Preparation of BiFeO3 multiferroic films by RF magnetron sputtering and structural and electrical characterizations

• Main Authors: Wen-chih Chang, 張文智
• Other Authors: Xiaoding Qi
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/01746198014720280624

碩士 === 國立成功大學 === 材料科學及工程學系碩博士班 === 96 === In this study, BiFeO3 films have been deposited by RF magnetron sputtering. The films were first sputtered at room temperature and then the BiFeO3 phase was formed after post-growth sintering at high temperature. A range of targets of varying compositions were used for the deposition of the suitable “precursor” films. The phase purity and microstructures of the sintered films were studied for different sintering temperatures and times, as well as different oxygen partial pressures. The leakage currents for the films prepared under different conditions were also examined. We found that (1) BiFeO3 phase were easier to form in the films sputtered from the targets containing small excess of Bi, (2) the BFO structure only grew under certain oxygen partial pressures, (3) high-purity expitaxial BiFeO3 films could be grow on (001) SrTiO3 single crystal substrates under the optimum condition. The ferroelectric measurements showed that the films had large leakage currents and as a consequence, the polarization-electric field (P-E) hysteresis loops were unable to reach a saturated state. The leakage current had a tendency to increase as the annealing temperature.