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 (Tc) and the sheet resistance increased in both the amorphous and crystalline states. In contrast, the melting temperature (Tm) 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.