Nems2

Nano electromechanical systems
Presented by
SYEDA NASIHA

INTRODUCTION
 Nano-Electro-Mechanical systems (NEMS) integrate
electrical and mechanical functionality on the
nanoscale.
 The Nano mechanical components are fabricated
using compatible “micromachining” process.

 Nano electro mechanical devices promise to
revolutionize measurements of extremely small
displacement and extremely weak forces,
particularly at the molecular level.
 NEMS devices can be so small that hundreds of
them can be fit in the same space as one single
micro device that performs same function.

 Nano-electronic integrated circuits allow nano systems to
sense and control the environment.
 In Nems devices the sensors gather the information from
surrounding environment through measuring mechanical,
chemical, biological, chemical and optical phenomenon.
 The electronics then process the information derived form
the sensors.
 Through some decision making capability direct the actuators
to respond by moving, regulating and filtering.

 Electro mechanical systems:
 The device illustrates the two principal components
common to most electromechanical systems irrespective
of scale:
 a mechanical element:includes moveable structures such
as beams,gears.
 transducers.:small motors and integrated circuits.
 the output of an electromechanical device is the
movement of the mechanical element.

BENEFITS OF NANO MACHINES
 The small mass and size of Nano machines gives them
a number of unique attributes that offer immense
potential for new applications and fundamental
measurements.
 A second important attribute Nano machines is that they
dissipate less energy.

 Nano machines are extremely small .
 Nano machines are ultra low power devices.
 Fundamental power scale is defined by the thermal
energy divided by the response time

fabrication of nems device
 There are three Basic building blocks in NEMS
technology.
 Deposition processes.
 Lithography.
 Etching processes.

Deposition Process :
 Chemical methods used in NEMS deposition
process.
o Chemical vapour deposition.
o Epitaxy.

 Chemical vapour deposition :
Fig. 1: Typical hot-wall LPCVD reactor

 Epitaxy :
Fig 2: Typical cold-wall vapour phase
epitaxial reactor

 Lithography :
 Lithography in the NEMS context is typically the transfer
of a pattern to a photosensitive material by selective
exposure to a radiation source such as light.
 A photosensitive material is a material that experiences a
change in its physical properties when exposed to a
radiation source.

 Pattern Transfer :
Fig 3: Transfer of a pattern to a photosensitive material

Figure 4:a) Pattern definition in positive resist, b) Pattern
definition in negative resist.

Alignment :
 Inorder to make useful devices the patterns for different
lithography steps that belongs to a single structure must
be aligned to one another.
 It is important for each alignment mark on the wafer to
be labeled so it may be identified, and for each pattern to
specify the alignment mark to which it should be aligned.

 Exposure :
 This parameter is required in order to achive accurate
pattern transfer from the Mask to the photo sensitive
layer.
 Different Photo resist exhibit different sensitivity to
different wavelengths

 Etching :
 It is necessary to etch the thin films previously deposited
or the substrate itself.
 There are 2 class of etching process.
 Wet etching.
 Dry etching.

ADVANTAGES
o Cost effectiveness.
o System integration.
o High Precision.
o Small size.
o High sensitivity

APPLICATIONS OF NEMS
 Accelerometer :
NEMS accelerometers are quickly replacing
conventional accelerometers for crash air-bag
deployment systems in automobiles.
Figure 6 : Accelerometer(air bags)

 Nano nozzles:
 Another wide deployment of NEMS is their use as
nano nozzles that direct the ink in inkjet printers.
 They are also used to create miniature robots
(nano-robots) as well as nano-tweezers.
 NEMS have been rigorously tested in harsh
environments for defense and aerospace where
they are used as navigational gyroscopes.

 NEMS in Wireless :
 A 3G “smart” phone will require the functionality of
as many as five radios – for TDMA, CDMA, 3G,
Bluetooth and GSM operation. A huge increase in
component count is required to accomplish this
demand.

 Thermal actuator :
 Thermal actuator is one of the most important NEMS
devices, which is able to deliver a large force with large
displacement.

DRAWBACKS
 NEMS technology is currently used in low- or medium-
volume applications. Some of the obstacles preventing its
wider adoption are:
 Limited Options
Packaging
Fabrication Knowledge Required

FUTURE OUTLOOK
 NEMS offer unprecedented and intriguing opportunities
for sensing and fundamental measurements.
 In the future, complex molecular-scale mechanical
devices will be mass-produced by placing millions of
atoms with exquisite precision or by some form of
controlled self-assembly. This will be true
nanotechnology.

 The focus on the exploration of NEM-physics and the
development of NEM-devices can be used as extremely
sensitive sensors for force and mass detection down to
the single molecule level, as high-frequency resonators
up to the GHz range
 Typically, high-frequency electrical resonators have Q
values less than several hundred.

CONCLUSION
 Nano-systems have the enabling capability and
potential similar to those of nano-processors .
 Since NEMS is a nascent and synergistic technology,
many new applications will emerge, expanding the
markets beyond that which is currently identified or
known.

 NEMS is forecasted to have growth similar to its
parent IC technology.
 For a great many applications, NEMS is sure to be
the technology of the future.

REFERENCES
[1] James E.Hughes Jr;Massimiliano Di Ventra;Stephane
Evoy(2004).”Introduction to nanoscale science and
technology”.
[2] Despont
M;Brugger,J;DRECHSLER,U;Durig,U;Haberle,W,Lutwyche
,M;Rothuizen,H;Stutz,R,et al(2000).”VLSI-NEMS chip for
parallel AFM data storage”.
[3] Ke,Changhong;Espinosa,Horacio D(2005).”Numerical
analysis of nanotube_based Nems devices_part 1”.
[4] “Global Market of NEMS projections”

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