Multilevel ultra-fast and disturb-free flash memory with double embedded Au and Gd2O3 nanocrystals

Ultra-fast (μsec) and disturb-free multilevel flash memory was demonstrated by a novel gold and gadolinium oxide bi-nanocrystals (BNCs). Through nanocrystal band engineering design and using a new operation scheme, the BNCs memory exhibits an ultra-fast program and erase speed for 3.5μsec and 5μsec respectively, which is three orders faster than the conventional one. A disturb-free behavior is achieved for operating under -14 to 9 V. The threshold voltage memory window (2.78 V for 4 bits) closure is only 7.3% under 10⁸ cycling and with only 10% charge loss for 10⁴ sec retention. The activation energy of charge loss and trapped charge centroid were extracted to identify the nanocrystal band engineering and carrier injection mechanism.