Abstract: Multi-layered, planar microshells having low stress for encapsulation of devices such as MEMS and microelectronics. The microshells may include a perforated pre-sealing layer, below which a sacrificial layer is accessed, and a sealing layer to close the perforation in the pre-sealing layer after the sacrificial material is removed. The sealing layer may further include a nonhermetic layer to physically occlude the perforation and a hermetic layer over the nonhermetic occluding layer to seal the perforation. The various layers may be formed employing processes having opposing stresses to tune the residual stress of the multi-layered microshell. In an embodiment, the hermetic layer is a metal which is deposited with a process tuned to impart a tensile stress to lower the residual stress in the microshell below the magnitude of cumulative stress present in sealing layer and pre-sealing layer.

Abstract: A MEMS structure having a compensated resonating member is described. In an embodiment, a MEMS structure comprises a resonating member coupled to a substrate by an anchor. A dynamic mass-load is coupled with the resonating member. The dynamic mass-load is provided for compensating a change in frequency of the resonating member by altering the moment of inertia of the resonating member by way of a positional change relative to the anchor.

Abstract: An electrostatic transducer for micromechanical resonators, in which the electrode gaps are filled with a dielectric material having a much higher permittivity than air. This internal electrostatic transducer has several advantages over both air-gap electrostatic and piezoelectric transduction; including lower motional impedance, compatibility with advanced scaled CMOS device technology, and extended dynamic range. In one aspect, in order to minimize energy losses, the dielectric material has an acoustic velocity which is matched to that of the resonator material. Internal electrostatic transduction can be adapted to excite and detect either vertical modes (perpendicular to the substrate) or lateral modes (in the plane of the substrate). Its increased transduction efficiency is of particular importance for reducing the motional resistance of the latter.

Abstract: A MEMS structure having a temperature-compensated resonating member is described. The MEMS structure comprises a stress inverter member coupled with a substrate. A resonating member is housed in the stress inverter member and is suspended above the substrate. The MEMS stress inverter member is used to alter the thermal coefficient of frequency of the resonating member by inducing a stress on the resonating member in response to a change in temperature.

Abstract: In fabricating a microelectromechanical structure (MEMS), a method of forming a narrow gap in the MEMS includes a) depositing a layer of sacrificial material on the surface of a supporting substrate, b) photoresist masking and at least partially etching the sacrificial material to form at least one blade of sacrificial material, c) depositing a structural layer over the sacrificial layer, and d) removing the sacrificial layer including the blade of the sacrificial material with a narrow gap remaining in the structural layer where the blade of sacrificial material was removed.

Abstract: Disclosed is an oscillator that relies on redundancy of similar resonators integrated on chip in order to fulfill the requirement of one single quartz resonator. The immediate benefit of that approach compared to quartz technology is the monolithic integration of the reference signal function, implying smaller devices as well as cost and power savings.

Abstract: A method of etching silicon carbide using a nonmetallic mask layer. The method includes providing a silicon carbide substrate; forming a non-metallic mask layer by applying a layer of material on the substrate; patterning the mask layer to expose underlying areas of the substrate; and etching the underlying areas of the substrate with a plasma at a first rate, while etching the mask layer at a rate lower than the first rate.

Abstract: A micro-machined angle measurement gyroscope. In one implementation, the gyroscope includes a substrate; a proof mass coupled to the substrate by an isotropic suspension such that the proof mass can move in any direction in the plane of the substrate; a plurality of drive electrodes configured to cause the proof mass to oscillate in the plane of the substrate; and a plurality of sense electrodes configured to sense the motion of the proof mass in the plane of the substrate. In another implementation, the gyroscope includes a substrate; a proof mass suspended above the substrate by an isotropic suspension such that the proof mass can move in any direction in an oscillation plane normal to the substrate; a plurality of drive electrodes configured to cause the proof mass to oscillate in the oscillation plane; and a plurality of sense electrodes configured to sense the motion of the proof mass in the oscillation plane.

Abstract: A method of fabricating a microfabricated filter. The method includes forming a frame structure and forming a plurality of openings through the frame structure. A permeable polysilicon membrane is formed over the plurality of openings through the frame structure. At least part of the sacrificial structure is etched with an etchant wherein the etchant passes through the permeable polysilicon membrane. The permeable polycrystal silicon membrane may have a thickness of between about 0.05 micrometers and about 0.30 micrometers.

Abstract: This invention relates to micro-electromechanical systems using silicon-germanium films. Such a system includes one or more layers of Si1−xGex, deposited on a substrate, where 0<x≦1. One or more transistors can be formed on the substrate.

Abstract: A microfabricated gyroscope to measure rotation about an axis parallel to the surface of the substrate. A voltage differential may be applied between pairs of electrode fingers to reduce the quadrature error. A microfabricated gyroscope includes a vibratory structure and interdigited electrodes having a high aspect ratio.

Abstract: A microfabricated gyroscopic sensor for measuring rotation about a Z-axis. The sensor includes a substrate, a first mass, a second mass, a coupling system connecting the first mass and the second mass, and a suspension system connecting the first mass and the second mass to the substrate. The sensor further includes a drive system to cause the first mass and the second mass to vibrate in an antiphase mode along a drive axis, and a position sensor to measure a displacement of the first mass and the second mass along a sense axis perpendicular to the drive axis and generally parallel to the surface of the substrate, wherein rotation of the first mass and the second mass about the Z-axis perpendicular to the surface of the substrate and vibration of the first mass and the second mass along the drive axis generates a Coriolis force to vibrate the first mass and the second mass along the sense axis in antiphase to each other.

Abstract: A Q-controlled microresonator and devices including such resonators.

Abstract: This invention relates to micro-electromechanical systems using silicon-germanium films.

Abstract: Break-away tethers to secure electronic, mechanical, optical, or other microstructures, during release from one substrate and transfer to another. Microstructures are fabricated with integrated tethers attaching them to a first substrate. The structures are undercut by etching and contacted and bonded to a second substrate. First and second substrates are separated, breaking the tethers.

Abstract: A method of fabricating a micromachine includes the step of constructing a low surface energy film on the micromachine. The micromachine is then rinsed with a rinse liquid that has a high surface energy, relative to the low surface energy film, to produce a contact angle of greater than 90.degree. between the low surface energy film and the rinse liquid. This relatively large contact angle causes any rinse liquid on the micromachine to be displaced from the micromachine when the micromachine is removed from the rinse liquid. In other words, the micromachine is dried by dewetting from a liquid-based process. Thus, a separate evaporative drying step is not required, as the micromachine is removed from the liquid-based process in a dry state. The relatively large contact angle also operates to prevent attractive capillary forces between micromachine components, thereby preventing contact and adhesion between adjacent microstructure surfaces.

Abstract: A microfabricated gyroscope to measure rotation about an axis parallel to the surface of the substrate. A voltage differential may be applied between pairs of electrode fingers to reduce the quadrature error. A microfabricated gyroscope includes a vibratory structure and interdigited electrodes having a high aspect ratio.

Abstract: An accelerometer comprises a proof mass, a first resonant tuning fork connected to the proof mass, a second resonant tuning fork connected to the proof mass, and a flexural lever leverage system supporting the proof mass above a substrate. The flexural lever leverage system enhances an acceleration force applied to the proof mass to cause a tensile force in the first resonant tuning fork which raises its resonant frequency, and a compressive force in the second resonant tuning fork which lowers its resonant frequency. The device may be fabricated using semiconductor-based surface-micromachining technology.

Abstract: A Q-controlled microresonator and devices including such resonators.

Abstract: A micromachined force sensor containing separate sensing and actuator structures. A member is suspended above the substrate so that it is movable along an axis in response to a force. The member includes a set of parallel sense fingers and a separate set of parallel force fingers. The sense fingers are positioned between fingers of two sense plates, to form a first differential capacitor, whose capacitance changes when the member moves in response to a force along the axis. The change in capacitance induces a sense signal on the member, which permits the measurement of the magnitude and duration of the force. The force fingers are positioned between fingers of two actuator plates, to form a second differential capacitor. The sense signal can be used to provide feedback to the second differential capacitor to generate different electrostatic forces between the force fingers and the two actuator plates, to offset the force applied along the preferred axis.