| AVS 54th International Symposium | |
| Thin Film | Thursday Sessions |
| Session TF-ThP |
| Session: | Aspects of Thin Films Poster Session |
| Presenter: | K. Wasa, Kyoto University, Japan |
| Authors: | K. Wasa, Kyoto University, Japan I. Kanno, Kyoto University, Japan H. Kotera, Kyoto University, Japan T. Zhang, Nanjing University, China F. Li, Nanjing University, China S.-Y. Zhang, Nanjing University, China |
| Correspondent: | Click to Email |
It is well known bulk ferroelectric oxide ceramics of modified Pb(Zr,Ti)O3 (PZT) , PbMn1/3Nb2/3O3- PZT, show variety of ferroelectric properties when we change the doping level of Mn and Nb. Thin films of the modified PZT will be useful for a fabrication of micro- and/or nano- level functional device including GHz electronic devices, since the co-doping of Mn and Nb to pure PZT will improve both mechanical Q values and electromechanical coupling of original PZT. However, it is not clear whether the bulk ferroelectric properties will be achieved in the ferroelectric thin films. We have tried to make epitaxial growth of thin films of the modified PZT, xPbMn1/3Nb2/3O3- (1-x)PZT ,on (001)MgO substrates by rf-magnetron sputtering at x=0.06 and PZT(45/55). Before the epitaxial growth of the modified PZT, (001)Pt electrode with SrRuO3 buffer layer was epitaxially grown on the MgO substrates by the rf-magnetron sputtering. The epitaxial temperature of the modified PZT thin films was around 600oC and the epitaxial films showed (001) single orientation of tetragonal structure. The dielectric constant of the co-doped epitaxial thin films at 1.7 µmm in film thickness was ε*=190 at 100kHz and showed sharp square shape P-E hysteresis curve with Pr=60µmC/cm2 and Ec=110kV/cm. The bulk dielectric constant of modified PZT is ε*=300 to 400. The structural differences between bulk and thin films will cause the sharp square type P-E curve with smaller dielectric constant for thin films. The epitaxial thin films showed high piezoelectric constant, e31 =4C/m2 , which was almost the same to the highest value of piezoelectric constant observed in the pure PZT(52/48) thin films at MPB condition. The present Mn and Nb doped PZT thin films show tetragonal structure which achieves the fine interface between thin films and the substrates. Since the doping of Mn will increase the mechanical Q values, the modified PZT thin films with lower dielectric constant will be applicable for the fabrication of the nano-level functional devices including GHz film bulk acoustic resonator (FBAR).