Combining Nanocrystals and Nanotubes for a New Electronic Memory
In flash memory, information is stored by placing electrical charge in a layer of insulator material above a semiconductor layer. The presence of the charge affects the electrical resistance of the semiconductor, thus providing a way to read-out the stored information. A major goal is to shrink such memory devices to the smallest possible size. CNS researchers working in collaboration with Intel have demonstrated a new variation on flash memory in which the charge is stored on a gold nanocrystal and the semiconducting sensing layer is replaced by a semiconducting carbon nanotube. The nanotube is extremely narrow (~ 1 nanometer) and charge flows through it in only a “single electron channel”, so that the presence or absence of just one extra electron on the nanocrystal can strongly affect the resistance of the nanotube. Further improvement of this new device structure could lead to very high density and low power memory applications.
[Lead CNS Investigator: E. Kan]
For additional information see:
- C. Lee, J. A. Meteer, V. Narayanan and E. C. Kan, “Process characterization of metal nanocrystal self assembly on ultra-thin oxide for nonvolatile memory applications”, J. Semiconductor Materials, vol. 34, no. 1, pp. 1-11, Jan. 2005.
- U. Ganguly, E. C. Kan and Y. Zhang, “Carbon nanotube based non-volatile memory with charge storage in metal nanocrystals”, Appl. Phys. Lett., vol. 87, p. 043108, 2005.
- C. Lee, U. Ganguly, V. Narayanan, T. Hou, J. Kim and E. C. Kan, “Asymmetric electric field enhancement in nanocrystal memories”, IEEE Elec. Dev. Lett., vol. 26, no. 12, pp. 879-881, Dec. 2005.
- C. Lee, T. Hou and E. C. Kan, “Nonvolatile memory with a metal nanocrystal/nitride heterogeneous floating gate”, IEEE Trans. Elec. Dev., vol. 52, no. 12, pp. 2697-2702, Dec. 2005.
- U. Ganguly, E. C. Kan, J. Guo, and Y. Zhang, “Carbon nanotubes – metal nanocrystal nonvolatile memory”, Material Research Society (MRS), San Francisco, CA, Mar. 29 – Apr. 1, 2005
- Lee, T.-H. Hou and E. C. Kan, “Metal nanocrystal/nitride heterogeneous-stack floating gate memory”, Device Research Conference (DRC), Santa Barbara, CA, June 2005
- U. Ganguly, J. Guo, E. C. Kan and Y. Zhang, “Carbon nanotube based non-volatile memory and charge sensors”, Proc. SPIE, Vol. SPIE, pp. 47-61, Nov. 2005