Bipolar resistive switching studies in amorphous barium titanate thin films in Ag/am-BTO/ITO capacitor structures

Abstract

The electroforming free bipolar resistive switching characteristics of amorphous barium titanate (am-BTO) thin films in Ag/am-BTO/ITO capacitor structures were systematically evaluated. The dot point capacitor structures were fabricated by using RF-DC sputtering deposition on ITO coated commercial glass substrates. Varied thicknesses of 142, 100, and 70 nm am-BTO thin films were utilized as a switching medium for exploring the resistive switching phenomena. The amorphous nature and topographical surface were probed with X-ray diffraction and atomic force microscopy techniques. The on/off resistance ratios, SET, RESET voltages, retention, and endurance parameters extracted from current-voltage (I-V) measurements demonstrate stable resistive switching. Space charge limited current conduction and ohmic conduction phenomena were found to be dominant in high resistance and low states of the junctions. The rupture formation upon the Ag active electrode and reduction in capacitance after the application of voltage specify the silver Ag+ ion mediated filament conduction mechanism for the observed bipolar switching phenomena.