Thickness and stoichiometry dependence of the thermal conductivity of GeSbTe films

Thermal conduction in GeSbTe films strongly influences the writing energy and time for phase change memory (PCM) technology. This study measures the thermal conductivity of Ge2Sb2Te5 between 25 and 340°C for layers with thicknesses near 60, 120, and 350nm. A strong thickness dependence of the thermal conductivity is attributed to a combination of thermal boundary resistance (TBR) and microstructural imperfections. Stoichiometric variations significantly alter the phase transition temperatures but do not strongly impact the thermal conductivity at a given temperature. This work makes progress on extracting the TBR for Ge2Sb2Te5 films, which is a critical unknown parameter for PCM simulations.