Thermal characterization of the SiO2 -Ge2Sb2Te5 interface from room temperature up to 400 °C

The thermal conductivity of Ge2Sb2Te5 GST layers, as well as the thermal boundary resistance at the interface between the GST and amorphous SiO2, was measured using a photothermal radiometry experiment. The two phase changes in the Ge2Sb2Te5 were retrieved, starting from the amorphous and sweeping to the face centered cubic fcc crystalline state at 130 °C and then to the hexagonal crystalline phase hcp at 310 °C. The thermal conductivity resulted to be constant in the amorphous phase, whereas it evolved between the two crystalline states. The thermal boundary resistance at the GST-SiO2 interface was estimated to be higher for the hcp phase than for the amorphous and fcc ones.