On the properties of conducting filament in ReRAM

The conducting properties of resistive switching filaments in ReRAM are studied. Departing from first-principle simulations of electron transport along paths of oxygen vacancies in HfO₂, the Quantum Point Contact model is reformulated in terms of a bundle of such vacancy paths. By doing this, the number of model parameters is reduced and a much clearer link between the microscopic structure of the conductive filament and its electrical properties can be provided. As an example, a simple geometrical model for the microscopic structure of the CF is proposed and it is used to track the change of the conducting properties during the set/reset transitions. The model has been further checked by measurements at the nanoscale by means of CAFM.