High thermal stability Sb3Te-TiN2 material for phase change memory application

For phase change memory (PCM) applications, it has been widely accepted that delta phase Sb-Te has fast operation speed and good phase stability. However, the fast growth crystallization mechanism will cause poor amorphous phase stability and overlarge grain size. We introduce TiN2 into delta phase Sb-Te (Sb3Te) to enhance the amorphous thermal stability and refine the grain size. With TiN2 incorporating, the temperature for 10-year data retention increases from 79 degrees C to 124 degrees C. And the grain size decreases to dozens of nanometers scale. Based on X-ray photoelectron spectroscopy and transmission electron microscopy results, we knew that nitrogen atoms bond with titanium, forming disorder region at the grain boundary of Sb3Te-TiN2 (STTN). Thus, STTN has a quite different crystallization mechanism from Sb3Te. Furthermore, PCM device based on STTN can realize reversible phase change under 20 ns electrical pulse. (C) 2015 AIP Publishing LLC.