nano-electro-mechanical-system-nems.ppt

.

1. NANO-ELECTRO-MECHANICAL
SYSTEM(NEMS)

2. CONTENTS
Introduction
Benefits of Nano-machines
Fabrication of NEMS device
Advantages
Applications
Summary

3. INTRODUCTION
Nano-Electro-Mechanicalsystem(NEMS)isthe
integrationofmechanicalelements,sensors,actuators
andelectronicsonacommonsiliconsubstrate.
TheNanomechanicalcomponentsarefabricatedusing
compatible“micromachining”process.
NEMSistheenablingtechnologyallowingthe
developmentofsmartproducts.

4. Nanoelectromechanicaldevicespromiseto
revolutionizemeasurementsofextremelysmall
displacementandextremelyweakforces,particularlyat
themolecularlevel.
NEMSdevicescanbesosmallthathundredsofthem
canbefitinthesamespaceasonesinglemicrodevice
thatperformssamefunction.

5. InNemsdevicesthesensorsgathertheinformationfrom
surroundingenvironmentthroughmeasuring
mechanical,chemical,biological,chemicalandoptical
phenomenon.
Theelectronicsthenprocesstheinformationderived
formthesensors.
Throughsomedecisionmakingcapabilitydirectthe
actuatorstorespondbymoving,regulatingandfiltering.

6. BENEFITS OF NANO MACHINES
Nano-Mechanicaldevicespromisetorevolutionize
measurementsofextremelysmalldisplacementsand
forces.
Canbuiltwiththemassesapproachingafew
attograms(10-18g)andwiththecrosssectionof10nm.
AsecondimportantattributeNanomachinesisthatthey
dissipatelessenergy.

7. NEMSareextremelysensitivefortheexternaldamping
mechanismswhichiscrucialforbuildingsensors.
TheGeometryofaNEMSdevicecanbetailoredsothat
thevibratingelementsreactsonlytoexternalforcesina
specificdirection.
NEMSareultralowpowerdevices.
Fundamentalpowerscaleisdefinedbythethermal
energydividedbytheresponsetime

8. FABRICATIONOFNEMSDEVICE
There are three Basic building blocks in NEMS
technology.
Deposition processes.
Lithography.
Etching processes.

9. Deposition Process:
One of the basic building blocks in NEMS processing is
the ability to deposit thin films of materials.
Thinfilmsofthicknessofaboutfewnmtoabout
100nm.
Chemical methods used in NEMS deposition
process.
oChemical vapour deposition.
oEpitaxy.

10. Chemical vapour deposition:
Fig. 1: Typical hot-wallLPCVDreactor

11. Epitaxy:
Fig 2: Typical cold-wallvapour phase
epitaxial reactor

12. 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.

13. Pattern Transfer:
Fig 3: Transfer of a pattern to a photosensitive material

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

15. 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.

16. 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

17. 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.

18. Wet etching:
Thisisthesimplestetchingtechnology.
TherearecomplicationssinceusuallyMaskisdesiredto
selectivelyetchthematerial.
Itrequiresacontainerwithaliquidsolutionthatdissolve
thematerialused.
Somesinglecrystallmaterial,suchassilicon,exhibits
anistropicetchingincertainchemicals.

19. ADVANTAGES
oCost effectiveness.
oSystem integration.
oHigh Precision.
oSmall size.

20. APPLICATIONSOFNEMS
Accelerometer :
NEMS accelerometersarequicklyreplacing
conventionalaccelerometersforcrashair-bag
deploymentsystemsinautomobiles.
Figure6:Accelerometer(airbags)

21. 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.

22. NEMS in Wireless :
A3G“smart”phonewillrequirethefunctionalityofas
manyasfiveradios–forTDMA,CDMA,3G,
BluetoothandGSMoperation.Ahugeincreasein
componentcountisrequiredtoaccomplishthisdemand.

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

24. 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.

25. 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.

26. THANK YOU