Weibull analysis of the kinetics of resistive switches based on tantalum oxide thin films

Abstract

We study the kinetics of bipolar resistive switches in tantalum oxide thin films having different thicknesses. The time to switch from the high resistance state to the low resistance state (SET) is measured repeatedly in a single cell of each sample and analyzed based on a Weibull distribution. In the thin film device the Weibull parameter fJ> 1 is observed in the short time region, followed by a distribution with ß <; 1 in the long time region. This indicates that a progressing phenomenon induces the SET action in the short time region, while it is saturated in the long time region, where the SET is triggered by a sporadic event. In the thick film sample a distribution with ß<; 1 is dominant almost in the whole time range. Further analysis revealed that the heat generated before the switch-on can be responsible for the SET in the fJ> 1 mode.