sensor architecture based on bulk machining of Silicon-On-Oxide wafers and fusion bonding that provides a symmetric, nearly all-silicon, hermetically sealed MEMS device having a sensor mechanism formed in an active semiconductor layer, and opposing silicon cover plates each having active layers bonded to opposite faces of the sensor mechanism. The mechanism is structured with sensor mechanical features structurally supported by at least one mechanism anchor. The active layers of the cover plates each include interior features structured to cooperate with the sensor mechanical features and an anchor structured to cooperate with the mechanism anchor. A handle layer of each cover plate includes a pit extending there through in alignment with the cover plate anchor. An unbroken rim of dielectric material forms a seal between the cover plate anchor and the pit and exposes an external surface of the cover plate anchor.

Abstract: Systems and methods for measuring thickness of an epitaxial layer grown on a silicon wafer. An oxide layer is generated on a side of the silicon wafer. One or more posts of oxide are created from the oxide layer by masking and removing unwanted oxide. An epitaxial layer is grown on the side of the silicon wafer over the one or more oxide posts. The epitaxial layer is removed in an area that includes at least the epitaxial layer grown on the one or more oxide posts. Then, the one or more oxide posts are removed. The thickness of the epitaxial layer is determined by measuring a distance along an axis between a surface of the silicon wafer where one of the one or more oxide posts previously attached and a top surface of the epitaxial layer, the axis being approximately perpendicular to the surface of the wafer.

Abstract: A sensor apparatus (104) includes a plural different spatial direction axis of sensitivity positioned sensor package containing sensor module (305) supported by a planar surface (345) within a cavity (340) of a housing (205) coupled to a first end cap (210) by a PC-board connection (355). Housing (205) is further coupled to first end cap (210) by a first coupling member (315) and a second coupling member (320) and is also coupled to an opposite second end cap (215) by a third coupling member (320) and a fourth coupling member (325). Interface sealing members (330a, 330b, 330c, 330d) seal between housing (205) and first end cap (210). Interface sealing members (335a, 335b, 335c, 335d) seal between housing (205) and second end cap (215).

Abstract: An apparatus and method for sensor architecture based on bulk machining of Silicon-On-Oxide wafers and fusion bonding that provides a symmetric, nearly all-silicon, hermetically sealed MEMS device having a sensor mechanism formed in an active semiconductor layer, and opposing silicon cover plates each having active layers bonded to opposite faces of the sensor mechanism. The mechanism is structured with sensor mechanical features structurally supported by at least one mechanism anchor. The active layers of the cover plates each include interior features structured to cooperate with the sensor mechanical features and an anchor structured to cooperate with the mechanism anchor. A handle layer of each cover plate includes a pit extending there through in alignment with the cover plate anchor. An unbroken rim of dielectric material forms a seal between the cover plate anchor and the pit and exposes an external surface of the cover plate anchor.

Abstract: Microelectromechanical system (MEMS) integrated micro devices and acceleration sensor devices formed of first and second silicon wafers that are permanently joined together in a composite silicon wafer having an array of first complete stand-alone three-dimensional micromechanical device features formed in the first silicon wafer, an array of second complete stand-alone three-dimensional micromechanical device features formed in the second silicon wafer, and one or more composite three-dimensional micromechanical device features formed of first partial three-dimensional micromechanical device features formed in the first silicon wafer that are permanently joined to cooperating second partial three-dimensional micromechanical device features formed in the second silicon wafer.

Abstract: A method for fabrication of microelectromechanical systems (MEMS) integrated micro devices and acceleration sensor devices formed according to the method, the method being micromachining an array of first three-dimensional micromechanical device features in a first silicon wafer; micromachining an array of second three-dimensional micromechanical device features in a second silicon wafer, wherein the second three-dimensional micromechanical device features are configured to cooperate with the first three-dimensional micromechanical device features when joined therewith; mutually aligning the first and second arrays of device features by aligning the first and second wafers; permanently joining the first and second arrays of device features into an array of integrated micro devices as a function of permanently joining the first and second wafers into a single composite wafer; and subsequently separating the array of integral devices into individual devices each having a set of the first and second device featu

Abstract: Microelectromechanical system (MEMS) integrated micro devices and acceleration sensor devices formed of first and second silicon wafers that are permanently joined together in a composite silicon wafer having an array of first complete stand-alone three-dimensional micromechanical device features formed in the first silicon wafer, an array of second complete stand-alone three-dimensional micromechanical device features formed in the second silicon wafer, and one or more composite three-dimensional micromechanical device features formed of first partial three-dimensional micromechanical device features formed in the first silicon wafer that are permanently joined to cooperating second partial three-dimensional micromechanical device features formed in the second silicon wafer.

Abstract: A method for fabrication of microelectromechanical systems (MEMS) integrated micro devices and acceleration sensor devices formed according to the method, the method being micromachining an array of first three-dimensional micromechanical device features in a first silicon wafer; micromachining an array of second three-dimensional micromechanical device features in a second silicon wafer, wherein the second three-dimensional micromechanical device features are configured to cooperate with the first three-dimensional micromechanical device features when joined therewith; mutually aligning the first and second arrays of device features by aligning the first and second wafers; permanently joining the first and second arrays of device features into an array of integrated micro devices as a function of permanently joining the first and second wafers into a single composite wafer; and subsequently separating the array of integral devices into individual devices each having a set of the first and second device featu

Abstract: Disclosed is an accelerometer for measuring seismic data. The accelerometer includes a proof mass that is resiliently coupled to a support structure by folded beams, S-shaped balanced beams, straight beams, and/or folded beams with resonance damping. The support structure further includes travel stops for limiting transverse motion of the proof mass.

Abstract: Disclosed is an accelerometer for measuring seismic data. The accelerometer includes a proof mass that is resiliently coupled to a support structure by folded beams, S-shaped balanced beams, straight beams, and/or folded beams with resonance damping. The support structure further includes travel stops for limiting transverse motion of the proof mass.

Abstract: A merged-mask micro-machining process is provided that includes the application of a plurality of layers of masking material that are patterned to provide a plurality of etching masks.

Abstract: Disclosed is an accelerometer for measuring seismic data. The accelerometer includes a proof mass that is resiliently coupled to a support structure by folded beams, S-shaped balanced beams, straight beams, and/or folded beams with resonance damping. The support structure further includes travel stops for limiting transverse motion of the proof mass.