Micro-Electro-Mechanical Systems, or MEMS, is a technology that in its most general form can be defined as miniaturized mechanical and electro-mechanical elements (i.e., devices and structures) that are made using the techniques of microfabrication. The critical physical dimensions of MEMS devices can vary from well below one micron on the lower end of the dimensional spectrum, all the way to several millimeters. Likewise, the types of MEMS devices can vary from relatively simple structures having no moving elements, to extremely complex electromechanical systems with multiple moving elements under the control of integrated microelectronics. The one main criterion of MEMS is that there are at least some elements having some sort of mechanical functionality whether or not these elements can move. The term used to define MEMS varies in different parts of the world. In the United States they are predominantly called MEMS, while in some other parts of the world they are called “Microsystems Technology” or “micromachined devices”.

3. Micro-Electro-Mechanical Systems
(MEMS)
SUBMITTED BY
NAME : ABHIJITH PM
CLASS : S4 EC
ROLL NO : 6
REG NO : 17200467
EMAIL ID : abhijithpm4112001@gmail.com
GUIDED BY MR.AIJU THOMAS (HOD. ELECTRONICS AND COMMUNICATION)

4. Micro-Electro-Mechanical Systems (MEMS)
Abstract :
MEMS technology consists of microelectronic elements, actuators, sensors, and
mechanical structures built onto a substrate, which is usually silicon. They are developed
using microfabrication techniques: deposition, patterning, and etching. The most common
forms of production for MEMS are bulk micromachining, surface micromachining, and HAR
fabrication. The benefits on this small scale integration brings the technology to a vast
number and variety of devices.

5. Introduction/Outline
- Story Time….
- History
- What Are MEMS?
- Components of MEMS
- Fabrication
- MEMS Operation
- Applications
- Summary
- 5 Key Concepts
- ?Questions?

6. HISTORY
Harvey C Nathanson
Kurt Petersen
George Atwood

8. What is a Sensor?
  A device used to measure a physical quantity(such as
 temperature) and convert it into an electronic signal of
 some kind(e.g. a voltage), without modifying the
 environment.
  What can be sensed?
 Almost Everything!!!
 Commonly sensed parameters are:
  Pressure
  Temperature
  Flow rate
  Radiation
  Chemicals
  Pathogens

9. 1958InventionoftheFirstIntegratedCircuit(IC)
Texas Instrument's First Integrated Circuit5
[Photos Courtesy of Texas Instruments]

10. 1947 Invention of the Point Contact Transistor (Germanium
First Point Contact Transistor and Testing Apparatus (1947)

11. What are MEMS?
• Made up of components between 1-100 micrometers in size
• Micro electro mechanical systems is the integration of mechanical elements
sensors actuators and electronics on a common silicon substrate through
microfabrication technology
• Devices vary from below one micron up to several mm
• Functional elements of MEMS are miniaturized structures, sensors, actuators,
and microelectronics
• One main criterion of MEMS is that there are at least some elements that have
mechanical functionality, whether or not they can move

12. Components
Microelectronics:
• “brain” that receives, processes, and makes decisions
• data comes from microsensors
Microsensors:
• constantly gather data from environment
• pass data to microelectronics for processing
• can monitor mechanical, thermal, biological, chemical,optical, and magnetic readings
Microactuator:
• acts as trigger to activate external device
• microelectronics will tell microactuator to activate device
Microstructures:
• extremely small structures built onto surface of chip
• built right into silicon of MEMS

13. Fabrication of mems
Deposition Patterning Etching
Physical Chemical Lithography Dry Wet
Photolithography
Electron beam lithography
Ion beam lithography
Ion-track technology
X-ray lithography

14. Basic Process of Fabrication
 Deposition
 Deposition that happen because of a chemical reaction or physical reaction.
 Patterning
 The pattern is transfer to a photosensitive material by selective exposure to a radiation source such as light.
 If the resist is placed in a developer solution after selective exposure to a light source, it will etch away.
 Etching
 Etching is the process of using strong acid to cut into the unprotected parts of a metal surface to create a design in.
 There are two classes of etching processes:
 Wet Etching
 Dry Etching.

15. MEMES Manufacturing Technologies

16. Bulk Micromachining
 This technique involves the selective removal of the substrate material in order to
realize miniaturized mechanical components.
 A widely used bulk micromachining technique in MEMS is chemical wet etching,
which involves the immersion of a substrate into a solution of reactive chemical that
will etch exposed regions of the substrate at very high rates.
Etched grooves using
(a) Anisotropic etchants,
(b) Isotropic etchants,
(c) Reactive Ion Etching (RIE )

17. Surface Micromachining
(a) Spacer layer deposition.
(b) Pattering of the spacer layer.
(c) Deposition of the microstructure layer.
(d) Patterning of desired structure.
(e) Stripping of the spacer layer resolves final structure.
 In surface micromachining, the MEMS sensors are formed on top of the wafer using deposited thin
film materials.

18. High Aspect Ratio (HAR) Silicon Micromachining
• Deep reactive ion etching (DRIE)
• Enables very high aspect ratio etches to be
performed into silicon substrates
• Sidewalls of the etched holes are nearly vertical
• Depth of the etch can be hundreds
or even thousands of microns into the silicon
substrate.
Wafer Bonding:
• Method that involves joining two or more
wafers together to create a wafer stack
• Three types of wafer bonding: direct bonding,
anodic bonding, and intermediate layer bonding
• All require substrates that are flat, smooth,
and clean in order to be efficient and successful

20. MEMS Operation
• Sensors & Actuators
• 3 main types of transducers:
o Capacitive
o Piezoelectric
o Thermal
• Additionally: Microfluidic

21. Inertial Sensors
MEMS Accelerometer
MEMS Gyroscope

23. Where Are MEMS?
 Smartphones, tablets, cameras, gaming devices, and many other electronics
have MEMS technology inside of them
http://www.chipworks.com/en/technical-competitive-analysis/resources/blog/inside-the-samsung-galaxy-s5/

24. In the Car

25. APPLICATIONS OF MEMS TECHNOLOGY

26. Biomedical Applications
Blood Pressure sensor
on the head of a pin
• Biomems
Bio-mems are used to refer to
the science and technology of
operating at the micro scale for
biological and biomedical
applications.
• In medicine
• A MEMS is a device
that can be implanted in the
human body.
• MEMS surgical tools provide the
flexibility and accuracy to perform
surgery.

27. Additional Applications
• Optical MEMS
o Ex: optical switches, digital micromirror devices
(DMD), bistable mirrors, laser scanners, optical
shutters, and dynamic micromirror displays
• RF MEMS
o Smaller, cheaper, better way to
manipulate RF signals
o Reliability is issue, but getting there

28. But why MEMS for sensors?
 Smaller in size
 Have lower power consumption
 More sensitive to input variations
 Cheaper due to mass production
 Less invasive than larger devices

29. • Much smaller area
• Cheaper than alternatives
○ In medical market, that means
disposable
• Can be integrated with electronics (system
on one chip)
• Speed:
○ Lower thermal time constant
○ Rapid response times(high frequency)
• Power consumption:
○ low actuation energy
○ low heating power
Benefits/Tradeoffs
• Imperfect fabrication
techniques
• Difficult to design on micro
scales

30. Summary/Conclusion
Micro-Electro-Mechanical Systems are 1-100 micrometer devices that convert electrical energy
to mechanical energy and vice-versa. The three basic steps to MEMS fabrication are deposition,
patterning, and etching. Due to their small size, they can exhibit certain characteristics that their
macro equivalents can’t. MEMS produce benefits in speed, complexity, power consumption,
device area, and system integration. These benefits make MEMS a great choice for devices in
numerous fields.
Thus we can conclude that the MEMS can create a proactive computing world, connected
computing nodes automatically, acquire and act on real-time data about a physical environment,
helping to improve lives, promoting a better understanding of the world and enabling people to
become more productive. MEMS promises to be an effective technique of producing sensors of
high quality, at lower costs

31. DIFFERENT MEMS DEVICES

32. • 1948 Invention of the Germanium transistor at Bell Labs (William Shockley)
• 1954 Piezoresistive effect in Germanium and Silicon (C.S. Smith)
• 1958 First integrated circuit (IC) (J.S. Kilby 1958 / Robert Noyce 1959)
• 1959 "There’s Plenty of Room at the Bottom" (R. Feynman)
• 1959 First silicon pressure sensor demonstrated (Kulite)
• 1967 Anisotropic deep silicon etching (H.A. Waggener et al.)
• 1968 Resonant Gate Transistor Patented (Surface Micromachining Process) (H. Nathanson,
et.al.)
• 1970’s Bulk etched silicon wafers used as pressure sensors (Bulk Micromachining Process)
• 1971 The microprocessor is invented
• 1979 HP micromachined ink-jet nozzle
• 1982 "Silicon as a Structural Material," K. Petersen
• 1982 LIGA process (KfK, Germany)
• 1982 Disposable blood pressure transducer (Honeywell)
• 1983 Integrated pressure sensor (Honeywell)
• 1983 "Infinitesimal Machinery," R. Feynman
• 1985 Sensor or Crash sensor (Airbag)
• 1985 The "Buckyball" is discovered
• 1986 The atomic force microscope is invented
• 1986 Silicon wafer bonding (M. Shimbo)
• 1988 Batch fabricated pressure sensors via wafer bonding (Nova Sensor)
• 1988 Rotary electrostatic side drive motors (Fan, Tai, Muller)
• 1991 Polysilicon hinge (Pister, Judy, Burgett, Fearing)
• 1991 The carbon nanotube is discovered
• 1992 Grating light modulator (Solgaard, Sandejas, Bloom)
• 1992 Bulk micromachining (SCREAM process, Cornell)
• 1993 Digital mirror display (Texas Instruments)
• 1993 MCNC creates MUMPS foundry service
• 1993 First surface micromachined accelerometer in high volume production (Analog Devices)
• 1994 Bosch process for Deep Reactive Ion Etching is patented
• 1996 Richard Smalley develops a technique for producing carbon nanotubes of uniform
diameter
• 1999 Optical network switch (Lucent)
• 2000s Optical MEMS boom
• 2000s BioMEMS proliferate
• 2000s The number of MEMS devices and applications continually increases
• 2000s NEMS applications and technology grows
LET’S FLY OVER TIME

33. References
• K. W. Markus and K. J. Gabriel,“MEMS: The Systems Function Revolution,” IEEE Computer, pp. 25-31, Oct. 1990.
• K. W. Markus, “Developing Infrastructure to Mass-Produce MEMS,” IEEE Comput. Sci. Eng., Mag., pp. 49-54, Jan. 1997.
• "What Is MEMS Technology?" What Is MEMS Technology? N.p., n.d. Web. 28 Apr. 2014.
• "Fabricating MEMS and Nanotechnology." Fabricating MEMS and Nanotechnology. N.p., n.d. Web. 28Apr. 2014.
• D. J. Nagel and M. E. Zaghloul,“MEMS: Micro Technology, MegaImpact,” IEEE Circuits Devices Mag.,pp. 14-25, Mar.
2001.
• M. E. Motamedi, "Merging Micro-optics with Micromechanics: Micro-Opto-Electro-Mechanical (MOEM) devices", Critical
Reviews of Optical Science and Technology, V. CR49, SPIE Annual Meeting, Proceeding of Diffractive and Miniaturized
Optics, page 302-328, July, 1993
• https://www.mems-exchange.org/MEMS/fabrication.html
• http://seor.gmu.edu/student_project/syst101_00b/team07/components.html
• http://www-bsac.eecs.berkeley.edu/projects/ee245/Lectures/lecturepdfs/Lecture2.BulkMicromachining.pdf
Images
• http://pubs.rsc.org/en/content/articlehtml/2003/AN/B208563C#sect274
• http://www.photonics.com/images/Web/Articles/2008/11/1/thumbnailhttp://www.docstoc.com/docs/83516847/Wh
at-are-MEMS
• http://seor.gmu.edu/student_project/syst101_00b/team07/images/MEMScomponents2.gif
• http://www.empf.org/empfasis/2010/December10/images/fig3-1.gif
• _35519.jpg
• https://www.memsnet.org/mems/fabrication.html

34. 5 Key Concepts
1. MEMS are made up of microelectronics, microactuators,
microsensors, and microstructures.
2. The three basic steps to MEMS fabrication are: deposition,
patterning, and etching.
3. Chemical wet etching is popular because of high etch rate and
selectivity.
4. 3 types of MEMS transducers are: capacitive, thermal, and
piezoelectric.
5. The benefits of using MEMS: speed, power consumption, size,
system integration(all on one chip).

35. Queries???...