Effect of a thin Ti interfacial layer on the thermal resistance of Ge2Sb2Te5-TiN stack

We study the dependence of the thermal resistance of TiN/Ge2Sb2Te5 stacks on Si in the presence or not of a thin Ti interfacial layer. While for TiN/Ge2Sb2Te5 almost ideal thermal properties of the interfaces are found, a different behaviour is measured for TiN/Ti/Ge2Sb2Te5. After exposure to temperatures up to 440 C, the thermal resistance results to be lower than expected despite both the formation of the TiTe2 phase, the depletion of Te inside Ge2Sb2Te5, and the non complete development of the hexagonal structure. Those observations have been also validated on the SiO2/Ge2Sb2Te5 stack with and without Ti interfacial layer.