Temperature-dependent thermal conductivity and interfacial resistance of Ge-rich Ge${}_2$Sb${}_2$Te${}_5$ films and multilayers

This article reports on the thermal characterization of Ge-rich Ge${}_2$Sb${}_2$Te${}_5$ films and Ge${}_2$Sb${}_2$Te${}_5$/Ge-rich Ge${}_2$Sb${}_2$Te${}_5$ multilayers designed for high-temperature applications in the field of phase-change memory. The thermal conductivities of such materials and the thermal boundary resistance with the Si${}_3$N${}_4$ dielectric material are characterized by two different photothermal techniques. The phase change in Ge-rich Ge${}_2$Sb${}_2$Te${}_5$ is found to occur at a temperature higher than that of the Ge${}_2$Sb${}_2$Te${}_5$ alloy. The Ge${}_2$Sb${}_2$Te${}_5$/Ge rich Ge${}_2$Sb${}_2$Te${}_5$ multilayer has been observed to feature two phase changes corresponding to Ge-rich Ge${}_2$Sb${}_2$Te${}_5$ and Ge${}_2$Sb${}_2$Te${}_5$. Finally, it is estimated that the thermal resistance of the interface separating Ge-rich Ge${}_2$Sb${}_2$Te${}_5$ and Ge${}_2$Sb${}_2$Te${}_5$ nanolayers constitutes the multilayer structure and its contribution has been realized to be significant in enhancing the thermal resistance of the multilayer structure. (© 2022 Wiley‐VCH GmbH)