Modeling Electrical Switching Behavior of Carbon Resistive Memory

The amorphous carbon-based resistive memory has recently attained vast attention due to its non-volatility, fast switching speed, long data retention, and multilevel recording. However, the memory switching mechanism of amorphous carbon media remains mysterious and thus severely restricted its application prospect. To resolve this issue, a comprehensive three-dimensional model by simultaneously solving the current continuity equation, heat transfer equation, and mass concentration equation, is developed to model the physical conversions between sp2 and sp3 clusters. According to simulations, electric field was considered as the sole critical factor that determines the formation of conductive sp2 filament during the ‘SET’ process, whereas the ‘RESET’ process is mainly attributed to the induced high temperature that accelerates the growth of sp3 cluster and causes the rupture of the sp2 filament. It was additionally found that the sp2 filament was preferably formed inside the region having larger sp2 concentrations, and its rupture usually initiates from the filament center. The threshold voltages of carbon resistive memory for different thickness and different sp2 fractions were also calculated and exhibited good agreement with experimental measurements.