Influence of samarium modification on the phase-change performance and phase structure of tin antimonide

This work presents the optimization of the crystallization behavior and reliability of Sn₁₅Sb₈₅thin films by doping Sm element. The phase transition behaviors induced by thermal were investigated byin situresistance measurement. With the addition of Sm element, Sn₁₅Sb₈₅film exhibits the superior crystallization temperature (232 °C) and data conservation (172.32 °C for 10 years), larger activation energy of crystallization (4.91 eV) and crystalline resistance (∼10³Ω), which contributes to the increased thermal stability of the amorphous state and decrease in the programming energy. The Sm-doping can broaden the energy band gap from 0.55 to 1.07 eV. The amorphous Sm and Sn compositions could retard grain growth and refine grain size from 21.13 to 11.13 nm, combining with x-ray diffraction and x-ray photoelectron spectroscopy. The surface morphology of Sn₁₅Sb₈₅film becomes smoother after Sm doping as determined by atomic force microscopy images, resulting in the improved interfacial reliability. Phase change memory devices based on Sm_0.095(Sn₁₅Sb₈₅)_0.905films can successfully achieve the complete SET and RESET reversible operation process with high operating speed (200 ns) and low power consumption (1.6 × 10^-10J). The results suggest that doping the proper concentration of Sm element will be an effectual solution to adapt and optimize the crystallization properties of Sn₁₅Sb₈₅phase change material.