Protein-assembled nanocrystal-based vertical flash memory devices with Al ₂O ₃ integration

This work presents vertical flash memory devices with protein-assembled PbSe nanocrystals as a floating gate and Al ₂O ₃ as a control oxide. The advantage of a vertical structure is that it improves cell density. Protein assembly improves uniformity of nanocrystals, which reduces threshold voltage variation among devices. The introduction of Al ₂O ₃ as a control oxide provided lower voltage/faster operation and hence less power consumption compared with the devices fabricated with SiO ₂. The integration of Al ₂O ₃ appeared to be compatible with the protein assembly approach. In conclusion, Al ₂O ₃ has the potential to become the high-k control oxide due to its relatively high electron/hole barrier heights, and high permittivity.