Thermal stability improvement of Sb-Si3N4 composite phase-change film by tunning crystallization mechanism

Abstract

Phase change materials (PCMs) are of great importance for universal storage to transform the existing Von-Neumann computing system architecture and artificial intelligence neuron system. The pure Sb film has attracted great attention among PCMs due to its lower melting point and faster crystallization speed. The unstable nature in amorphous state severely limits its application in nonvolatile universal storage. Here we combine Sb with Si3N4 to tune its crystallization mode and consequently improve its thermal stability. It is found that stable Si3N4 can degrade the long-range order and suppress the nano-size growth of grain Sb. With the addition of Si3N4, the nano-growth spacing of Sb crystallite is compressed, and Si3N4 encapsulates the Sb in a physically wrapped morphology. The tunable crystallization mode induced by such unique loculated microstructure contributes to the obvious improvement of thermal stability of Sb film. These results pave the way to explore novel PCMs, as well as to engineer traditional PCMs such as Ge-Sb-Te for building high-stability universal storage.