Effect of selenium doping on the crystallization behaviors of GeSb for phase-change memory applications

We investigated the effect of Se doping on the physical and electrical properties of Ge₁₀Sb₉₀ films prepared by sputtering. We examined the crystal structure, chemical bonding, electrical and thermal properties, and volume shrinkage during the crystallization of Ge₁₀Sb₉₀ films doped concentrations of Se between 0 and 20 at.%. X-ray diffraction patterns showed that incorporating Se leads to phase separation at high Se concentrations. As the Se concentration increased, both the crystallization temperature (T_c) and the sheet resistance increased in both the amorphous and crystalline states. In contrast, the melting temperature (T_m) and grain size both decreased with the increasing Se. The volume shrinkage of the Se-doped Ge₁₀Sb₉₀ films was analyzed by X-ray reflectivity measurements. Our results demonstrate that Se-doped Ge₁₀Sb₉₀ films show a favorably low operation current and good thermal and mechanical stability, which strongly indicate their feasibility for phase-change memory applications.