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Simple piezoresistive pressure sensor. Simple piezoresistive accelerometer.

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Presentation on theme: "Simple piezoresistive pressure sensor. Simple piezoresistive accelerometer."— Presentation transcript:

1 Simple piezoresistive pressure sensor

2 Simple piezoresistive accelerometer

3 Simple capacitive accelerometer Cap wafer may be micromachined silicon, pyrex, … Serves as over-range protection, and damping Typically would have a bottom cap as well. C(x)=C(x(a)) Cap wafer

4 Simple capacitive pressure sensor C(x)=C(x(P))

5 ADXL50 Accelerometer +-50g Polysilicon MEMS & BiCMOS 3x3mm die Integration of electronics!

6 ADXL50 Sensing Mechanism Balanced differential capacitor output Under acceleration, capacitor plates move changing capacitance and hence output voltage On-chip feedback circuit drives on-chip force-feedback to re- center capacitor plates (improved linearity).

7 Analog Devices Polysilicon MEMS

8 ADXL50 – block diagram

9 Sense Circuit Electrostatic Drive Circuit Proof Mass Digital Output MEMS Gyroscope Chip Rotation induces Coriolis acceleration J. Seeger, X. Jiang, and B. Boser halteres

10 MEMS Gyroscope Chip 1  m Drive 0.01 Å Sense J. Seeger, X. Jiang, and B. Boser

11 Two-Axis Gyro, IMI(Integrated Micro Instruments Inc.)/ADI (fab)

12 Single chip six-degree-of-freedom inertial measurement unit (uIMU) designed by IMI principals and fabricated by Sandia National Laboratories

13 TI Digital Micromirror Device



16 NEU/ADI/Radant/MAT Microswitches SEM of NEU microswitch Drain Source Gate Beam Drain Gate Source Beam Drain Gate Source Surface Micromachined Post-Process Integration with CMOS 20-100 V Electrostatic Actuation ~100 Micron Size MAT Microswitch

17 Contact End of Switch Contact Detail

18 Packaged Plasma Source Top View Side View Die in Hybrid Package

19 Fabrication SEM of Interdigitated Capacitor Structure

20 12/19/2014 Spectrometer cross-section Surface Micromachined Spring System Electrostatic Actuator Plates

21 12/19/2014 Fabricated Microspectrometers

22 Intensity vs. Wavelength =515 nm =515 nm FWHM = 25nm RP = 21  = 575nm FWHM = 30nm RP = 20 =625nm =625nm FWHM = 39nm RP = 16

23 Figure 1. Qualcomm Mirasol Display IMOD Structure Showing Light Reflecting off the Thin-film Stack and Mirror Interfering to Produce Color.

24 Optical MEMS Vibration Sensors Uniform cantilever beamFoster Miller - Diaphragm Cantilevered paddleCantilevered supported diaphragm

25 Optically interrogated MEMS sensors 55  m length cantilevered paddle after 7 hours of B.O.E. releasing and lifted up with a 1  m probe (~0.35  m thick, 2  m gap)

26 Courtesy Connie Chang-Hasnain


28 Micromachining Ink Jet Nozzles Microtechnology group, TU Berlin

29 Microfluidic Chips

30 (UCLA, Fan)

31 (Gruning)

32 Gene chips, proteomics arrays.

33 NEMS: TOWARD PHONON COUNTING: Quantum Limit of Heat Flow. Roukes Group Cal Tech Tito

34 From Ashcroft and Mermin, Solid State Physics.

35 Other: NSF-Funded NSEC, Center for High-Rate Nanomanufacturing (CHN): High-rate Directed Self-Assembly of Nanoelements Nanotemplate:  Layer of assembled nanostructures transferred to a wafer. Template is intended to be used for thousands of wafers. Nanotube Memory Device Partner: Nantero first to make memory devices using nanotubes Properties: n onvolatile, high speed at 10 15 cycles), resistant to heat, cold, magnetism, vibration, and cosmic radiation. Proof of Concept Testbed

36 Switch Logic, 1996, Zavracky, Northeastern InverterNOR Gate

37 Simple Carbon Nanotube Switch Diameter: 1.2 nm Elastic Modulus: 1 TPa Electrostatic Gap: 2 nm Binding Energy to Substrate: 8.7x10 -20 J/nm Length at which adhesion = restoring force: 16 nm Actuation Voltage at 16 nm = 2 V Resonant frequency at 16 nm = 25 GHz Electric Field = 10 9 V/m or 10 7 V/cm + Geom. (F-N tunneling at > 10 7 V/cm) Stored Mechanical Energy (1/2 k x 2 ) = 4 x 10 -19 J = 2.5 eV 4 x 10 -19 = ½ CV 2 gives C = 2 x 10 -19 F << electrode capacitance! Much more energy stored in local electrodes than switch.

38 NEMS Switch Fabrication: To be discussed. (a) Silicon chip with 500 nm of thermally grown oxide, 20 nm of tungsten, and PMMA. (b) Electron beam lithography was used to define features in the PMMA layer. An ICP etch was used to pattern the tungsten and etch down into the oxide. (c) A Cr/Au layer was evaporated and lifted off by removing the tungsten. (d) DEP was performed to assemble a small bundle of nanotubes traversing the trench between the two side electrodes.

39 NEMS Switch Operation (a) Scanning electron micrograph of a switch. Atomic force microscopy scans before (b) and after (c) switch actuation. (d) Initial (solid lines), second (dashed lines), and third (dotted lines) I-V sweeps for the device seen in (a-c). This device had a vertical gap of 24 nm and a trench width of 195 nm.

40 NEMS Switch Problems During Operation

41 NEMS Switch Electro-Mechanical Model

42 Carbon Nanotube for Adhesion Measurement

43 Biological Nanomotor

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