Nitrogen‐Doped GeTeS Ovonic Threshold Switching Selector With Optimized Performance Trade‐Off for 1S–1R Phase‐Change Memory

Ovonic threshold switching (OTS) selector devices are critical for suppressing sneak‐path leakage current and ensuring cell selectivity in high‐density crosspoint memory arrays, while enabling nanosecond‐scale switching and low‐power operation. However, amorphous chalcogenide‐based OTS selectors face challenges including limited durability, poor thermal stability, and an inherent trade‐off between switching speed and threshold voltage ( V th ). To address these issues, this study proposes a Ge–Te–S (GeTeS) mixed composition fabricated by co‐sputtering Te and S, combining the fast switching and low V th of GeTe with the high durability and thermal stability of GeS. Nitrogen‐doped GeTeS (N‐GeTeS) was then developed by incorporating nitrogen into the GeTeS matrix. Nitrogen doping suppresses unstable bonds via strong S─N bond formation, reduces trap density, improves V th uniformity, and widens the band gap to reduce off‐current. The resulting N‐GeTeS OTS device demonstrates excellent durability (≈10 10 cycles), high crystallization temperature (≈470°C), fast switching speed (≈18 ns), low V th (≈1.5 V), low leakage current (≈2.8 × 10 −9 A), and a high on/off ratio (≈3×10 5 ). In a one‐selector‐ one‐resistor configuration integrated with phase‐change memory, the N‐GeTeS selector enables stable memory cell operation through threshold voltage‐controlled current blocking. Overall, N‐GeTeS shows strong potential for scalable, high‐density memory array applications.