The coupling effect and phase transition behavior of multiple interfaces in GeTe/Sb superlattice-like films

Abstract

In this paper, the phase transition mechanism and device conversion performance of the Sb/GeTe superlattice-like films were studied and showed improved amorphous thermal stability and resistance drift compared to the pure Sb films. Transmission electron microscopy showed that the Sb layer plays a leading role in the crystallization process, forming a large number of Sb grains. The metallic behavior of the Sb/GeTe thin films was confirmed by density functional theory calculations. The thermal conductivity of the crystalline film was found to be higher than that of the amorphous film, and the thermal conductivity of the Sb/GeTe film was lower than that of the other monolayer films. In the Sb/GeTe film, the Sb–Sb and Ge–Te bonds were the main bond structures, and some Sb–Te bonds were formed at the layer interfaces, enhancing the stability of the film. Laser picosecond measurements showed that Sb/GeTe film had a higher crystallization rate than the GeTe film. The phase change memory devices based on the Sb/GeTe thin films were found to have lower operational power consumption and higher transition speed. These results showed that the Sb/GeTe thin film explored in this study was a promising phase change storage thin film with excellent performance.