Study of automatic recovery on the metal nanocrystal-based $Al2O3/SiO2$ gate stack

Automatic recovery of leakage current to its prestress condition was observed after soft breakdown on Ru metal nanocrystal-based $Al2O3/SiO2$ gate stack. We propose that the high current density induced upon breakdown causes considerable Joule heating in the breakdown percolation path. This increases the probability of detrapping and thermal diffusion of the oxygen ions which passivates the oxygen vacancies in the percolation path. This recovery mechanism is supported by studies on leakage current and dielectric relaxation current at elevated temperatures. We discuss the significance of our findings in the lights of enhancing the reliability margin of metal nanocrystal-based nonvolatile memory.