Microscopic Origin of Polarity-Dependent V_TH Shift in Amorphous Chalcogenides for 3D Self-Selecting Memory

Ovonic threshold switching (OTS) selectors based on amorphous chalcogenides can revolutionize 3D memory technology owing to their self-selecting memory (SSM) behavior. However, the complex mechanism governing the memory writing operation limits compositional and device optimization. This study investigates the mechanism behind the polarity-dependent threshold voltage shift (ΔV_TH) through theoretical and experimental analyses. By examining the physical principles of threshold switching and conducting defect state analysis, the ΔV_TH as a memory window is confirmed to be attributed to the dynamics of charged defects and their gradient near electrodes, influenced by the nonuniform electric field after threshold switching. This study provides critical insights into the operational mechanism of OTS-based SSM, known as selector-only memory, highlighting its advantages for developing high-density, low-cost, and energy-efficient memory technologies in the artificial intelligence era.