Time-dependent electroforming in NiO resistive switching devices

Time-dependent electroforming phenomena in NiO capacitors are investigated. Different current-voltage characteristics between dc sweep mode and pulse mode indicate that electroforming is time-dependent process. Statistical time-dependent dielectric breakdown (TDDB) measurements show the exponential dependence of electroforming time on applied voltage, confirming that forming process is not a spontaneous process at some critical voltage, but an upsurge process resulting from stress-induced defects. The statistical TDDB analysis explains not only the nature of electroforming process but also the anomalous forming and large variations in forming parameters.