Sb-Se-based electrical switching device with fast transition speed and minimized performance degradation due to stable mid-gap states

Abstract

Chalcogenide glass has a unique volatile transition between high- and low-resistance states under an electric field, a phenomenon termed ovonic threshold switching (OTS). This characteristic is extensively utilized in various electronic memory and computational devices, particularly as selectors for cross-point memory architectures. Despite its advantages, the material is susceptible to glass relaxation, which can result in substantial drifts in threshold voltage and a decline in off-current performance over successive operational cycles or long storage time. In this study, we introduce an OTS device made from stoichiometric Sb₂Se₃ glass, which retains an octahedral local structure within its amorphous matrix. This innovative material exhibits outstanding OTS capabilities, maintaining minimal degradation despite undergoing over 10⁷ operating cycles. Via comprehensive first-principles calculations, our findings indicate that the mid-gap states in amorphous Sb₂Se₃ predominantly stem from the atomic chains characterized by heteropolar Sb-Se bonds. These bonds exhibit remarkable stability, showing minimal alteration over time, thereby contributing to the overall durability and consistent performance of the material. Our findings not only shed light on the complex physical origins that govern the OTS behavior but also lay the groundwork for creating or optimizing innovative electrical switching materials.