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

Phase change memory (PCM) is one of the most promising nonvolatile memory technologies for high-density, high-endurance, 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 Ge₂Sb₂Te₅ (GST) layer sandwiched between the top and the bottom TiN electrodes. An atomically thin layer of MoS₂ is grown on top of the oxidized bottom TiN layer. A filament formed through the TiO₂ and MoS₂ layers enables electrical conduction, while the high thermal resistivity of MoS₂ 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 MoS₂ 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.