Improved uniformity and threshold voltage in NbOx-ZrO2 selectors

Selectors with an excellent performance exhibit great potential to achieve a high integration density and contribute to the design of peripheral systems. However, the uniformity and stability need to be optimized. We demonstrate a high-performance ZrO2/NbOx threshold switching selector that exhibits a low-threshold voltage, ultra-high uniformity, and excellent voltage stability. The oxygen storage properties of the tunneling layer cause a thinner NbO2 region and optimize the performance, which is confirmed by thermal simulations and compositional analyses. The conduction mechanism of the OFF state is fit and verified to be Schottky emission. Compared with the reference device, the tunneling device has a smaller Schottky distance, which indicates a thinner NbO2 region. This work provides an effective method to improve the performance of the selector and understand its physical mechanism.