Direct Observation of Conduction Mechanism in Te-Based Selector-Only Memory via Low-Frequency Noise Characterization.
basic_science · Level V
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- Record sourced from PubMed, PMID 42273773.
- Also identified by DOI 10.1021/acs.nanolett.6c00362.
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Abstract
Selector-only memory (SOM) based on ovonic threshold switches is a promising candidate for dense cross-point memory by integrating selector and memory functions in a single two-terminal device. However, the physical origins of off-state conduction and threshold voltage (<i>V</i><sub>th</sub>) modulation remain unclear. Here, we investigate these mechanisms in a Te-rich Ge-Sb-Se-Te:Sn SOM by correlating DC transport, low-frequency noise (LFN), and materials analyses. DC <i>I</i>-<i>V</i> characteristics analyzed using Poole-Frenkel (PF) emission and trap-assisted tunneling (TAT) models reveal identical trap energy levels across prefirst firing, low-<i>V</i><sub>th</sub>, and high-<i>V</i><sub>th</sub> states, indicating a common trap species with state-dependent spatial redistribution. LFN measurements distinguish PF- and TAT-dominated regimes and show consistent state-dependent noise behavior. Cross-sectional energy-dispersive X-ray spectroscopy reveals electric-field-polarity-dependent Te redistribution near the top electrode, while ab initio calculations identify Te-Te dimer defects as acceptor-like deep traps governing off-state conduction. These results provide a unified mechanism for <i>V</i><sub>th</sub> modulation in Te-based SOM devices.