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, 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.