Nanocrystal Non-volatile Memory Devices
Kedar Patel
Liu et al (April 2006)Blauwe (Trans. on Nanotechnology, March 2002)Lin et al (TED, April 2006)
NV Memory Device
ProgrammingChannel Hot Electron injection or Fowler-Nordheim tunneling into poly or nc-Si
EraseFowler Nordheim tunneling to substrate or source
Quantum Scale!For 50nm x 50nm memory cell (transistor) and 1012 cm-
2 nanocrystal density:
25 nc per cell
For 32nm x 32nm memory cell (transistor) and 1012 cm-
2 nanocrystal density:
10 nc per cell
Fabrication• Excess Si-Precipitation
– Few 1-10keV, 1016 cm-2 Si implanted in SiO2 + 1000C N2 anneal
3-10nm nc-Si precipitates, ~1012 cm-2
• Aerosol Deposition– Pyrolysis of Silane (SiH4) at 950C
• Direct Deposition– LPCVD of Poly-Si; stop shortly after nucleation of
sites before a continuous film is formed
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