The micro-structure and composition evolution of Ti-Sb-Te alloy during reversible phase transition in phase change memory

We contrastively investigate the micro-structure and composition evolution of Ti0.53Sb2Te2.6 (TST) alloy in phase change memory cells respectively undergoing three repeated and 105 endurance operations. For the cell experiencing three repeated operations, the active phase change region is not formed while many small crystal grains are found in TST/W interfaces, and the composition of TST in phase change region is almost unchanged. However, for another cell going through endurance operation, the active region is clearly observed in TST layer with abnormally large residual grains, which are found in Ti-rich and Sb, Te-deficient composition.