Polymer memory

POLYMER MEMORY

Presented By

ABU DARDA M.Sc. (Polymer Science & technology)

13-PSTM-019DEPT. OF APPLIED CHEMISTRY.

ALIGARH MUSLIM UNIVERSITY,ALIGARH

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What is Polymer memory?

A leading technology in memory device development

Made out of electrically-conducting polymer (PEDOT)

Relatively denser and cheaper compared to flash memory

Advanced Micro Devices of Sunnyvale, California, is working with Coatue, a startup in Woburn, Massachusetts, to develop chips that store data in polymers rather than silicon.

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What is a PEDOT?

PEDOT-Poly(3,4-ethylenedioxythiophene) orPEDT A conducting polymer based on 3,4-ethylenedioxythiophene (EDOT monomer)

optical transparency in its conducting state

PEDOT has moderate band gap and low redox potential

PEDOT coatings possess high stability over different charge and discharge cycles and can be electrogenerated directly on a conductive support

http://upload.wikimedia.org/wikipedia/commons/0/05/PEDOT.png

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• PEDOT nanofibers are produced from vanadium pentoxide nanofibers by a nanofiber seeding method.

1. EDOT is dissolved in an aqueous solution of camphorsulfonic acid (CSA) and a vanadium pentoxide nanofiber sol-gel

2. Radical cationic polymerization is initiated by addition of ammonium persulfate.

3. The resulting polymer precipitates from solution and has a general composition (PEDOT)(CSA)0.11-(HSO4)0.12(Cl)0.11(H2O)0.19.

4. Washing with dilute HCl removes the vanadium compound. 5. The presence of the vanadium pentoxide seeds make the difference between

the formation of PEDOT nanofibers (100 to 180 nanometer diameter and one to several micrometres long)

6. The formation of a more conventional granular morphology. 7. When applied to a solid substrate such as PET, PEDOT non-woven films

have slightly less optical transparency and about half the conductance of commercial PEDOT:PSS / PET films

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Synthesis of PEDOT

PEDOT coatings possess high stability over different charge and discharge cycles and can be electrogenerated directly on a conductive support The material is a blend of

A negatively charged polymer called PSS-

A positively-charged one called PEDT+

Used as- Anti-static coating on camera film A photo-sensitive agent

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Conductivity of PEDOT

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About Technology

• The device sandwiches a blob of a conducting polymer called PEDOT (POLYETHYLENE DIOXYTHIOPENE)

• • Stores a megabit of data in a millimeter-square device -

10 times denser than current memories

• Turning the polymer into an insulator involves a permanent chemical change, meaning the memory can only be written to once

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Fabrication

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Architecture of Polymer Memory devices

• Each polymer is sandwiched between two electrodes which acts as memory cell

• A voltage is applied between top and the bottom electrodes

• Memory is represented as space charges in the polymers that are detected using electrical pulses

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Storing Data• stores information in an entirely different manner than

silicon devices

• store data based on the polymer’s electrical resistance

• Application of an electric field to a cell lowers the polymer’s resistance, thus increasing its ability to conduct current;

• the polymer maintains its state until a field of opposite polarity is applied to raise its resistance back to its original level.

• • The different conductivity states represent bits of

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Read / Write Data

For Writing

•To store the memory, it use the wires and the diode surrounding the PEDOT blob to run either a high or a low current through it.

For reading•To read the memory, they run current through the top wire and measure the current in the bottom wire.•No current means the bit is a zero, and vice versa

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Features of Polymer Memory

• Data stored by changing the polarization of the polymer between metal lines

• Zero transistors per bit of storage

• Microsecond initial reads. Write speed faster than NAND and NOR Flash

• Simple processing, easy to integrate with other CMOS

• No cell standby power or refresh required

• Operational temperature between -40 and 110°C12/21/14

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• Polymer memory layers can be stacked This enable to achieve very high storage capacity.

• Memory is Nonvolatile• Fast read and writes speeds• Very low cost/bit, high capacity per rupee• Low power consumption• Easy manufacture, use ink-jet printers to spray liquid-

polymer circuits onto a surface• 10xFaster than conventional memory devices

Advantages of Polymer memory?

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• One million bits of information could fit into a square millimeter of material the thickness of a sheet of paper. A block just a cubic centimeter in size could contain as many as 1,000 high-quality digital images

• Scientists suggest, and producing it wouldn't require high temperatures or vacuum chambers.

• Unlike a CD, reading data stored on this memory block does not involve any moving parts or a laser. Instead it can be plugged directly into a circuit.

• It’s a very cheap technology which gives it a upper hand over other technology.

• A PEDOT-based machine could solve the problem of virus hackers, who rely on the fact they cannot afford to leave a trace out of fear of being caught for their dirty work. With PEDOT-based solutions hackers would not be able to erase their IP addresses.

Facts and Fiction

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• It can be read many times but it can be write only ones

• The biggest challenge is developing production technique

• This technology is still under research, so it will take time to launch in the market

Limitations of Polymer memory?

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WORM (WRite Once Read Many) type MeMORy applicatiOns

peRManent stORage such as in hOlOgRaphy techniques

ROM devices

Applications

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• It is 10 times denser than current magnetic memories.

• Store mega-bit of data in millimeter-square device.

• Data can’t be rewritten so suitable for permanent storage

• It requires only few transistors.

• It cost about 5% as much to manufacture compared to silicon-based memory.

• Retain data without power.

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Conclusion

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• Zhang, Xinyu; MacDiarmid, Alan G.; Manohar, Sanjeev K. (2005). "Chemical synthesis of PEDOT nanofibers". Chemical Communications (42): 5328–30. doi:10.1039/b511290g. PMID 16244744

• Unfolding space, memory by N. Nagaraj Financial Daily from THE HINDU group of publications

• Technical paper, "Memory Device Applications of a Conjugated Polymer: Role of Space Charges," Journal of Applied Physics, February 15, 2002

• . www.detnews.com

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References

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• A. Prakash, J. Ouyang, and J. Lin, “Polymer memory device based on conjugated polymer and gold nanoparticles,” J. Appl. Phys., vol. 100, no. 5, pp. 1–5, 2006

• C. Perlov, W. Jackson, C. Taussig, S. Mo, and S. R. Forrest, “A polymer / semiconductor write-once read-many-times memory,” Nature, vol. 426, no. November, 2003

• MIT Technology Review 03 / 02 –Improved Memory

• MIT Technology Review 09 / 02 – Polymer Memory

• http://upload.wikimedia.org/wikipedia/commons/0/05/PEDOT.png www.intel.com

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References

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