Resistive Switching Models by Ion Migration in Metal Oxides

Resistive switching in metal oxides is considered one of the most promising storage concept for future generations of nanoscaled nonvolatile memories. In bipolar resistive switching, the resistance of a conductive filament (CF) is controlled through the application of electrical stimuli, and the conductive state of the nanoscaled CF can be used to encode the value of the logical bit in a nonvolatile memory. To investigate the scaling opportunities of the resistive switching concept, physical models must be developed. This chapter summarizes the current state understanding of bipolar resistive switching, providing evidence for the voltage across the device being the controlling parameter for the CF growth during set. A physical model for set and reset transition is then described, allowing for an interpretation of the observed switching characteristics for different timescales. Finally, the open challenges for the scaling and the reliability of resistive switching memories are briefly summarized.