Threshold Switching Behavior and Underlying Mechanisms in Pure SiO₂-Based Selectors

In high-density crossbar array memory architectures, selector devices play a crucial role in suppressing sneak-path currents and ensuring stable operation. In this study, we propose a pure SiO₂-based selector fabricated using conventional semiconductor processes and materials and experimentally demonstrate its threshold switching (TS) characteristics. Stable TS behavior is verified with an endurance exceeding 10⁹ cycles under repeatable measurement sequences and pulse-driven operations. Interface structure analysis combined with controlled pulse-based electrical characterization reveals that the formation of oxygen vacancies (V_Os), the resulting structural asymmetry, and the dynamic charging behavior of V_Os within the oxide are the key mechanisms governing the TS manifestation. Based on these insights, the optimized pulse conditions are established for reliable TS operation. The proposed selector, featuring a simple undoped oxide structure, can be fabricated at temperatures below 300 °C and offers tunable threshold voltage, enabling excellent integration compatibility with advanced memory devices. This study introduces a selector structure that distinguishes itself from conventional chalcogenide- or metal-oxide-based selectors by combining superior process and device compatibility with structural simplicity, offering a promising pathway toward a highly integrated and CMOS-compatible selector.