Thermoelectric Characterization of Ge₂Sb₂Te₅ Films for Phase-Change Memory

While thermoelectric effects can strongly influence the performance of phase-change memory (PCM), the thermoelectric properties of phase-change materials for thin film structure have received little attention. This work reports the temperature and phase dependent Seebeck coefficient of 25 nm and 125 nm thick Ge₂Sb₂Te₅ (GST) films. The Seebeck coefficient of crystalline GST films varies strongly with film thickness, due to changes in crystallization effect and grain boundary scattering. Electrothermal simulations demonstrate that the measured thermoelectric properties can strongly influence the temperature distribution and figures of merit for PCM devices. These data will facilitate cell optimization of novel phase-change memories.