Temperature‐Dependent Thermal Conductivity and Interfacial Resistance of Ge‐Rich Ge2Sb2Te5 Films and Multilayers

Abstract

This article reports on the thermal characterization of Ge‐rich Ge2Sb2Te5 films and Ge2Sb2Te5/Ge‐rich Ge2Sb2Te5 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 Si3N4 dielectric material are characterized by two different photothermal techniques. The phase change in Ge‐rich Ge2Sb2Te5 is found to occur at a temperature higher than that of the Ge2Sb2Te5 alloy. The Ge2Sb2Te5/Ge rich Ge2Sb2Te5 multilayer has been observed to feature two phase changes corresponding to Ge‐rich Ge2Sb2Te5 and Ge2Sb2Te5. Finally, it is estimated that the thermal resistance of the interface separating Ge‐rich Ge2Sb2Te5 and Ge2Sb2Te5 nanolayers constitutes the multilayer structure and its contribution has been realized to be significant in enhancing the thermal resistance of the multilayer structure.