Leakage Current Optimization Based on Conduction Paths Modulation by Interfacial Layer in Ge-Te OTS Selector

Ovonic threshold switch (OTS) selector plays an important role in suppressing the leakage current in 3D phase change memory. In this work, we optimized the OTS selector by applying an interfacial layer and proposed that the reduction of conduction paths explains how the interfacial layer affects the leakage current. The leakage current decreased by 120nA after applying the interfacial layer. The OTS selector with an interfacial layer maintains the same level of electrical performance in terms of speed and endurance. The devices show fast speed (6 ns) and good endurance (10⁹). Through the comparative analysis of the leakage current, ON-state current, and drift characteristic, the results all illustrate the conduction paths reduction. From the activation energy extracted by Poole-Frenkel fitting, we found that the interfacial layer introduced a barrier into the selector. Considering the area dependence of the leakage current, we proposed that the reduction in leakage current was due to the reduction in conduction paths. This work contributes to the improvement of the performance of the OTS selector and provides a way to suppress leakage current in the OTS selector.