Investigation on the effects of PbO content and seeding layers of TiO2 and ZrO2 on the orientation and microstructure of Pb(Zr0.52Ti0.48)O3 ferroelectric films grown by reverse dip-coating method of sol–gel

Abstract

Lead zirconate titanate Pb(Zr0.52Ti0.48)O3 (PZT) thin films were grown on Si (100) and Pt(111)/Ti/SiO2/Si(100) substrates by a new reverse dip-coating method of sol–gel process. The method was first proposed and applied to coat films. It has several advantages over the conventional sol–gel coating method, including: no consideration of the mechanical transmission that is difficult to manipulate with costly exact apparatus in classical dip-coating procession, convenient processing control, simplicity, low cost, less pollution, and easy fabrication films on large areas and irregular shaped devices etc. This paper studied the factors including PbO content of precursor, TiO2 and ZrO2 layers, which are related to raw materials of PZT precursor and influence greatly the crystal orientation of the final thin films. We find that the PZT films deposited by precursor with 20% mole excess Pb displayed strong (111) preferred orientation, with 5% mole excess Pb showed a little (100) orientation and pyrochlore phase. The precursor with 10% mole excess Pb was found prompting the PZT films phase transformation with (110) preferred orientation. In addition, the results show that the TiO2 and ZrO2 seeding layers had totally different effects on the preferred orientation of PZT films. The films with TiO2 seeding layer were highly (111) oriented and exhibited better ferroelectric properties (remnant polarization Pr=14.2 μC cm−2, coercive field Ec=59.1 Kv cm−1) than those of the films with ZrO2 seeding layer shown (100) orientation (Pr=7.4 μC cm−2, Ec=42.9 Kv cm−1).