High performance multi-bit nonvolatile HfO2 nanocrystal memory using spinodal phase separation of hafnium silicate

In this paper, we exploit a novel technique for preparing high density HfO₂ nanocrystals with an average size > 10nm using spinodal phase separation of Hf-silicate thin film by 900°C rapid thermal annealing for nonvolatile memories. The density can be as high as 0.9∼1.9×10¹²cm^-2. Owing to the fact that HfO₂ nanocrystals are well embedded inside SiO₂ matrix and their sufficiently deep energy level, we, for the first time, have demonstrated superior characteristics of the nanocrystal memory in terms of considerably large memory window, high speed program/erase (1 μs/0.1ms), long retention time greater than 108s for 10⁸s charge loss, excellent endurance after 10⁶ P/E cycles, negligible read/write disturbances and multi-bit operation.