Thermal boundary resistance at Ge2Sb2Te5/ZnS:SiO2 interface

The thermal conductivity of sputtered amorphous-Ge2Sb2Te5 (a-GST)/ZnS:SiO2 and crystalline-Ge2Sb2Te5 (c-GST)/ZnS:SiO2 multilayer films has been measured in the temperature range between 50 and 300 K using the 3ω method. The conductivity data in the direction of the cross plane of the films showed lower values than the series conductance of the constituent layers, which was calculated from the thermal conductivity of thick a-GST, c-GST, and ZnS:SiO2 films measured independently. From the reduction in the multilayer thermal conductivity, the thermal boundary resistance at the interface between GST and ZnS:SiO2 films was calculated. The boundary resistance in the c-GST multilayer was lower than that for the a-GST case in the whole measured temperature region.