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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 ~~~