Thermal resistance at Al-Ge₂Sb₂Te₅ interface

$Ge2Sb2Te5$ is a phase change material candidate to constitute the active element of future nonvolatile memory devices. The evolution of the thermal resistance at the interface between an aluminum thin layer and $Ge2Sb2Te5$ is studied using the time resolved pump probe technique from room temperature to 400 °C. The thermal resistance is influenced by the amorphous to crystalline phase change occurring in $Ge2Sb2Te5$⁠. The decrease in the thermal resistance from the amorphous to the crystalline phase is well explained by the diffuse mismatch model asymptotic form for high temperature. The large increase of the interface thermal resistance between fcc and hcp crystalline states is explained by the fast and significant grain growth and species inter-diffusion during this second phase change. This leads to the formation of an interfacial layer whose chemical and mechanical intrinsic properties have been measured in order to model the thermal resistance in the hcp state.