Improved thermal stability and contact of antimony film by the interlayer HfO2

Abstract

The thermal stability was one of the primary obstacles hindering the development of phase-change memory. In this paper, Sb/HfO2 multilayer phase-change films were prepared by multilayer composite method. The transition process of Sb/HfO2 multilayer films from amorphous to crystalline state was studied by in-situ heating. With the decrease of the thickness of Sb layer, the crystallization temperature of Sb/HfO2 increased significantly. At the same time, the data retention temperature for 10 years increased from 14 °C of pure antimony to 147 °C of Sb/HfO2. The bandgap became wider and the surface became smoother. The existence of a large number of Sb microcrystals inhibited the phase transformation process. Compared with single-layer Sb film, Sb/HfO2 multilayer film had smaller volume change before and after phase transformation. The results showed that the addition of HfO2 interlayer significantly enhanced the amorphous thermal stability of Sb and improved the effective contact between the phase-change layer and the electrode. Sb/HfO2 multilayer film was a potential phase-change film with high stability and good reliability.