Abstract: A microelectromechanical microphone and method of manufacturing the same are disclosed. The microphone has a moveable diaphragm and a fixed backplate that create a variable capacitance. A fixed anchor electrically coupled to the diaphragm has an electrode that measures the variable capacitance, but also measures an unwanted, additive, parasitic capacitance. Various embodiments include a reference electrode, manufactured in the same deposition layer as the diaphragm or anchor, that measures only the parasitic capacitance. A circuit is provided either on-chip or off-chip that subtracts the capacitance measured at the reference electrode from that measured at the anchor, thereby producing only the desired variable capacitance as output. Because the reference electrode is deposited at the same time as the diaphragm or anchor, only minimal changes are required to existing manufacturing techniques.

Abstract: A microchip has a base die with a conductive interconnect and an isolation trench around at least a portion of the conductive interconnect, and a cap die secured to the base die. A seal, formed from a metal material, is positioned between the base die and the cap die to secure them together. The microchip also has a blocking apparatus, between the isolation trench and the metal seal, that at least in part prevents the metal material from contacting the interconnect.

Abstract: A microchip has a base die with a conductive interconnect and an isolation trench around at least a portion of the conductive interconnect, and a cap die secured to the base die. A seal, formed from a metal material, is positioned between the base die and the cap die to secure them together. The microchip also has a blocking apparatus, between the isolation trench and the metal seal, that at least in part prevents the metal material from contacting the interconnect.

Abstract: A microphone system has two diaphragms and are mechanically interconnected such that they respond in antiphase to an acoustic signal impinging on one of the diaphragms. The two diaphragms produce two variable capacitances that vary proportionately but inversely to one another. Voltage signals produced by the two variable capacitances are summed to provide an output signal proportional to the acoustic signal, but with greater sensitivity than a single-diaphragm microphone.

Abstract: A dual backplate MEMS microphone system includes a flexible diaphragm sandwiched between two single-crystal silicon backplates. Such a MEMS microphone system may be formed by fabricating each backplate in a separate wafer, and then transferring one backplate from its wafer to the other wafer, to form two separate capacitors with the diaphragm.

Abstract: A microelectromechanical microphone and method of manufacturing the same are disclosed. The microphone has a moveable diaphragm and a fixed backplate that create a variable capacitance. A fixed anchor electrically coupled to the diaphragm has an electrode that measures the variable capacitance, but also measures an unwanted, additive, parasitic capacitance. Various embodiments include a reference electrode, manufactured in the same deposition layer as the diaphragm or anchor, that measures only the parasitic capacitance. A circuit is provided either on-chip or off-chip that subtracts the capacitance measured at the reference electrode from that measured at the anchor, thereby producing only the desired variable capacitance as output. Because the reference electrode is deposited at the same time as the diaphragm or anchor, only minimal changes are required to existing manufacturing techniques.

Abstract: A method for producing a MEMS device having improved charge elimination characteristics includes providing a substrate having one or more layers, and applying a first charge elimination layer onto at least one portion of one given layer of the substrate. The method may then (1) apply a sacrificial layer onto the first charge elimination layer, (2) apply a second charge elimination layer onto at least a portion of the sacrificial layer, and (3) deposit a movable layer onto at least a portion of the second charge elimination layer. To form a structure within the movable layer the method may etch the movable layer. The method may then etch the sacrificial layer to release the structure.

Abstract: A bulk acoustic wave gyroscope has a primary member in a member plane, and an electrode layer in an electrode plane spaced from the member plane. The electrode layer has a first portion that is electrically isolated from a second portion. The first portion, however, is mechanically coupled with the second portion and faces the primary member (e.g., to actuate or sense movement of the primary member). For support, the second portion of the electrode is directly coupled with structure in the member plane.

Abstract: A capped micromachined accelerometer with a Q-factor of less than 2.0 is fabricated without encapsulating a high-viscosity gas with the movable mass of the micromachined accelerometer by providing small gaps between the movable mass and the substrate, and between the movable mass and the cap. The cap may be an silicon cap, and may be an ASIC smart cap.

Abstract: A dual backplate MEMS microphone system including a flexible diaphragm sandwiched between two single-crystal silicon backplates may be formed by fabricating each backplate in a separate wafer, and then transferring one backplate from its wafer to the other wafer, to form two separate capacitors with the diaphragm.

Abstract: A method for measuring retained surface charges within a MEMS device includes performing an initial voltage sweep on the MEMS device, and recording the capacitance between a first and second electrode of the MEMS device. The method may then (1) apply a stress signal to the MEMS device that causes a first and/or second electrode within the MES device to retain a surface charge, and (2) perform at least one additional voltage sweep on the MEMS device. The method may record the capacitance during the additional voltage sweep(s), and calculate a C-V center voltage shift based upon the data obtained during the initial voltage sweep and additional voltage sweep. The voltage shift is representative of the retained surface charge.

Abstract: A MEMS device has a first member that is movable relative to a second member. At least one of the first member and the second member has exposed silicon carbide with a water contact angle of greater than about 70 degrees.

Abstract: A micromachining process forms a plurality of layers on a wafer. This plurality of layers includes both a support layer and a given layer. The process also forms a mask, with a mask hole, at least in part on the support layer. In this configuration, the support layer is positioned between the mask hole and the given layer, and longitudinally spaces the mask hole from the given layer. The process also etches a feature into the given layer through the mask hole.

Abstract: A micromachining process forms a plurality of layers on a wafer. This plurality of layers includes both a support layer and a given layer. The process also forms a mask, with a mask hole, at least in part on the support layer. In this configuration, the support layer is positioned between the mask hole and the given layer, and longitudinally spaces the mask hole from the given layer. The process also etches a feature into the given layer through the mask hole.

Abstract: A MEMS stiction testing method applies a first electrical signal to a MEMS device having two opposing surfaces to cause the two opposing surfaces to make physical contact. The two opposing surfaces produce a second electrical signal when in physical contact. The method then substantially mitigates the first electrical signal after detecting that the second electrical signal has reached a prescribed maximum value.

Abstract: A bulk acoustic wave gyroscope has a primary member in a member plane, and an electrode layer in an electrode plane spaced from the member plane. The electrode layer has a first portion that is electrically isolated from a second portion. The first portion, however, is mechanically coupled with the second portion and faces the primary member (e.g., to actuate or sense movement of the primary member). For support, the second portion of the electrode is directly coupled with structure in the member plane.

Abstract: A dual backplate MEMS microphone system includes a flexible diaphragm sandwiched between two single-crystal silicon backplates. Such a MEMS microphone system may be formed by fabricating each backplate in a separate wafer, and then transferring one backplate from its wafer to the other wafer, to form two separate capacitors with the diaphragm.

Abstract: A MEMS device has a first member that is movable relative to a second member. At least one of the first member and the second member has exposed silicon carbide with a water contact angle of greater than about 70 degrees.

Abstract: A nickel-based material is used on one or both wafers to be bonded, and the two wafers are bonded at low temperature and pressure through interdiffusion of the nickel-based material with either another nickel-based material or aluminum. In various embodiments, nickel-based walls are formed on one wafer, and corresponding walls are formed on the other wafer from a nickel-based material or aluminum. The walls of the two wafers are placed in contact with one another under sufficient pressure and temperature to cause bonding of the walls through interdiffusion.

Abstract: A MEMS stiction testing method applies a first electrical signal to a MEMS device having two opposing surfaces to cause the two opposing surfaces to make physical contact. The two opposing surfaces produce a second electrical signal when in physical contact. The method then substantially mitigates the first electrical signal after detecting that the second electrical signal has reached a prescribed maximum value.