Multilevel unipolar resistance switching in TiO2 thin films

Abstract

We report on multilevel switching behavior in the unipolar resistance switching of TiO2 thin films. Multiple metastable states were observed during the reset process by measuring I-V curves. As observed using a conducting atomic force microscope, the multilevel resistance switching was accompanied by decreases in area and in the conductance of the top surface conducting regions. These experimental observations at both the macroscopic and microscopic levels could be explained by using the "random circuit breaker network" model, which is a dynamic bond percolation model. © 2009 American Institute of Physics.