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

Abstract

In this study, we demonstrate forming-free and reliable resistive switching (RS) characteristics by controlling the stoichiometry of niobium nitride (NbNx) films. Compared to a perfect stoichiometric NbNx film, a decrease of 6% nitrogen content and an increase of 5% O-2 content are found in the sub-stoichiometric NbNx sample (s-NbNx), and a structural change for the s-NbNx film is observed from X-ray diffraction results, which results in the possibility of abundant defect generation in the s-NbNx film at virgin state. In the RS test, the s-NbNx film normally carries out well without initial forming because of the already-formed conducting filaments; in particular, in the reliability study, the s-NbNx film shows more stable dc cycling characteristics for 1000 cycles without any degradation and smaller variations in the operating current and voltage characteristics. (C) 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim