We measure power dissipation in phase change memory (PCM) devices by scanning Joule expansion microscopy (SJEM) with ∼50 nm spatial and 0.2 K temperature resolution. The temperature rise in the Ge2Sb 2Te5 (GST) is dominated by Joule heating, but at the GST-TiW contacts it is a combination of Peltier and current crowding effects. Comparison of SJEM and electrical measurements with simulations of the PCM devices uncovers a thermopower of ∼350 μV K-1 and a contact resistance of ∼2.0 × 10-8 Ω m2 (to TiW) for 25 nm thick films of face centered-cubic crystalline GST. Knowledge of such nanometer-scale Joule, Peltier, and current crowding effects is essential for energy-efficient design of future PCM technology.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)