In this study, the amorphous-to-crystalline transitions of superlattice-like (SLL) Zn₁₅Sb₈₅/Ga₃₀Sb₇₀ thin films were investigated by in situ film resistance measurement. The thermal stability, resistance and band gap of the SLL Zn₁₅Sb₈₅/Ga₃₀Sb₇₀ thin film perform well. The data retention temperature for 10 years increases from 177°C of [Zn₁₅Sb₈₅7/Ga₃₀Sb₇₀3] to 220°C of [Zn₁₅Sb₈₅2/Ga₃₀Sb₇₀8]. The X-ray diffraction patterns show the presence of a large amount of Sb phase in the Zn₁₅Sb₈₅/Ga₃₀Sb₇₀ thin films, which causes a rapid phase transition. The surface morphology is observed by atomic force microscopy, which indicates that the thickness of Ga₃₀Sb₇₀ in the SLL thin films can affect the grain size and inhibit the crystallisation process. For the Zn₁₅Sb₈₅/Ga₃₀Sb₇₀ thin films, an ultra-short switching time of around 2 ns is achieved. These results indicate that the SLL Zn₁₅Sb₈₅/Ga₃₀Sb₇₀ thin films have a promised application in phase change memory.