ScholarWorks@동국대학교

초록

This study demonstrates solution-processed Ti/HZO/n+-Si write-once-read-many-times (WORM) memory devices. By systematically evaluating HZO resistive switching (RS) layers annealed from 300 degrees C to 900 degrees C, we establish a direct correlation between temperature-dependent evolution of oxygen vacancies, structural crystallinity, and the resulting RS performance. XPS and XRD analyses reveal that increasing the temperature facilitates a structural transition of the HZO films from an amorphous state to a polycrystalline monoclinic phase, while reducing the oxygen vacancy concentration from 43.9% to 17.3%. Temperature-dependent measurements combined with different voltage sweep directions confirm that the RS mechanism of the memories is governed by oxygen-vacancy conductive filaments. The 700 degrees C-annealed device exhibits optimal performance, featuring an ultralow OFF-state current of similar to 10-11 A, a remarkable ON/OFF current ratio of similar to 107, and high-speed switching of similar to 30 ns with a low programming energy of similar to 114.4 pJ, while maintaining robust data retention and read-disturb immunity extrapolated to safely exceed 10 years at an elevated temperature of 85 degrees C. This filamentary process is degraded at lower temperatures by excessive leakage paths and is completely suppressed at 900 degrees C due to severe vacancy reduction and the formation of a highly insulating monoclinic HfO2 phase.