Uncovering Thermal and Electrical Properties of Sb2Te3/GeTe Superlattice Films

Abstract

Superlattice-like phase change memory (SL-PCM) promises lower switching current than conventional PCM based on Ge2Sb2Te5 (GST). However, a fundamental understanding of SL-PCM requires detailed characterization of the interfaces within such a SL. Here, we explore the electrical and thermal transport of SLs with deposited Sb2Te3 and GeTe alternating layers of various thicknesses. We find up to ~4X reduction of the effective cross-plane thermal conductivity of the SL stack (as-deposited polycrystalline) compared to polycrystalline GST (as-deposited amorphous and later annealed) due to the thermal interface resistances within the SL. Thermal measurements with varying periods of our SLs show a signature of phonon coherence with a transition from wave-like to particle-like phonon transport, further described by our modeling. Electrical resistivity measurements of such SLs reveal strong anisotropy (~2000X) between the in-plane and cross-plane directions due to the weakly interacting van der Waals gaps. This work uncovers electro-thermal transport in SLs based on Sb2Te3 and GeTe, for improved design of low-power PCM.

References in corpus (6)

• Interface controlled thermal properties of ultra-thin chalcogenide-based phase change memory devices
• Quasi-ballistic thermal transport across MoS${}_2$ thin films
• Thermoelectric transport in ${\text{Bi}}_2{\text{Te}}_3/{\text{Sb}}_2{\text{Te}}_3$ superlattices
• Engineering Thermal and Electrical Interface Properties of Phase Change Memory with Monolayer MoS2
• Anomalous thermal expansion of Sb${}_2$Te${}_3$ topological insulator
• Coherent phonon study of (GeTe)${}_l$(Sb${}_2$Te${}_3$)${}_m$ interfacial phase change memory materials

Cited by in corpus (4)

• Conversion between metavalent and covalent bond in metastable superlattices composed of 2D and 3D sublayers
• Electronic and Thermal Properties of ${\text{GeTe/Sb}}_2{\text{Te}}_3$ Superlattices by ab-initio Approach: Impact of Van der Waals Gaps on Vertical Lattice Thermal Conductivity
• Lateral Transport and Field-Effect Characteristics of Sputtered P-Type Chalcogenide Thin Films
• Internal reverse-biased p-n junctions: a possible origin of the high resistance in phase change superlattice