Forming‐free resistive switching characteristics and improved reliability in sub‐stoichiometric NbNx films

In this study, we demonstrate forming‐free and reliable resistive switching (RS) characteristics by controlling the stoichiometry of niobium nitride (NbN_x) films. Compared to a perfect stoichiometric NbN_x film, a decrease of 6% nitrogen content and an increase of 5% O₂ content are found in the sub‐stoichiometric NbN_x sample (s‐NbN_x), and a structural change for the s‐NbN_x film is observed from X‐ray diffraction results, which results in the possibility of abundant defect generation in the s‐NbN_x film at virgin state. In the RS test, the s‐NbN_x film normally carries out well without initial forming because of the already‐formed conducting filaments; in particular, in the reliability study, the s‐NbN_x film shows more stable dc cycling characteristics for 1000 cycles without any degradation and smaller variations in the operating current and voltage characteristics. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)