NANO-ELECTRO-MECHANICAL SYSTEM(NEMS)

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NANO-ELECTRO-MECHANICAL SYSTEM(NEMS)
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contents

• Introduction
• Benefits of Nano-machines
• Fabrication of NEMS device
• Advantages
• Applications
• Summary

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• INTRODUCTION
• Nano-Electro-Mechanical system (NEMS) is the
  integration of mechanical elements, sensors,
  actuators and electronics on a common
  silicon substrate.
• The Nano mechanical components are fabricated
  using compatible micromachining process.
• NEMS is the enabling technology allowing the
  development of smart products.

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• 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.

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• 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.

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• BENEFITS OF NANO MACHINES
• Nano-Mechanical devices promise to revolutionize
  measurements of extremely small displacements
  and forces.
• Can built with the masses approaching a few
  attograms(10-18g) and with the cross section of
  10nm.
• A second important attribute Nano machines is
  that they dissipate less energy.

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• NEMS are extremely sensitive for the external
  damping mechanisms which is crucial for building
  sensors.
• The Geometry of a NEMS device can be tailored so
  that the vibrating elements reacts only to
  external forces in a specific direction.
• NEMS are ultra low power devices.
• Fundamental power scale is defined by the thermal
  energy divided by the response time

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

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• Deposition Process
• One of the basic building blocks in NEMS
  processing is the ability to deposit thin films
  of materials.
• Thin films of thickness of about few nm to about
  100 nm.
• Chemical methods used in NEMS deposition
  process.
• Chemical vapour deposition.
• Epitaxy.

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

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• Epitaxy
• Fig 2 Typical cold-wall vapour phase
• epitaxial
  reactor

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• 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.

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• Pattern Transfer
• Fig 3 Transfer of a pattern to a
  photosensitive material

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

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• Alignment
• Inorder to make useful devices the patterns for
  different lithography steps that belongs to a
  single structure must be aligned to one another.
• The first pattern includes a set of alignment
  marks.
• The first pattern alignment marks used as the
  reference when positining subsequent patterns.

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• 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

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• 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.

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• Wet etching
• This is the simplest etching technology.
• There are complications since usually Mask is
  desired to selectively etch the material.
• It requires a container with a liquid solution
  that dissolve the material used.
• Some single crystall material, such as silicon,
  exhibits anistropic etching in certain chemicals.

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• ADVANTAGES
• Cost effectiveness.
• System integration.
• High Precision.
• Small size.

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

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• 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.

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• 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.

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

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• SUMMARY
• 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.

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• 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.

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• THANK YOU