Tài liệu MEMS Sensors for Biomedical Applications pptx

MEMS Sensors for Biomedical
Applications
Yu-Chong Tai
Professor of EE
Member of NSF/CNSE
California Institute of Technology
(NSF/ERC Industry Day, May 16-17, 2001)
What is MEMS?
• In US: Microdynamics
• In Europe: Micro Systems (Technology)
• In Japan: Micromachines, MicroRobots
A Micro-Electro-Mechanical System (MEMS) is a batch-fabricated
(microfabricated) system that contains both electrical and mechanical
components with characteristic sizes ranging
from nanometers to millimeters.
Other Names
Machine Size
nm
µm
mm m
km
Conventional
Machines
Micromachines
(MEMS)
Molecular (Nano)
Machines
Quantity
Pressure Sensors
Nitride diaphragm Poly strain gauges
200 µm

Schlumberger Oil-Well Pressure Sensor
•10,000 ± 2 psi design
•Multi-diaphragm configuration
4 nitride
Diaphragms
Polysilicon
thermistor
0.45
0.5
0.55
0.6
0.65
0 1000 2000 3000 4000 5000
Pressure (psi)
output voltage (V)
MEMS Pressure Sensor Probe
for Intraocular Pressure Measurement
Pressure sensor
Sensor Tip
Flexible ribbon
Wafer with flexible
pressure sensor skins
Vacuum-Insulated Shear Stress Sensor
Cross-section
Photograph
Polysilicon Wire
(3 x 150 x 0.5 µm
3
)
Vacuum Cavity

(200 x 200 x 2 µm
3
)
Polysilicon wire
Nitride diaphragm
Vacuum cavity
Si substrate
Metal lead Metal lead
Successful Test on NASAF 15
2.86 cm
1 cm
Micro
Sensor
Stanton
Sensor
M=0.3
M=0.5
M=0.7
M=0.9
Time
Shear Stress (Pa)
Shear-stress Sensor Imager
2 cm
2 mm
1 mm
Pressure
sensor
Temperature
sensor
Shear stress

sensor
200 µm
Multi-sensor chip:
Pressure, Temperature and Flow
Five sensor clusters with a
pitch of 2 mm.
1 cm
MEMS Mass Flow Meter
PCB
Inlet
N
2
Bonding wires
Multi-sensor array chip
Channel chip
Schematic of packaged device
picture of a packaged device
Channel width: 2.5 mm
Channel height: 0.2 mm
Channel length: 18 mm
5.0
5.5
6.0
6.5
0.0 0.5 1.0 1.5
Q
1/2.2
P (mW)
5.0
5.5

6.0
6.5
7.0
7.5
012345678910
Q (SLPM)
Laminar
flow
Turbulent flow
Power (mW)
Calibration of the thermal flowmeter
•Non-linear output