| Summary: | 碩士 === 國立成功大學 === 材料科學及工程學系碩博士班 === 91 === Effects of O2/Ar ratio, buffered Bi2O3 layers, and ion implantation on the ferroelectricity and microstructures of (Bi,La)4Ti3O12(BLT) and V-doped BLT(BLTVx) films deposited by radio-frequency sputtering were studied. The remanent polarization(2Pr) of BLTV0.03 films increased with the O2/Ar ration up to 1:1.5 and 1:1 and then decreased with the ratio layer than 1.5:1 due to the reduction of grain size. The BLTVx films with the V concentration in the range of x=0.03-0.07 owned the 2Pr large than that of BLT films, whereas the 2Pr of BLTV0.15 films dropped rapidly because reduction of lattice distortion V doping induced two contrary effect on 2Pr, i. e., reducing the amount of oxygen vacancies and causing less structure distortion. The buffered Bi2O3 layers enhanced the c-axis-oriented growth of BLT and BLTVx films, reducing the temperature for c-axis-oriented growth from 900 to 600℃. The cause can be attributed to the template effect of Bi2O3 and the lower interfacial energy of (001)BLT/Pt . The 2Pr of P+- and BF2+- implanted BLT and BLTVx films decreased with the ion dose in the range of 1-5x1015/cm2. The reduction of grain size induced by the ion implantation can enhance the domain pinning effect and thus reduce the remanent polarization.
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