Dual-Scale Confinement in TiTe₂/C-Sb₃Te Multilayers Enables Ultralow Density Variation and High Uniformity for...

Phase-change memory (PCM) is limited by the intrinsic trade-off among grain growth, density variation, and device uniformity. Here, a TiTe₂/C-Sb₃Te multilayer nanostructure was developed to enable three-dimensional confinement of phase transition. By synergistically integrating carbon-induced bond stiffening with TiTe₂ interlayer confinement, nanoscale grains (∼10 nm) are effectively stabilized, leading to an ultralow density variation of 1.01%. This material-structure co-design strategy results in a comprehensive performance improvement, including a fast switching speed of 5 ns, low RESET energy of 6.2 pJ, and an ultralow resistance drift coefficient of 0.0019, together with stable endurance over 10⁶ cycles. Notably, significantly improved resistance distribution and switching uniformity are achieved across multiple devices. The enhanced performance originates from suppressed atomic diffusion via robust C-C chains and inhibited vertical grain growth by TiTe₂ barriers. This work establishes a general strategy for coupling chemical bonding modulation with structural confinement, offering a scalable pathway toward high-performance and reliable PCM.