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Radiation Hardened Carbon Nanotube-based Nonvolatile Memory


OBJECTIVE: Develop a high capacity carbon nanotube memory device suitable for use in space memory application. DESCRIPTION: With conventional silicon based photolithography techniques rapidly approaching the physical limits of feature size reductions, new miniaturization approaches will be necessary to advance density for future generations of radiation hardened satellite memory devices. Recent research in carbon nanotube (CNT) based Resistive RAM has opened possibility of ultra miniaturizing phase change memory feature sizes below what can be achieved through conventional photolithographic fabrication approaches. For example, when CNT is transferred to RRAM (Resistive Random Access Memory) it was possible to create a 6- by 6-nm (nanometer) memory cell. Evaluation of CNT (Carbon Nanotube) based memory suggests that it is inherently radiation hard making it an ideal candidate for operation in space. Before radiation hardened nanotube memory is viable for insertion into space, a fabrication process must be developed and proven that is both reliable, affordable, and of a density that makes it attractive for insertion into future space programs. Obstacles include achieving a reliable and high yield production process, including precision control of cross-wire patterns, spacing and tube growth. The purpose of this topic is to support the development of a radiation hardened CNT or graphene memory device suitable for insertion into geosynchronous satellite applications. Goals include density>16M bits per device, radiation tolerance>1Mrads(Si) total dose, access time<10ns (read), immunity from Single Event (SEE) radiation effects and extended operating temperature range (55 to +125 degrees Centigrade). PHASE I: Design a CNT/graphene based memory and validate the design through modeling and simulation. Perform test and evaluation of the technology proposed through basic materials characterization and prototyping. PHASE II: Fabricate nanotube and/or graphene memory device at a density that can verify the technology (less than 16Mb is acceptable) based on phase I design and characterize for access time, mean-time-to failure, operating voltage, radiation characteristics, and operating temperature range. PHASE III: High capacity carbon nanotube (or graphene) memory device will be suitable for use in Military space memory applications. There will be significant uses also for commercial satellite applications. REFERENCES: 1. Courtland, R. ,"Flash challengers work well at nanoscale,"Spectrum, IEEE , vol.48, no.8, pp.18, August 2011. 2. P. Avouris,"Molecular electronics with carbon nanotubes,"Accounts of Chemical Research, vol. 35, pp. 10261034, 2002. 3. N. Patil, J. Deng, S. Mitra, and H.-S. Wong,"Circuit-level performance benchmarking and scalability analysis of carbon nanotube transistor circuits,"Nanotechnology, IEEE Transactions on, vol. 8, no. 1, pp. 37 45, 2009.
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