PREPARATION OF Al-DOPED PbTiO3 THIN FILMS BY METALORGANIC CHEMICAL VAPOR DEPOSITION AND THEIR CHARACTERIZATION

Al-doped PbTiO3, Pb(Al, Ti)O3, thin films were prepared by MOCVD from the Pb(C11H19O2)2-Al(O.n-C3H7)3-Ti(O.i-C3H7)4-O2 system. Al content of the film could be controlled only by changing the input gas concentration of Al(O.n-C3H7)3, and was independent of the deposition temperature from 400 to 620 C. Lattice parameter change of the film showed that the solubility limit of Al atoms into perovskite phase existed in the vicinity of 8 at.%. Leakage current density of the film deposited on (111)Pt/Ti/SiO2/(100)Si substrate decreased with increasing Al content up to 33 at.%. The thin film with 4.1 at.% Al content showed ferroelectricity, and the twice the values of remanent polarization (2Pr) and the coercive field (2Ec) were 8.5 mu C/cm2 and 90 kV/cm, resp. The epitaxial Pb(Al, Ti)O3 thin film was deposited on (110)SrRuO3//(110)SrTiO3 substrate, and the 2Pr and the 2Ec values were 27.5 mu C/cm2 and 200 kV/cm, resp. 14 refs.