Electro-Thermal Confinement Enables Improved Superlattice Phase Change Memory

Abstract

Large switching current density and resistance drift remain challenges for phase change memory (PCM) in data storage and neuromorphic computing applications. Here, we address these by electro-thermal and structural confinement in a GeTe/Sb₂Te₃ superlattice PCM (SL-PCM) with thermally-induced phase change, while observing scalability with bottom electrode diameter. We demonstrate &#x007E;<inline-formula> <tex-math notation="LaTeX">$\text{8-10}\times $ </tex-math></inline-formula> reduction of reset current density <inline-formula> <tex-math notation="LaTeX">$({J}_{\text {reset}})$ </tex-math></inline-formula> and &#x007E;<inline-formula> <tex-math notation="LaTeX">$\text{25-30}\times $ </tex-math></inline-formula> reduction of power <inline-formula> <tex-math notation="LaTeX">$({P}_{\text {reset}})$ </tex-math></inline-formula> in our mushroom cell SL-PCM compared to control Ge₂Sb₂Te₅ (GST) PCM with the same device structure. The SL-PCM devices also exhibit multi-level states with <inline-formula> <tex-math notation="LaTeX">$\sim 10\times $ </tex-math></inline-formula> lower resistance drift compared to control GST PCM. Material characterization and electro-thermal simulations confirm the role of heat confinement in SL-PCM, paving the way towards low-power, high-density memory and data storage.