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MEMSMicro-Electro-Mechanical Systems
By:-Vikas poonia
(2013btec001L)
What is MEMS?Micro-Electro-Mechanical
Systems◦ is the integration of elements, sensors, actuators,
and electronics on a common silicon substrate through micro-fabrication technology, a manufacturing technology for making microscopic devices
◦Other Materials used in MEMS Gallium Arsinide Titanium Nickel Piezoelectric Materials
Micro Electro Mechanical Systems
Electrical sensing/actuation◦ Capacitive◦ Piezoelectric◦ Piezoresistive
Mechanical devices with a third dimension
Systems◦ Multiple functions on one
piece of silicon IMD
AMFitzgerald
AMFitzgerald
Size of MEMS
Birth of MEMS1970’s: using silicon
processing to make mechanical devices, not transistors◦Accelerometers◦Pressure sensors◦Inkjet nozzles
1982: Petersen’s “Silicon as a Mechanical Material”
Popular Science, June 1984
How MEMS are made! There are three main building blocks
in MEMS Deposition process
The ability to deposit thin films of material
Lithography is typically the transfer of a
pattern to a photosensitive material by selective exposure to a radiation source such as light
Etching Process Wet etching where the material
is dissolved when immersed in a chemical solution
Dry etching where the material is sputtered or dissolved using reactive ions or a vapor phase etchant
MEMS is a miniaturization technology
Airbag sensors (1980) Airbag sensors (2005)
MEMS belong where miniaturization is neededApplications using MEMS devices:
◦ Automotive: pressure, motion, sound, light, heat
◦ Consumer: motion, sound, pressure, compass
◦ RF: filters, resonators, switches, inductors◦ Optical: network components, displays,
switches, mirrors◦ Medical devices: needles, cell scaffolds,
ultrasound, implantables◦ Printing: inkjet, large format nozzles◦ Biotech: lab-on-chip microfluidics◦ Industrial: Atomic force microscopy,
chemical sensors
Smaller, better, cheaper◦ But not always all three!
Sophisticated capabilities in small form factor:◦ Multiple sensors◦ Signal processing and
analysis◦ Telemetry capability◦ Low power
Why MEMS are exciting for so many applications
Integrated Pressure
Sensor
MEMS sensor
Stacked MEMS and ASIC chips,
wirebonded
Applications of MEMS
• MEMS-based sensors are a crucial component in automotive electronics, medical equipment, smart portable electronics such as cell phones.
• PDAs, and hard disk drives, computer peripherals, and wireless devices.
• These sensors began in the automotive industry especially for crash detection in airbag systems.
Explosion of MEMS in consumer devices
Sophisticated capability in small form factor enabling new functions◦Motion sensing -> gesture input,
navigation◦Microphone arrays -> noise
cancellation◦Pressure sensing -> height detection
At the right price!◦MEMS took off when chip price <$3
MEMS enable exciting new products
MEMS are not like ICsYes, both are made on silicon wafersNo building block technology, i.e. no
transistor◦Moore’s law does not apply◦No standardization of design,
processes, or materials◦Each MEMS is custom-crafted
“One product, one process, one package”
What this impliesMEMS prices will not decrease as
fast as IC chips didMEMS sensor performance will
not improve as fast as microprocessors, memory chips did
Chip packaging usually critical to MEMS performance
System integration can be more challenging
ExpectedCharacteristics of MEMSIn the future, MEMS
Technology compared to Conventional Technology should have these effects:◦ Cost reduction◦ Increase functionality◦ Improve reliability◦ Decrease size◦ Decrease mass
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