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Carbon Nanotube Memory
Ricky Taing
Outline
Motivation for NRAM Comparison of Memory
NRAM Technology Carbon Nanotubes Device Operation Evaluation
Current State of NRAM Fabrication
Conclusions
Motivations and Goals
Physical limitations of current memory Threshold voltage scaling, soft error
Low power for mobile devices Universal memory
Fast, dense, non-volatile, low energy
Comparison - Current Tech
Size compared to DRAM Speed compared to SRAM Energy compared to Flash
limited lifetime for flash
Comparison - Future Tech
MRAM (Magnetic Memory) Insulator separated magnetic plates
Changing polarity causes high or low resistance across insulator size limit being reached, larger than flash
FRAM (Ferroelectric Memory) replace capacitor with Ferroelectric crystal in use
unlimited writes smallest possible size larger than NRAM
Josephson based
NRAM Technology
Carbon Nanotubes cylindrical carbon molecules extremely strong (52x carbon steel) SWNT
conductors composite fibers: 600 J/g to break
4x spider silk, 18x Kevlar fiber
“Gecko strength” 200x as sticky
NRAM Technology
NRAM Technology
Device Overview
NRAM Technology
On/Off States Potential Energy Van der Waals interactions Keeps state w/o current Threshold: 4.5V(on) and 20V(off)
NRAM
NRAM
NRAM Technology
Data Access OFF: high resistance ON: low resistance 100GHz operations for 10nm element
NRAM
NRAM Technology
Calculations Stable at room temperature States hold for a variety of sizes Measurable resistance difference Bending force will not strain strain SWNT Small voltages Localized interactions
NRAM Technology
Density 10^12 elements/cm^2
Speed current: 10x flash
Fabrication
Work with fabrication companies Current tech
Deposit nanotubes on chips Remove wrongly placed ones
Current State
Nantero “Made ground in the manufacturing process”
Density 13 cm circular wafers - 10GB
Future Space memory / BAE
Problems? fabrication
Conclusion
Stable, unlimited lifetime, instant on/standby, scalable
“Universal” NRAM prototype devices in 2006
