MEMS micro electro mechanical systems is an advanced field of engineering which has many scientific applications.
This PPT summarizes about mems, the materials used in mems, materials used in mems, their uses, pros and cons, advantages disadvantages etc..
2. Introduction
• Micro Electro Mechanical Systems are small
integrated devices which combines electronics,
electricals as well as mechanical components
whose size ranges from 1 micrometre to 100
micrometres.
• MEMS are also referred to as Micro Machines in
Japan, and Micro Systems Technology (MST) in
Europe.
• MEMS devices are fabricated by using modified
micromachining techniques.
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3. History
• MEMS were first proposed in 1960s.
• They were commercialized in 1980s.
• The first commercial use of MEMS was tiny nozzle
assembly used in the cartridges of inkjet printers.
• In 1982, automotive airbag systems were introduced
using MEM sensors to detect a crash.
• The Analog devices corporation elaborated this
idea, producing an accelerometer for airbag systems
in 1991.
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5. silicon
• Silicon is the material which is used to create most integrated circuits
used in consumer electronics in the modern industry.
• Silicon also has significant advantages engendered through its
material properties.
• In single crystal form, silicon is an almost perfect Hookean material,
meaning that when it is flexed there is virtually no hysteresis and
hence almost no energy dissipation.
• Silicon is very reliable as it suffers very little fatigue and can have
service lifetimes in the range of billions to trillions of cycles without
breaking.
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6. polymers
• Even though the electronics industry provides an economy of scale for
the silicon industry, crystalline silicon is still a complex and relatively
expensive material to produce.
• Polymers on the other hand can be produced in huge volumes, with a
great variety of material characteristics.
• MEMS devices can be made from polymers by processes such as
injection moulding, embossing or stereo lithography and are
especially well suited to microfluidic applications such as disposable
blood testing cartridges.
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7. metals
• Metals can also be used to create MEMS elements.
• While metals do not have some of the advantages displayed by silicon
in terms of mechanical properties, when used within their limitations,
metals can exhibit very high degrees of reliability.
• Metals can be deposited by electroplating, evaporation, sputtering
processes.
• Commonly used metals include gold, nickel, aluminium, copper,
chromium, titanium, tungsten, platinum, and silver.
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8. ceramics
• The nitrides of silicon, aluminium and titanium as well as silicon carbide
and other ceramics are increasingly applied in MEMS fabrication due to
advantageous combinations of material properties.
• Aluminium nitride crystallizes in the wurtzite structure and thus shows
pyroelectric and piezoelectric properties enabling sensors, for instance,
with sensitivity, to normal and shear forces.
• Moreover, the high resistance of titanium nitride against bio corrosion
qualifies the material for applications in bio genic environments and in bio
sensors.
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9. Applications
1. Inkjet printers
2. Accelerometer in modern cars for air bag
deployment
3. Inertial measurement unit
4. Microphones in portable devices like mobile
phones
5. Accelerometer in electronic devices like game
controllers
6. Silicon pressure sensors
7. Displays like digital micro mirror device
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10. 8. Optical switching technology
9. Bio mems in bio medical sector
10. Interferometric modular display (IMOD)
11. Fluid acceleration for micro cooling
12. Micro scale energy harvesting like
a) Piezo electric micro harvester
b) electro static micro harvester
c) Electro magnetic micro harvester
13. Micro machined ultra sound transducers
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11. Advantages
• Minimized use of materials.
• Improved reproducibility.
• Improved sensitivity, accuracy and reliability.
• Low power consumption.
• Easier to alter the parts of a device as compared to its macro counterpart.
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12. Disadvantages
• Poly silicon is brittle material, hence it can be broken under stress.
• Understanding the mechanical properties of mems is very hard as it is very
small.
• Sometimes designs can be very complex.
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13. conclusion
• The MEMS technology bought drastic changes in technology in past few decades.
• It will be the promising career for researchers and investors.
• This technology is base for the next era of human development.
• MEMS can be used in many multidisciplinary fields like biomedical, biomechanics,
aerospace industries.
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