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EE235Carbon Nanotube Flash Memory
DevicesVolker Sorger
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Motivation
SymptomSymptom SourceSource
Robert Chau et. al, Intel Novel-Device-Group,Robert Chau et. al, Intel Novel-Device-Group,IEEE Nanotech.IEEE Nanotech. 2005 2005
G.; Fazio, A.; Mills, D.; Reaves B.G.; Fazio, A.; Mills, D.; Reaves B.Intel Technology J.Intel Technology J. Q4’97Q4’97
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Memories for Mobility
Non-volatile = low power neededNon-volatile = low power needed– power down to save powerpower down to save power
Low costLow cost– one memory for program & data storageone memory for program & data storage
≠≠magnetic hard diskmagnetic hard disk
Small form factor & light in weightSmall form factor & light in weight
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Future Perspectives of Non-volatile Memory
Molecular Tunnel(HP)
FeRAM
CNT based(Nantero Inc)
Resistance Polymer
ProgrammableMetallization
cell
OUM
MRAM
?
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CNT- Memory - Nanocrystals
‘‘0’0’
‘‘1’1’
Y. Zhang, APL, 2005 Y. Zhang, APL, 2005
Fit to Fit to
=800s @ 300K=800s @ 300K
tox=5nmtox=5nm IIdd
VVgg
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CNT- Memory – Si/SiO2 interface traps
M. Radosavljevic, Nano Lett., 2002 M. Radosavljevic, Nano Lett., 2002
Lack the ability to engineer Device parametersLack the ability to engineer Device parameters
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CNT Molecular Memory Idea similar to floating gate Flash memory
Control Gate
S D
DS
Control gate, Vp ~ 8V
tox~ 9 nm Floating gate
= ‘hot’ electrons
Vp = 1 – 4 V
Vsd~ 5 – 8 V
Vsd= 0 V
Control GateGate Oxide
Low static & dynamic Power Low static & dynamic Power
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Reversible switching & Multi-bit Programming
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@ 4.2 K
0 8 160.0
0.5
1.0
I/I (
t=0)
t (hr)
Single electron discharging
APL 82, 1787 (2003)APL 82, 1787 (2003)
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Results Sensitivity
Channel conductance vs. the gate voltage
0e
1e
2e
VVth th 0.28V per electron 0.28V per electron
Qdot=0,1e,2e
Vsd=0, VG=0.2V
SiO2
p++ Si
PdPd CNT
charge dot (Rdot)
dCNT~1.0nm, Lch=200nm, tbot=110nm, Rdot=0.3nm,
Collaboration withCollaboration with• Y. Zhang – IntelY. Zhang – Intel• Jing Guo - Florida U.Jing Guo - Florida U.
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Conclusion• Multi-bit programmable
• Single electron sensitivity at low T
• Low power consumption
• Integration (?)
~~~ Thank you for you attention ~~~~~~ Thank you for you attention ~~~