An introduction to MEMS Technology is presented.

1. MEMS:A Primer
A Presentation By-
A.S. Kurhekar
http/sites.google.com/site/anilkurhekar100
/

2. Definition
 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

3. Device Dimensions
 The critical physical dimensions of MEMS devices
below one micron on the lower end of the
dimensional spectrum, all the way to
several millimeters
 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

4. The Functional Elements of
MEMS
 The functional elements of MEMS are
miniaturized structures
 Sensors
 Actuators
 and microelectronics
 The most notable elements are
 microsensors
 microactuators

5. Transducers
 Microsensors and microactuators are
appropriately categorized as
“transducers”, which are defined as
devices that convert energy from one
form to another. In the case of
microsensors, the device typically
converts a measured mechanical signal
into an electrical signal

6. A few applications of current
interest
 Biotechnology
 Polymerase Chain Reaction (PCR) microsystems for DNA
amplification and identification, enzyme linked immunosorbent
assay (ELISA), capillary electrophoresis, electroporation,
micromachined Scanning Tunneling Microscopes (STMs),
biochips for detection of hazardous chemical and biological
agents, and microsystems for high-throughput drug screening
and selection
 Medicine
 MEMS pressure sensors may be used to measure intrauterine
pressure during birth. The device will be housed in a catheter
that is placed between the baby's head and the uterine wall.
During delivery, the baby's blood pressure is monitored for
problems during the mother's contractions

7. A few applications of current
interest
 The MEMS pressure sensors in respiratory monitoring are used
in ventilators to monitor the patient’s breathing
 Communications
 RF-MEMS technology
 Electrical components such as inductors and tunable capacitors
can be improved significantly compared to their integrated
counterparts if they are made using MEMS and Nanotechnology
 With the integration of such components, the performance of
communication circuits will improve, while the total circuit area,
power consumption and cost will be reduced
 In addition, the mechanical switch, is a key component with
huge potential in various RF and microwave circuits
 Another successful application of RF-MEMS is in resonators as
mechanical filters for communication circuits

8. A few applications of current
interest
 Inertial Sensing
 MEMS inertial sensors
 Accelerometers and Gyroscopes, For example, MEMS
accelerometers have displaced conventional accelerometers for
crash air-bag deployment systems in automobiles
 MEMS technology has made it possible to integrate the
accelerometer and electronics onto a single silicon chip These
MEMS accelerometers are much smaller, more functional,
lighter, more reliable, and are produced for a fraction of the
cost of the conventional macro-scale accelerometer elements
 MEMS gyroscopes (i.e., rate sensors) may be designed for both
automobile and consumer electronics applications
 MEMS inertial sensors may be used in every car sold as well as
notable customer electronic handhelds such as Apple iPhones
and the Nintendo Wii

9. Nanotechnology Agenda
 What is nanotechnology and why is it
important?
 Some history and characterization
techniques
 Examples of nanomaterials, research,
applications, and emerging trends
 Introductions
 Final (opening) motivation and advice

10. Nanotechnology Definition
Nanotechnology is the ability to understand, control,
and manipulate matter at the level of individual
atoms and molecules as well as at the
“supramolecular level” involving clusters of
molecules, in order to create materials, devices, and
systems with fundamentally new properties and
functions because of their small structure. The
definition implies using the same principles and tools
to establish a unifying platform for science and
engineering at the nanoscale, and employing the
atomic and molecular interactions to develop
efficient manufacturing method
National Science Foundation (NSF)
National Nanotechnology Initiative (NNI)

11. How big a nanometer is ?

12. Beneath 1 millimeter

13. Need: education
A key challenge for nanotechnology development
is the education and training of a new
generation of skilled workers in the
multidisciplinary perspective necessary for
rapid progress of the new technology
The concept at the nanoscale (atomic, molecular
and supra-molecular levels) should penetrate
the education system in the next decade in a
similar manner to how the microscopic
approach made inroads in the last forty to fifty
years…

14. Nanomaterials are not “New”
 It is probable that “soluble” gold appeared around the 5th
or 4th century B.C. in Egypt and China
 The Lycurgus Cup that was manufactured in the 5th to
4th century B.C. It is ruby red in transmitted light and
green in reflected light, due to the presence of gold
colloids
 In 1857, Faraday reported the formation of deep red
solutions of colloidal gold by reduction of an aqueous
solution of chloroaurate (AuCl4) using phosphorus in
CS2(a two-phase system) in a well known work
 Faraday investigated the optical properties of thin films
prepared from dried colloidal solutions and observed
reversible color changes of the films upon mechanical
compression (from bluish-purple to green upon
pressurizing).

15. Ability to be nanoscientists is new
 So, nanomaterials are definitely not
new!
 but our ability to be nanoscientists is
new, because we’ve created instruments
and machines for controlled
characterization and fabrication
 these enable nanotechnology

16. The Electron Microscope
Goodhew, Microscopy and Microanalysis

17. Scanning probe microscopes
invented by Young and colleagues, NIST,
1972
Binnig and Rohrer, Nobel Prize, 1986
Binnig, Quate, Gerber, 1986
Scanning tunneling microscope (STM) Atomic force microscope (AFM)

18. Nano-scale
Nanotube on a
scanning probe tip
This is about how big atoms are
compared with the tip of the microscope
About 25 nanometers

19. Current resolution limits approach
visibility of individual atoms and defects

20. Building blocks
Nanoclusters / Nanoparticles Magic #’s of atoms
100s-1000s of atoms≤1 nm size
~1-100 nm diameter
Nanowires / Nanotubes
Filled Hollow
~1-100 nm dia, up to mm long and beyond!

21. Semiconducting Nanocrystals:
“Quantum Dots”
photo by F. Frankel, MIT
Hodes, Advanced Materials, 19:639, 2007.
<100> CdSe <001> CdSe

22. Nanowire chemical sensors
- Molecule-sized binding sites = high S/N
-Engineer binding to be molecule
-Specific Arrays can be multiplexed to
detect lots of markers
Patolsky and Lieber, Materials Today,2007.
Principle of carrier injection

23. CNT Based Memory
Reversible electromechanical junction
Rueckes et al, Science 289, 2000; http://www.nantero.com

24. An SiO2 Micro-cantilever Fabricated
by Me at IITB

25. A Beautiful Micro-cantilever
Fabricated by Me at IITB

26. Micro-cantilevers

27. Micro-mirrors

28. Micro-needles : Trans-dermal
Drug Delivery

29. MEMS-Diaphragm: A Pressure
Sensor

30. Nanopowders

31. Nanogold
 Well… strange things happen at the
small scale
 If you keep cutting until the gold
pieces are in the nano-scale range,
they don’t look gold anymore…
They look RED!
 In fact, depending on size, they can
turn red, blue, yellow, and other
colors
 Different thicknesses of materials
reflect and absorb light differently
12 nm gold particles look red
Other sizes are other colors

32. Fabrication Methods
 Atom-by-atom assembly
 Like brick-laying, move atoms
into place one at a time using
tools like the AFM and STM
 Chisel away atoms
 Like a sculptor, chisel out
material from a surface until the
desired structure emerges
 Self assembly
 Set up an environment so atoms
assemble automatically. Nature
uses self assembly (e.g., cell
membranes)
IBM logo assembled from
individual xenon atoms
Polystyrene spheres
self-assembling

33. Example: Self Assembly By Crystal
Growth
 Grow nanotubes like trees
 Put iron nanopowder crystals on a
silicon surface
 Put in a chamber
 Add natural gas with carbon (vapor
deposition)
 Carbon reacts with iron and forms a
precipitate of carbon that grows up
and out
 Because of the large number of structures
you can create quickly, self-assembly is
the most important fabrication technique Growing a forest of
nanotubes!

34. Nanotech Meets Contact
Lenses and Virtual Reality
 Nanotech could end up providing a solution
to the need for bulky headsets in virtual
reality environments, and the answer
involves contact lenses.
 A platform embedded a center filter and
display lens at the center of a contact lens.
The optical elements are smaller than the
eye's pupil and therefore do not interfere
with vision. A projector can hit those tiny
optical elements, which guide images to the
retina. But the retina is still getting the
overall normal vision provided through the
entire pupil, so the brain ends up viewing the
projected images and the overall normal field
of vision as one.

35. A Nanotech Detector for
Heart Attacks
 Nanosensors that detect heart attacks before they happen could save
both lives and money
 Technology involves
tiny blood stream nanosensor chips
that might sense the precursor of a heart attack. A person with such a
tiny chip might get a warning on their smart-phone or other wireless
device that they should immediately see their cardiologist.
 The sensors are now being used for glucose detection in animal
studies. Human trials should follow thereafter
 nanosensor + coupled smart-phone = track autoimmune disease and
cancer

36. Dragonfly-Inspired Black Silicon
Fights Off Bacteria
 An array of antibiotic surfaces can be found in the
natural world, inspiring scientists to develop man-made
versions of them. A recent example of this trend can be
found in research from Australian and Spanish scientists
who have developed a nanomaterial out of black
silicon with tiny spikes on its surface. The surface
geometry of the material is similar to that of the wings
of an Australian dragonfly known as the
“wanderingpercher,” whose wings have tiny spikes that
inhibit bacterial growth.
In the lab, the scientists confirmed that the black silicon
material proved to be effective against an array of
Gram-negative and Gram-positive bacteria as well
as endospores. The researchers report that the
breakthrough is the first “physical bactericidal activity of
[black silicon] or indeed for any hydrophilic surface.”

37. Tiny 3-D Printed Batteries
 “inks,” able to function as electrochemically active
materials. The materials also had to harden into layers in
just the right way so they could be stacked up in layers
during the 3-D printing—creating working anodes and
cathodes
 The recipe includes
ink for the anode with nanoparticles of one lithium metal
oxide compound, + an ink for the cathode from
“nanoparticles of another =The printer lays the ink onto
the teeth of two gold combs to create a tightly interlaced
stack of anodes and cathodes
The whole setup gets packaged into a tiny container and
filled it with an electrolyte solution to complete the battery

38. Revolutionizing Eye Surgery
 A tiny magnetically-guided microbot was designed to be embedded in
the eye to perform precision surgery or to deploy precise amounts of
drugs
 The magnetic microbots are powered using external magnetic fields.
Known as the OctoMag, the robots can produce magnetic forces
and torques in three dimensions. The robot is so small that it could be
used to help dissolve clots in the vessels of the eye
 The size of autonomous microrobots has been historically limited by
motors and propulsion devices. The OctoMaggets around this
requirement by using an external magnetic control system that can
guide a needle-injected device into the eye, eliminating the need to
slice the eye open.

39. Super-flexible Chips that Can
Encircle a Strand of Hair
 nanotech-based electronic chips that are so flexible they can be
wrapped around a hair strand
 were able to accomplish this feat by creating thin layers of
stacked polyvinyl that is topped with an electronic circuit.
 When submerged in water, two of the polyvinyl layers dissolve,
leaving a tiny circuit embedded on a sheet of parylene that is
one micrometer thick
 The researchers found that the transistors still function when
wrapped around a human hair. The flexible electronics can
adhere to a range of materials. Potentially suited for wearables
and a whole range of medical applications, the chip has already
been used in an artificial eye and in a glaucoma monitor

40. Creating Biodegradable
Electrodes
 They ended up finding out that naturally
occurring melanins derived from cuttlefish ink
exhibit higher charge storage capacity compared to
other synthetic melanin derivatives when used as
anode materials
 But not everything swallowed by a patient needs
to be digestible. “You know, anybody who's ever
taken a drug in their life probably hasn't adhered
exactly to what the prescription says, or what the
doctor says, so adherence is a very big issue in the
industry,”

41. Nanotech Cancer Apps
 nanoparticles that carry the cancer
drug doxorubicin, as well as short
strands of RNA that can shut off one of
the genes that cancer cells use to
escape the drug. The researchers were
searching for ways to treat an especially
aggressive form of breast cancer

42. Silver Germ-Killers
 Silver nanoparticles are increasingly
being used in everything from self-
sanitizing toothbrushes to clothes. It
may eventually be used in toothpaste.
 The ability of tiny particles of silver to
kill bacteria has been known for some
time, though the research appears to
be light on whether the silver also
carries health risks.

43. Nanotech-Enabled Breathalyzer
for Diabetics
 The ability to detect acetone in the breath is
derived from acetone-sensitive nanometer-
thick polymeric films. Exposure to acetone
causes the two polymers in the films
to crosslink, changing its physicochemical
nature
 The breathalyzer prototype is roughly the
size of a book. The researchers are working
on shrinking the technology to yield a
breathalyzer with a similar size to those
used by police to detect blood alcohol
content levels

44. Collaborate and learn from others
“The thing I want to say is collaborate. Collaborating with
talented people is not easy, but it’s the way to really shine –
you shine brighter if you are working with really great people.
The important thing in the end is not that you are proved
right every time, the important thing is that the music is the
best that it can be. I want to wish you all that you would find
your own voice. But if you are so disposed that you would find
collaborators to work with, that you would shine as you could
never shine on your own.”
Dave “The Edge” Evans (U2), at Berkley College of Music
Commencement, Boston, MA, May 2007.

45. A Quiz !!!
1. How big is a nanometer compared to a meter? List one object
that is nano-sized, one that is smaller, and one that is larger
but still not visible to the naked eye
2. Name two properties that can differ for nano-sized objects and
much larger objects of the same substance. For each property,
give a specific example
3. Describe two reasons why properties of nano-sized objects are
sometimes different than those of the same substance at the
bulk scale
4. What do we mean when we talk about “seeing” at the nano-
scale?
5. Choose one technology for seeing at the nano-scale and briefly
explain how it works
6. Describe one application (or potential application) of nano-
science and its possible effects on society

46. A Quiz !!!
7. What is MEMS
8. What are accelerometers and micro-
cantilevers
9. Why MEMS technology should be married to
Nanotechnology
10.What are Quantum Dots and Micro-needles

47. For patient listening……………..
Thank You.