Energy-Efficient Phase-Change Memory Disc-Type Cells Leveraging Ultrathin Phase-Change Films

While phase change memory (PCM) is one of the most mature resistive memory technologies, innovations are still needed to reduce the relatively high programming current. At a structural level, PCM cell designs attempt to reduce this write energy by either minimizing the contact area of one electrode (e.g., mushroom cell) or by minimizing the phase-change material volume (e.g., bridge/line cell), but it has been challenging to continue to scale these techniques while maintaining manufacturability. Here, we introduce a PCM disc-type cell that accomplishes both volume minimization using an ultra-thin phase-change material and contact area minimization using the heater of a mushroom cell. Using finite-element method simulation and experimental validation, we show that this disc-type PCM cell offers superior programming performance, conductance tunability, and improved retention characteristics. This novel PCM device architecture provides a platform to further engineer electrical characteristics and leverage the unique properties of ultrathin phase-change material films, making it a promising candidate for emerging applications such as analog in-memory computing.