Mechanism of localized electrical conduction at the onset of electroforming in TiO2 based resistive switching devices

The onset of localized current conduction during electroforming of TiO2-based resistive switching devices is investigated using a pulsed voltage method. The temperature rise at electroforming onset is found to vary from 25 to 300 degrees C as the pulse amplitude and the width are varied between 3-8 V and 10 ns-100 ms, respectively. The effective activation energy of the forming event is strongly electric field dependent and decreases from 0.7 eV at 3 V to almost zero at 8 V. The functional form of this dependence points toward charge trapping as the mechanism rather than oxygen vacancy motion. (C) 2014 AIP Publishing LLC.