Micromechanical Nanographite Resonators Older
Transcript of Micromechanical Nanographite Resonators Older
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Characterisation ofnanographite for MEMS
resonators
Sam Fishlock, Harold Chong, John McBride,
Sean O’Shea, Suan Hui PuMS Fall meeting practice session
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Car&on materials for MEMS and'EMS
•
MEMS ( Micro Electro)Mechanical S*stems• +nestigated materials- diamond)like car&on, graphite,
graphene
• .pplications- resonators as mass sensors or oscillators and/lters for electronics
• 0ood mechanical properties and deice scala&ilit*• .+M- 1emonstrate fa&rication and characterisation of
nanographite MEMS resonators 2ithout transfer
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'anocr*stalline graphitedeposition
• 7)inch silicon 2afer su&strate
• O=ford instruments '.'OF.BPEC>1
• Scala&le and reproduci&le ?
standard microfabricationprocess
@emperature 5AC8 46
Methane o25sccm8
4
H*drogen o25sccm8
76
Pressure 5m@orr8 "466
F Po2er 5D8 "66
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Material characterisation•
aman and SEM con/rm nanocr*stalline grain structure• Electrical resistiit* "6%6 mG cm
• measurement I densit* ρ "966 kgm3
esistiit*&* electricalmeasureme
nts
"66nm
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Film stress
Stress gradientin the /lmK
K causescurature incantileers
.pplied
stress
.erage compressie stresscauses &uckling in C)C &eams
#6 um#6 um
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Simulation
• Modelled as classic &eams under tension 2here 'aturalfreNuenc* f aries 2ith - ;ength L , Stiness E, densit* ρ,Stress S and 0eometr* factor I,:
• .'SLS FE. simulation sho2s added
length due to the undercut 3Q
'ominallength
Eectie
length
2 2
2 21
EI SL f
L EI
π
ρ π
µ +
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;aser source
Split &eam I
1oppler shift usedto calculatei&rationamplitude
.ctuation and measurement• 1C V DC .C V 0 oltage creating electrostatic force F to
actuate the &eam
• S2eep .C oltage at freNuenc* f and measure the i&rationusing ;1> ( )( )2
0
1 12 sin 2
2 2 DC DC
C C F V V V ft
r r π
∂ ∂= ≈ +
∂ ∂
Measured "st i&ration mode
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esonance results
• >eri/cation from the FE. model
• Loung’s modulus from the cantileers is #3 0Pa
• FreNuenc* of the dou&l* clamped &eams dominated &*stress
Simulation for Loung’s modulus? #3 0Pa
Cantileerresults 1ou&l* clamped &eam results
9 MPa tensilestress
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esults ) Nualit* factor
36 m@orrT ("366
.m&ientT ( #6
• Tualit* factor UT’ I energ* loss at resonance% Calculatedfrom the FDHM of /tted cure
• ;osses are intrinsic, clamping, e=trinsic
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+ncreasing &iasoltage
@uning the naturalfreNuenc*
• +ncreasing the 1C &ias applies a compressie stressUelectrostatic spring softening’ to change the naturalfreNuenc*
• 6%34Q per olt aerage tuna&ilit*
•
'on)linearit* due to anchor shape
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Conclusions
• oute to standard fa&rication of thin nanographite andnanographene deices &* PEC>1
• Electrostaticall* actuated and tuned resonator deice
• ;o2 modulus, high stress material ? used the stress gradient
to create tensile deices 2hich raises the i&ration freNuenc*
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• Dr Suan Hui Pu
• Dr Harold Chong
• Prof John McBride
• 1r :ian :iang
• 1r O2ain Clark
• Mr Michael Perr*
• Dr Sean O’Shea
•
1r iaosong @ang• Mr .ndre2 Breeson
• 1r Me*samMirshekarloo
• Mr ;im Poh Chong
Sincere thanks to co-authors and technicalhelp
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Than !ou - "n!#uestions$