High temperature electrical resistivity and Seebeck coefficient of Ge \textlesssub\textgreater2\textless/sub\textgreater Sb \textlesssub\textgreater2\textless/sub\textgreater Te \textlesssub\textgreater5\textless/sub\textgreater thin films
Journal of Applied Physics, 122 (12):
125104 (сентября 2017)DOI: 10.1063/1.4996218
Аннотация
High-temperature characterization of the thermoelectric properties of chalcogenide Ge2Sb2Te5 (GST) is critical for phase change memory devices, which utilize self-heating to quickly switch between amorphous and crystalline states and experience significant thermoelectric effects. In this work, the electrical resistivity and Seebeck coefficient are measured simultaneously as a function of temperature, from room temperature to 600 °C, on 50 nm and 200 nm GST thin films deposited on silicon dioxide. Multiple heating and cooling cycles with increasingly maximum temperature allow temperature-dependent characterization of the material at each crystalline state; this is in contrast to continuous measurements which return the combined effects of the temperature dependence and changes in the material. The results show p-type conduction (S \textgreater 0), linear S(T), and a positive Thomson coefficient (dS/dT) up to melting temperature. The results also reveal an interesting linearity between dS/dT and the conduction activat...