The lead-free ferroelectric bismuth ferrite (BiFeO3: BFO) has attracted a great deal of attention because of its superior thin-film ferroelectric properties. In this paper the relationship between the ferroelectric properties of BFO thin films and the their crystal orientations, and the effect of the substrate kinds, i.e. Si and yttria stabilized zirconia (YSZ) were investigated. We have controlled the crystal orientations of the SrRuO3 (SRO) and BFO thin films. The (111) and (110) epitaxial SRO thin films were deposited on the YSZ/Si(001) substrate by introducing the atomic layer buffer, 1.0nm and 0.25nm of TiO2, respectively. The (001) epitaxial SRO thin film was deposited on CeO2/YSZ/Si(001) substrate by insertion of 0.43nm of MgO. We apply the same buffer layers between SRO thin film and YSZ substrate. The same tendency was observed as the SRO thin film deposited on Si substrate. We selected the Mn doped BFO (BiFe0.97Mn0.03O31): BFMO) to reduce the leakage current of non-doped BFO. We successfully fabricated the BFMO thin films with (111), (110) and (010) crystal orientations on both Si and YSZ substrates with appropriate buffers. The remanent polarization (Pr) of the (111) orientation is 76 ｼC/cm2 measured at 100 kHz at RT. The other orientations, (110) and (010) show lower Pr values, 64 and 43.5 ｼC/cm2, respectively. The order of the Pr values of BFMO is (111)>(110)>(010) which agrees with predicted order from crystallographic considerations based on the spontaneous polarization (Ps) axis, <111>. The reported Pr value of epitaxial (010) BFMO thin film1) on SRO/STO substrate is larger than that of our Pr value of (010) BFMO on Si substrate. This tendency corresponds to the degree of the tensile stress of BFMO by the buffered substrate.
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