High Temperature Thermal Characterization of Ge₂Sb₂Te₅ for Phase Change Memory

We propose a novel design of Joule heating thermometry to measure thermal properties of Ge₂Sb₂Te₅ (GST) films at temperatures relevant for the switching of phase change memory devices. Vertically stacked micro-fabricated heaters control temperature and measure thermal conductivity of thin films using the 3ω method. The thermal time constant of the experimental structure enables studies of short time scale crystallization and cycling effects for phase change materials. This work reports the thermal conductivity of GST films from the room temperature to above 400 Celsius in amorphous, face-centered cubic, and hexagonal close-packed phases.