Effects of the electroforming polarity on bipolar resistive switching characteristics of SrTiO3-δ films

ArticleinApplied Physics Letters 97(11):112101 - 112101-3 · October 2010with45 Reads
DOI: 10.1063/1.3488810 · Source: IEEE Xplore
Abstract
The effects of the electroforming polarity on the bipolar resistive switching characteristics in SrTiO <sub>3-δ</sub> thin films have been investigated. The conduction mechanisms of high resistance state and low resistance state are Poole–Frenkel emission and tunneling, respectively. The temperature dependences of the resistance at high and low resistance state are both semiconductorlike. The impact of the polarity of the electroforming voltage on the resistive switching mechanism and the distribution of defects was discussed. A simple model describing the combination of bulk and the interface effect was proposed to explain the resistive switching in this material.
    • "The HRS resistance de-creases with the increasing temperature; the accumulated large number of oxygen vacancies modulates the conductivity of the oxide, which exhibits a typical semiconductor behavior [18]. By contrast, the LRS resistance evidently decreases with the decreasing temperature, which exhibits the feature of a metal conduction mechanism [19]. The resistance of the LRS in the Al/STN/ITO structure is inversely proportional to the temperature, whereas the resistance value increases with increasing temperature in the Pt/STN/ITO/glass memory device. "
    [Show abstract] [Hide abstract] ABSTRACT: Strontium titanate nickelate (STN) thin films on indium tin oxide (ITO)/glass substrate were synthesized using the sol-gel method for resistive random access memory (RRAM) applications. Aluminum (Al), titanium (Ti), tungsten (W), gold (Au) and platinum (Pt) were used as top electrodes in the STN-based RRAM to probe the switching behavior. The bipolar resistive switching behavior of the set and reset voltages is in opposite bias in the Al/STN/ITO and Pt/STN/ITO RRAMs, which can be partly ascribed to the different work functions of top electrodes in the ITO. Analyses of the fitting results and temperature-dependent performances showed that the Al/STN/ITO switching was mainly attributed to the absorption/release of oxygen-based functional groups, whereas the Pt/STN/ITO switching can be associated with the diffusion of metal electrode ions. The Al/STN/ITO RRAM demonstrated a high resistance ratio of >106 between the high-resistance state (HRS) and the low-resistance state (LRS), as well as a retention ability of >105 s. Furthermore, the Pt/STN/ITO RRAM displayed a HRS/LRS resistance ratio of >103 and a retention ability of >105 s.
    Full-text · Article · Oct 2015
    • "In the context of oxide-based electronic devices, strontium titanate-SrTiO 3 (STO) is often considered the prototypical oxide material. Signifi cant attention has been paid to niobium-doped STO (SrTi 1−x Nb x O 3 or NSTO) as an n-type semiconductor789101112131415 and to the related M/NSTO Schottky junctions, exhibiting reversible resistance switching (RS) between different states in their current-voltage (I–V) curves.16171819202122232425 This property is known as Colossal Electro Resistance (CER). "
    [Show abstract] [Hide abstract] ABSTRACT: Novel ballistic electron emission microscopy experiments are reported, aimed to directly visualize and quantify the local inhomogeneities of the effective Schottky barrier height on Au/Nb:SrTiO3 Schottky junctions dominated by interfacial resistance switching effects. The voltage-dependent variation of the local barrier height of the nanometric patches could explain the non-ideal behaviour of the resistance switching effects in transition-metal oxide cells.
    Article · Jun 2014
  • [Show abstract] [Hide abstract] ABSTRACT: Ag/0.7 wt% Nb-doped SrTiO3 (Nb:STO)/Ti structure was prepared by sputtering Ag and Ti electrodes on a Nb:STO single crystal substrate and the resistance switching (RS) properties were investigated. Reversible multilevel resistance switching behavior was obtained by applying different voltages. The resistance switching (RS) effect comes from the Schottky barrier existed between Ag and Nb:STO interface. The multilevel switching mechanism may be related to the different number of electrons trapped or detrapped by oxygen vacancies (Vo2+) at the Ag/Nb:STO interface, which can change the width of depletion layer. The temperature dependence on resistance of Ag/Nb:STO/Ti suggests that both high resistance state (HRS) and low resistance state (LRS) are of semiconductor behavior. Substrate annealing in vacuum degrades the RS properties of Ag/Nb:STO/Ti structure due to the increase of Vo2+ in Nb:STO.
    Full-text · Article · Oct 2012
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