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We present a MEMS-based differential scanning calorimetric (DSC) device combining highly sensitive thermoelectric sensing, on-chip self-calibration, and microfluidic regulation for thermodynamic characterization of biomolecular samples on a minimized scale. The device integrates well-defined microfluidic reaction chambers and utilizes a three-dimensional structure in which a layer of resistive microheaters...
This paper handles a single approach to solve two major reliability issues of the previously proposed micro shutter using roll actuators. Material and structural change from Al/SiNx to Mo/Mo improves the temperature stability of an aperture size by matching CTEs of bi-layer ideally. It is also effective to extend the rated lifetime of the shutter by eliminating a dielectric charging layer, SiNx. The...
This paper demonstrates a dual-mode (DM) oscillator which simultaneously excites the fundamental and third-order modes of a micromachined, piezo-on-silicon bulk acoustic wave (BAW) resonator for real-time self-temperature measurement. By concurrently measuring the temperature coefficient of frequency (TCF) at 30 MHz (f1) and 87 MHz (f3), a beat frequency (fb) with TCF of 162 ppm/°C is extracted. Phase...
This paper discusses the design and realization of a micromachined micro Coriolis flow sensor with integrated electrodes for both electrostatic actuation and capacitive readout. The sensor was realized using semicircular channels just beneath the surface of the silicon wafer. The channels have thin silicon nitride walls to minimize the channel mass with respect to the mass of the moving fluid. A comb-shaped...
We present the design, fabrication, and measurement of an RF MEMS switched capacitor with >; 10 W power handling at 10 GHz under hot-switching conditions while maintaining a relatively-low (<; 30 V) pull-in voltage. The device consists of separate RF and DC electrodes, which are defined underneath a temperature-stable circular beam, to result in a large spring constant above the RF electrode...
This paper reports the design, modeling and characterization of a 2-DoF twisting electrothermal (ET) actuator for reducing parasitic motion in the application of an SOI-CMOS-MEMS-based Scanning Laser Rangefinder (SLR). A schematic-based model was built using a hierarchical MEMS behavioral model library (NODAS) to develop the concept of independently actuating two parallel metal-polysilicon-oxide CMOS-MEMS...
This paper reports on the fabrication and characterization of MEMS-scale devices from a mechanically dynamic polymer nanocomposite, consisting of a cotton-derived cellulose nanofibers encased in a poly(vinyl acetate) matrix, with a stiffness modulated by the presence or absence of water. Microtensile testing showed that the Young's modulus (E) of the nanocomposite is initially ~2.7 GPa, but reduces...
We present an attractive poly-SiGe thin film packaging and MEM (Micro Electro-Mechanical) platform technology for integrating various packaged MEM devices above standard CMOS. The packages, having cavities as large as 1 mm2, make use of pillars designed to withstand subsequent molding during 1st level packaging. Covers on top of the release holes avoid deposition inside the cavity during sealing....
In this work we describe the manufacturing and characterization of patterned surfaces with large spatial contrast in wettability. We find drastic enhancement of pool boiling performance in water. In comparison to a hydrophilic SiO2 surface with a wetting angle of 7°, surfaces combining superhydrophilic and superhydrophobic patterns can quadruple the heat transfer coefficient (HTC). Superhydrophilic...
In this paper, an alternative test method for MEMS convective accelerometers is presented. It is first demonstrated that device sensitivity can be determined without the use of physical test stimuli by simple electrical measurements. Using a previously developed behavioral model that allows efficient Monte-Carlo simulations, we have established a good correlation between electrical test parameters...
This work presents temperature compensated single-device fully micromechanical (circuit-less) oscillators. Thermal-piezoresistive interactions in certain micromechanical resonant structures can lead to self-sustained mechanical vibrations. Self-sustained single crystalline silicon oscillators with frequencies in the few MHz range have been fabricated and their temperature drift behavior is characterized...
This paper reports an electrostatically actuated ohmic contact micro-relay for high power RF applications. Stainless steel cantilevered micro-relays with platinum-rhodium contacts are micromachined from bulk foils and assembled on the printed circuit boards. Micromachined aluminum heat sinks are integrated on the cantilevers above the point of contact. The devices have a footprint of 2×3.2 mm2. Fabricated...
This paper presents the high-level of stability of voltage references operated in alternating current (AC) and based on the pull-in effect in split-fingers MEMS architectures. Our work deals with the design and fabrication of new MEMS devices and presents results of both electrical and mechanical characterizations as well as the development of an optimized read-out electronics showing a mature stage...
This paper reports the performance of a wireless MEMS bimorph temperature sensor integrated on a bearing for component health monitoring applications. The sensor consists of a robust array of bimorphs consisting of gold and thermally-grown oxide operable to at least 300°C. Fabrication details are included, as well as the hermetic packaging information. Speed of actuation results from a high-speed...
We report a SiC MEMS microhotplate designed for high temperature characterization of nanomaterials in transmission electron microscopes (TEMs). The microhotplate integrates, for the first time, a microheater of doped polycrystalline silicon carbide (poly-SiC) and electron-transparent windows of amorphous SiC (a-SiCx) on a freestanding membrane of undoped poly-SiC. Our work focuses on the development...
This paper reports on a continuously tunable MEMS capacitor with a wide tuning range of 5:1, high quality factor of better than 100 (at 1 GHz) at each tuned state, and self-resonance frequency of more than 13.5 GHz. The temperature stability of the capacitance in the temperature range of -50°C to 60°C is better than 7%, which is one of the best reported for continuously tuned capacitors. The maximum...
Micro-heat pipes incorporating advanced wicks are promising for the thermal management of high power density semiconductor and MEMS devices. We report experimental characterization of the heat transfer performance of wicks consisting of dense arrays of superhydrophilic Cu micropost wicks fabricated using electrochemical deposition and controlled chemical oxidation. A very high heat removal capability...
Aim of the research work is to determine the influence of thermo-mechanical stress on different assembly variants on the reliability of the micromechatronic system by thermo-mechanical stress analysis with combined simulation of the assembly. Therefore, four different assemblies are examined each on four different substrates, two substrate materials for MID and two flexible substrates. The frame of...
Time-dependent thermoelectromechanical behavior of metal contacts in microelectromechanical system (MEMS) devices and packaging is studied. The analysis relates the electrical constriction resistance to contact temperature and contact surface evolution over time, using a microcontact asperity creep model for metal microcontacts under continual applied or residual stresses. The effects of contact temperature...
This paper presents a zero-level packaging technology for hermetic encapsulation of MEMS. The technology relies on the “chip capping” of the MEMS using a metallic bond made by means of diffusion soldering of a Cu-Sn system at a temperature of around 250°C. For this, on a “capping wafer” a sealing ring (or bond frame), composed of a double layer of Cu/Sn, is grown, and on the MEMS wafer a matching...
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