Advanced interfacial phase change material: structurally confined and interfacially extended superlattice

TL;DR

This paper introduces an advanced interfacial phase change memory (iPCM) using a GeTe/Ti-Sb2Te3 superlattice, which reduces power consumption and enhances performance through structural confinement and interfacial engineering.

Contribution

It demonstrates the synthesis and analysis of a Ti-doped Sb2Te3 superlattice that improves phase change properties and enables multi-level states for neuromorphic memory applications.

Findings

Reduced switching energy due to effective thermal barriers.

Enhanced cycling endurance and write speed/energy.

Achievement of multi-level states for neuromorphic memory.

Abstract

Interfacial Phase Change Memory (iPCM) retrench unnecessary power consumption due to wasted heat generated during phase change by reducing unnecessary entropic loss. In this study, an advanced iPCM (GeTe/Ti-Sb2Te3 Superlattice) is synthesized by doping Ti into Sb2Te3. Structural analysis and density functional theory (DFT) calculations confirm that bonding distortion and structurally well-confined layers contribute to improve phase change properties in iPCM. Ti-Sb2Te3 acts as an effective thermal barrier to localize the generated heat inside active region, which leads to reduction of switching energy. Since Ge-Te bonds adjacent to short and strong Ti-Te bonds are more elongated than the bonds near Sb-Te, it is easier for Ge atoms to break the bond with Te due to strengthened Peierls distortions (Rlong/Rshort) during phase change process. Properties of advanced iPCM (cycling endurance, write speed/energy) exceed previous records. Moreover, well-confined multi-level states are obtained with advanced iPCM, showing potential as a neuromorphic memory. Our work paves the way for designing superlattice based PCM by controlling confinement layers.