Improving the selector characteristics of ovonic threshold switch via UV treatment process

Abstract

In this study, we investigated the influence of ultraviolet (UV) treatment on the ovonic threshold switch (OTS) to improve its selector properties. Our findings demonstrate that iteratively applying UV treatment during the film deposition phase considerably improves device characteristics compared to a single UV treatment. Consequently, this process provided a significant decrease in the forming voltage, maintaining outstanding switching features, with an off-state current of approximately 2 nA. Furthermore, the refined UV treatment process resulted in an impressive 45% improvement in threshold voltage drift characteristics and facilitated excellent switching uniformity. X-ray photoelectron spectroscopy analysis revealed alterations in the bonding structure of the Si-Te-As-Ge film after UV exposure. Specifically, a transition was observed from unstable homopolar bonds, such as As-As or Te-Te, to their more stable heteropolar equivalents, such as As-Te. These results highlight the potential of UV treatment as an effective method for enhancing the OTS performance.