Resistive Switching in $\hbox{CeO}_{x}$ Films for Nonvolatile Memory Application

$\hbox{Al}/\hbox{CeO}_{x}/\hbox{Pt}$ devices with nonstoichiometric $\hbox{CeO}_{x}\ (\hbox{1.5} ≪ x ≪ \hbox{2})$ films were fabricated. The unique resistive switching (RS) behaviors for resistive random access memory applications, including stable and sharp bipolar RS processes and a multilevel and self-stop set process without current compliance and without excessive requirement on a high-voltage electroforming process, were demonstrated. A multifilament switching model based on the distribution characteristics of oxygen vacancies in $\hbox{CeO}_{x}$ films is proposed to explain the observed RS behaviors.