High performance multi-bit nonvolatile HfO/sub 2/ nanocrystal memory using spinodal phase separation of hafnium silicate

Abstract

In this paper, we exploit a novel technique for preparing high density HfO/sub 2/ nanocrystals with an average size > 10nm using spinodal phase separation of Hf-silicate thin film by 900/spl deg/C rapid thermal annealing for nonvolatile memories. The density can be as high as 0.9/spl sim/1.9/spl times/10/sup 12/cm/sup -2/. Owing to the fact that HfO/sub 2/ nanocrystals are well embedded inside SiO/sub 2/ 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 /spl mu/s/0.1ms), long retention time greater than 108s for 10/sup 8/s charge loss, excellent endurance after 10/sup 6/ P/E cycles, negligible read/write disturbances and multi-bit operation.