Simple piezoresistive pressure
sensor
Simple piezoresistive accelerometer
Simple capacitive accelerometer
C(x)=C(x(a))
Cap wafer
• Cap wafer may be micromachined silicon, pyrex,
…
• Serves as over-range protection, and damping
• Typically would have a bottom cap as well.
Simple capacitive pressure sensor
C(x)=C(x(P))
ADXL50 Accelerometer
• +-50g
• Polysilicon
MEMS &
BiCMOS
• 3x3mm die
• Integration of
electronics!
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 recenter capacitor plates (improved linearity).
Analog Devices Polysilicon
MEMS
ADXL50 – block diagram
•
http://www.analog.com/en/mems-and-sensors/imems-accelerometers/products/index.html
MEMS Gyroscope Chip
Rotation
induces
Coriolis
acceleration
Proof
Mass
Sense
Circuit
Electrostatic
Drive Circuit
halteres
J. Seeger, X. Jiang, and B. Boser
Digital
Output
MEMS Gyroscope Chip
J. Seeger, X. Jiang, and B. Boser
Two-Axis Gyro, IMI(Integrated Micro Instruments Inc.)/ADI (fab)
Single chip six-degree-of-freedom inertial
measurement unit (uIMU) designed by IMI
principals and fabricated by Sandia National Laboratories
TI Digital Micromirror Device
www.dlp.com
NEU/ADI/Radant/MAT Microswitches
http://www.radantmems.com/radantmems/switchoperation.html
Surface Micromachined
Post-Process Integration with CMOS
20-100 V Electrostatic Actuation
~100 Micron Size
Gate
Drain
Beam
Source
Beam
Drain
Gate
Source
Gate
SEM of NEU microswitch
Landing
ring
Drain
Source
MEMS
Seal
ring
Microbump
Feedthrough
Dielectric
Package Substrate
MAT Microswitch
Contact End of Switch
Contact Detail
Packaged Plasma Source
Top View
Die in Hybrid Package
Side View
Fabrication
PR
Cr/Au/TiW
Glass Wafer
Expose/Dev.
TiW etch
Electroplate
Gold
PR strip
TiW/Au/Cr etch
spiral coil
Bond to 10 mm diam.
glass chamber
interdigitated capacitor
to vacuum system
SEM of Interdigitated
Capacitor Structure
Spectrometer cross-section
Surface Micromachined
Spring System
Electrostatic
Actuator Plates
4/8/2015
Fabricated Microspectrometers
4/8/2015
Intensity vs. Wavelength
1.2
l =515 nm
l = 575nm
FWHM = 25nm
FWHM = 30nm
l =625nm
RP = 21
RP = 20
FWHM = 39nm
RP = 16
Intensity (arb. units)
1
0.8
0.6
0.4
0.2
0
450
500
550
600
Wavelength (nm)
650
700
750
Figure 1. Qualcomm Mirasol Display IMOD
Structure Showing Light Reflecting off the
Thin-film Stack and Mirror Interfering to
Produce Color.
Optical MEMS Vibration Sensors
Uniform cantilever beam
Cantilevered paddle
Foster Miller - Diaphragm
Cantilevered supported diaphragm
Optically interrogated MEMS sensors
55 mm length cantilevered paddle after 7
hours of B.O.E. releasing and lifted up with
a 1mm probe (~0.35mm thick, 2mm gap)
Courtesy Connie Chang-Hasnain
Courtesy Connie Chang-Hasnain
Micromachining Ink Jet Nozzles
Microtechnology group, TU Berlin
Microfluidic Chips
(UCLA, Fan)
(Gruning)
Gene chips, proteomics arrays.
NEMS: TOWARD PHONON COUNTING: Quantum Limit of Heat Flow.
Roukes
Group
Cal Tech
Tito
From Ashcroft and
Mermin, Solid
State Physics.
Other: NSF-Funded NSEC, Center for High-Rate
Nanomanufacturing (CHN): High-rate Directed Self-Assembly of
Nanoelements
Proof of Concept Testbed
Nanotube Memory Device
Nanotemplate:
 Layer of assembled
nanostructures transferred to
a wafer. Template is intended
to be used for thousands of
wafers.
Partner: Nantero
first to make memory devices using
nanotubes
Properties: nonvolatile, high speed
at <3ns, lifetime (>1015 cycles),
resistant to heat, cold, magnetism,
vibration, and cosmic radiation.
Switch Logic, 1996, Zavracky, Northeastern
Inverter
NOR Gate
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 = 109 V/m or 107 V/cm + Geom.
(F-N tunneling at > 107 V/cm)
Stored Mechanical Energy (1/2 k x2 ) = 4 x 10-19 J = 2.5 eV
4 x 10-19 = ½ CV2 gives C = 2 x 10-19 F << electrode capacitance!
Much more energy stored in local electrodes than switch.
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.
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.
NEMS
Switch
Problems
During
Operation
NEMS Switch Electro-Mechanical Model
Carbon Nanotube for Adhesion Measurement
Biological Nanomotor