Controllable single phase enables superior thermal stability in Sb-Sn-S films

Abstract

Sb-Sn-S thin films were prepared by magnetron sputtering, and the effects of the SnS content on the macroscopic performance and microstructure of Sb were investigated. Results show that Sb55(SnS)45 exhibited the best performance, with a crystallization temperature of 210 °C, solving the issue of spontaneous Sb crystallization. However, the thermal stability of Sb37(SnS)63 film could no longer be significantly improved. The investigated crystallization mode revealed that Sb55(SnS)45 exhibited a growth-dominated crystallization behavior, maintaining a high crystallization rate while substantially improving the thermal stability. In terms of the microstructure, high-energy Sb–S and Sb–Sn bonds were formed, breaking the originally unstable Sb–Sb bonds. In the case of Sb37(SnS)63, the internal Sb–S and Sb–Sn bonding environment reached a saturation state, and the excessive introduction of SnS resulted in the stacking arrangement of the Sb–Sn–S amorphous alloy, leading to lattice distortion. However, an appropriate amount of Sb–Sn–S amorphous alloy polymerized around the SbSn grains, limiting the grain growth and the element segregation, thereby enhancing the long-term stability of the phase-change thin film.