Ru doping enhanced resistive switching behavior in InGaZnO thin films

In this paper, ruthenium (Ru) doped InGaZnO (IGZO:Ru) thin films were deposited by magnetron co-sputtering and the resistive switching behaviors were investigated. It was found that an appropriate Ru doping could weaken the bonding interaction between metal and oxygen atoms, facilitate the formation of robust conductive filaments, and enhance the electrical field locally, resulting in significantly enhanced bipolar resistive switching properties and a stable OFF/ON ratio of 10⁵. But an excessive doping of Ru would accelerate the nucleation and formation of conductive filaments and, tiny and fragile conductive filaments were unexpectedly generated. In such a case, a high resistive state was reached even when no negative bias voltage was applied, resulting in volatile resistive behavior. A model was suggested to understand the effect of Ru doping on the properties of the thin films.