Simultaneously low resistance drift and ultra-fast phase change speed based on GeSb/Sb multilayer thin films

Thermal stability and phase transition rate are two important issues that restrict the engineering applications of phase change memories. In this paper, GeSb/Sb multilayer films were prepared by multilayer stacking, and their phase transition properties were investigated. GeSb/Sb multilayer films had higher crystallization temperature, better data retention, and lower resistance drift than pure Sb films, which indicated that they had excellent thermal stability and accuracy of resistance identification. The test results of X-ray diffraction and atomic force microscopy showed that GeSb spacer layers could inhibit grain growth of Sb film layers, thus reducing the roughness and potential fluctuation of the film surface. X-ray reflectivity experiments showed that the GeSb/Sb multilayer films before and after crystallization had small volume changes. The devices based on [GeSb(7 nm)/Sb(3 nm)]8 multilayer films could achieve reversible resistive transition operation between SET and RESET at a pulse width of 10 ns, showing satisfactory transition rate and operational power consumption. The low resistance drift and ultra-fast phase transition speed make GeSb/Sb multilayer films one of the promising choices for phase change memories.