Outstanding Improvement in 4Kb Phase-Change Memory of Programming and Retention Performances by Enhanced Thermal Confinement

In this paper we present the optimization of the thermal confinement of a heater-based Phase-Change Memory (PCM) integrating a Ge-rich Ge-Sb-Te alloy (GGST) by the engineering of the encapsulation dielectric layer. Lower thermal conductivity of a SiC-based encapsulation layer wrt SiN, is demonstrated to improve the thermal confinement during programming operations in the PCM cell. Thanks to electrical characterization of 4Kb PCM arrays, we investigate the performance of thermally improved PCM devices, showing higher programming efficiency, higher SET programming speed and data retention higher than 250°C. The results are supported by 3D electro-thermal simulations, highlighting the effects of the higher thermal confinement achieved. These results confirm the outstanding improvement of the performances achievable in state-of-the-art PCM thanks to the thermal engineering of the cell.