Reliable impurity trap memory with high charge trap efficiency using ultrathin SiO2 impurity host layer for nonvolatile memory application

We demonstrated reliable impurity trap memory (ITM) with high charge trap efficiency by incorporating only 1nm-SiO"2 impurity host layer (IHL) between Al"2O"3 diffusion barrier layer and blocking oxide. While the ITM without IHL showed significant retention degradation as the amount of Ti impurity increased from 0.7 to 3A for enlarging memory window, the ITM with IHL showed stable retention characteristic which is charge loss less than 1V after 10^4s at 85^oC. We postulated that the chemical reaction between Ti and SiO"2 induced three dimensionally-distributed impurity traps in IHL, which could result in the well-discrete stored charges in program mode.