High‐Throughput Characterization of Metal Electrode Performance for Electric‐Field‐Induced Resistance Switching in Metal/Pr_0.7Ca_0.3MnO₃/Metal Structures

Abstract

Electric-field-induced switching of resistance [1][2][3][4][5][6][7] has attracted great interest for potential applications in high-performance nonvolatile memory devices known as resistance random access memory (RRAM). [8] Compared to other nonvolatile memory, RRAM has several advantages, such as fast writing times, high densities, and low operating voltages. Switching behavior, as characterized by current-voltage (I-V) data, has been reported in various materials, including metal oxides [1][2][3][4][5][6] and organics. [7] Switching has been observed in both single crystals and polycrystalline materials. According to published studies, switching only occurs in single crystals and epitaxial films when two different types of electrodes are used. On the other hand, switching has been seen in polycrystalline materials, even when the same type of electrode material was used for both electrodes. [2] To date, several models have been proposed to explain this phenomenon: field-induced defects that affect the interface state density, [3] electrons trapped in interface states that change Schottky-like barrier heights, [4] electron injections that change the local atomic structure, [5] and dielectric breakdown that generates filamentary metallic paths. [6,9] However, the essential factors for resistance switching have not yet been identified. Here, we performed high-throughput exploration of electrode materials for an epitaxial thin-film device to determine the appropriate structure and electrode materials required for achieving resistance-switching memory. This work was also helpful for understanding the mechanism of electric-field-induced resistance switching. Fabrication of several types of metal electrodes on an epitaxial Pr 0.7 Ca 0.3 MnO 3 (PCMO) layer and I-V characterization of electrode pairs were carried out by using combinatorial methodology. [10] This methodology ensured a rapid screening of the resistance-switching effect from among many combinations of different materials. Epitaxial PCMO thin films were grown on LaAlO 3 (100) (LAO) single-crystal substrates by pulsed laser deposition (PLD). Coherent growth of the epitaxial PCMO thin film was confirmed by four-circle X-ray diffraction (4cXRD) measurements. Detailed analysis of the 4cXRD pattern revealed that the PCMO thin film was compressively strained on the LAO substrate. Atomic force microscopy (AFM) images showed that the surface of the epitaxial PCMO thin film was atomically flat. Mg, Ag, Al, Ti, Au, Ni, and Pt electrodes with a diameter of 0.2 mm were fabricated on a 10 mm × 10 mm PCMO epitaxial thin film, as shown in Figure 1b. Two-probe I-V characteristics, pulsed-field resistance, and four-probe I-V characteristics were measured for various metal-electrode combinations. Figure 1a shows the I-V characteristics for various combinations of metal electrodes. The applied voltage was swept at a rate of 0.1 V s -1 . The electrode materials are sorted by their work functions.[11] Switching phenomena were clearly observed in pairs of electrodes comprising ...

Impact of Defect Distribution on Resistive Switching Characteristics of Sr2TiO4 Thin Films

“…Thanks to recent further intensive investigations, there exists some general agreements in oxides that the migration of oxygen vacancies (or oxygen ions) under an applied electric field plays an important role [5,7,[13][14][15] and that interface effects are more pronounced than bulk switching. [10][11][12]15] Two basic models have been proposed: (i) local redox process based on oxygenvacancy migration (or oxygen diffusion) [9] including an electrochemical interface reaction [5] and (ii) change in Schottky-like barrier height and/or width by trapping/detrapping effects at interface defect states. [11] Although no attention has been paid to it in the literature yet, these two mechanisms exhibit different switching polarities.…”

Non-Volatile Resistive Switching in Graphene Oxide Thin Films

“…As can be seen, V Set and V Reset distribute in a range of 0.3 V to 1 V and -0.3 V to -0.9 V, respectively. The switching threshold voltages of the Cu/GO/Pt sandwiched structure are lower than those of most reported RRAM devices (Szot et al, 2006;Tsubouchi et al, 2007;Guan et al, 2007;Fujiwara et al, 2008;Li et al, 2008). The retention performance of the Cu/GO/Pt memory cell at room temperature is shown in Fig.…”

Device size dependence of resistance switching performance in metal/manganite/metal trilayers

“…There are questions as to whether resistance switching happens inside the insulator layers [2,3] or at the interfaces between metal electrodes and insulator layers [4][5][6][7][8][9]. In the case of epitaxial Pr 1−x Ca x MnO 3 , the resistance switching occurs at the interfaces between Pr 1−x Ca x MnO 3 and metal electrodes which can form Schottky-like barrier with Pr 1−x Ca x MnO 3 [6,10]. Our previous research also has revealed that the resistance switching occurs at the Al/Pr 1−x Ca x MnO 3 interfaces [10].…”

“…In the case of epitaxial Pr 1−x Ca x MnO 3 , the resistance switching occurs at the interfaces between Pr 1−x Ca x MnO 3 and metal electrodes which can form Schottky-like barrier with Pr 1−x Ca x MnO 3 [6,10]. Our previous research also has revealed that the resistance switching occurs at the Al/Pr 1−x Ca x MnO 3 interfaces [10]. For more deeply understanding the resistance switching at the Al/Pr 1−x Ca x MnO 3 interfaces, investigations of device size dependences of resistance switching performances are needed.…”