Ultralow-Power Programmable 3D Vertical Phase-Change Memory with Heater-All-Around Configuration.

Abstract

Recent advancements in phase-change memory (PCM) technology have predominantly stemmed from material-level designs, which have led to fast and durable device performances. However, there remains a pressing need to address the enormous energy consumption through device-level electrothermal solutions. Thus, the concept of a 3D heater-all-around (HAA) PCM fabricated along the vertical nanoscale hole of dielectric/metal/dielectric stacks is proposed. The embedded thin metallic heater completely encircles the phase-change material, so it promotes highly localized Joule heating with minimal loss. Hence, a low RESET current density of 6-8 MA cm^-2 and operation energy of 150-200 pJ are achieved even for a sizable hole diameter of 300 nm. Beyond the conventional 2D scaling of the bottom electrode contact, it accordingly enhances ≈80% of operational energy efficiency compared to planar PCM with an identical contact area. In addition, reliable memory operations of ≈10⁵ cycles and the 3-bits-per-cell multilevel storage despite ultrathin (<10 nm) sidewall deposition of Ge₂Sb₂Te₅ are optimized. The proposed 3D-scaled HAA-PCM architecture holds promise as a universally applicable backbone for emerging phase-change chalcogenides toward high-density, ultralow-power computing units.