Investigation of Resistance Switching Properties in Undoped and Indium Doped SrTiO 3 Thin Films Prepared by Pulsed Laser
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1160-H11-01
Investigation of resistance switching properties in undoped and Indium doped SrTiO3 thin films prepared by pulsed laser deposition Weidong Yu, Xiaomin Li, Yiwen Zhang, and Lidong Chen State Key Laboratory of High Performance Ceramics & Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Ding Xi Road, Shanghai 200050, People’s Republic of China ABSTRACT In this paper, the undoped SrTiO3 (STO) and Indium doped STO (SrTi1-xInxO3: STIO) thin films were grown on Pt/Ti/SiO2/Si substrates by pulsed laser deposition with low substrate temperature. For undoped STO film, the influences of the forming processes on their resistive switching properties were studied by current and voltage controlled I-V sweeps, respectively. An obvious current controlled negative differential conductance phenomenon was found in both polarities of the electrical field. However, for low Indium doped STIO (x=0.1), the filament related resistance switching was observed in both the current and voltage I-V sweeps. And for high Indium doped STIO (x=0.2), a resistance switching with a reverse direction change to that in undoped STO can be obtained by a proper forming process. Based on these results, the reversible change of the Schottky like barrier at the grain boundary by the migration of oxygen vacancies were proposed to interpret the mechanism of the resistance switching. INTRODUCTION Some transition metal oxides including SrTiO3, PCMO, NiO, CoO, and TiO2 have attracted considerable attention as their stable reversible resistance change properties under a proper electrical exertion, which can be defined as “0” and “1” states for the potential application in a novel nonvolatile memories, named resistance random access memories (RRAM).[1-5] Among them, SrTiO3 (STO) based materials , in particular SrTiO3 based single crystal, which are well suited to serve the investigation of resistance reversible changes as it has a simple cubic structure in the room temperature, a model band insulator and can be modified easily by doping trivalent (Cr3+) and pentavalent (Nb5+) metal atoms. The filamentary mechanism related to the extended defects, such as dislocations, has been elucidated to explain the resistance switching of STO single crystals.[6] The electromigration of oxygen in the upper segment of the defect network drives the switching process. In addition, some reports exhibited the stable resistance switching properties in the heterojunctions of metal/STO [7] and STO/NbSTO [8], which can also be explained by the roles of the interfaces of the junctions. However, due to the high preparation temperature (800℃) and strict substrate demand, the single crystal STO films can not be used for the Si integration devices at the present stage. The oxides used in IC technology such as SiO2 and high K gate material HfO2, ZrO2 etc, are usually fabricated at low temperature (
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