Development of Sb2Se3 alloys by Ti-doping with ultralow resistance drift and improved microstructure for nonvolatile memory applications

Abstract

The Sb2Se3 and Ti-doped Sb2Se3 phase change thin films were prepared by magnetron sputtering. The relationship between resistance drift and crystallization behavior of Sb2Se3 and Ti-doped Sb2Se3 thin films were thoroughly investigated. The results revealed that when Ti-doping concentration reaches 5.4 at. %, Ti5.4(Sb2Se3)95.4 thin film exhibited a high thermal stability with crystallization temperature of 225 °C and 10-year data retention temperature of 129.5 °C. This benefits to lower resistance drift coefficient from 0.067 for Sb2Se3 to 0.002 for Ti5.4(Sb2Se3)95.4. Further microstructural analysis revealed the suppression of large grain growth in Ti-doped Sb2Se3 thin films, while the formation of Ti–Sb and Ti–Se bonds being responsible for enhanced stability of the amorphous Ti-doped thin films. Moreover, the Ti doping promoted one-dimensional growth-dominated crystallization mechanism of the studied alloys, leading to the reduced nucleation index compared to Sb2Se3. The present study sheds valuable light on the effectively reducing nucleation randomness in chalcogenide-based phase-change materials.