Thermal Confinement by Monolayer MoS₂ for Reduced RESET Current in Phase Change Memory Pillar Cells

Abstract

Phase change memory (PCM) is one of the most promising nonvolatile memory technologies for high-density, highendurance, fast-switching, and multilevel data storage. However, the high RESET current requirement remains a critical bottleneck in the development of PCM technology. In this work, we propose a pillar-shaped PCM device that consists of a Ge 2 Sb 2 Te 5 (GST) layer sandwiched between the top and the bottom TiN electrodes. An atomically thin layer of MoS 2 is grown on top of the oxidized bottom TiN layer. A filament formed through the TiO 2 and MoS 2 layers enables electrical conduction, while the high thermal resistivity of MoS 2 ensures excellent thermal confinement within the GST layer. Finite element simulations show a 91% reduction in RESET current brought about by the filament, while the use of MoS 2 yields a further ∼30% decrease in the switching power. The results presented here demonstrate the potential use of two-dimensional (2D) materials with conventional PCM cells to reduce switching power.