Preparation and properties of PbTiO₃-PbZrO₃ thin films by pulsed MO-source CVD method

Epitaxially-grown PZT thin-films with a compositional-gradient buffer layer Pb(Zr_xTi_1-x)O₃ (x=0∼0.5) were prepared on 0.5wt%Nb-doped SrTiO₃(100) and Si(100) substrates by the pulsed MO-source CVD method. The Zr/Ti composition ratios of the deposited PZT thin films were successively controlled by the valve opening time ratios of Zr and Ti sources. The gradient of composition in the buffer layer was confirmed by XPS depth profile analysis. The X-ray diffraction of the film with the structure [Pb(Zr_0.5Ti_0.5)O₃(50nm)]/[Pb(Zr _xTi_1-x)O₃(50nm)]/[PbTiO ₃(5nm)]/[Nb-SrTiO₃] revealed that the compositional-gradient buffer layer acted as a stress relaxation layer compared with Pb(Zr_0.5Ti_0.5)O₃ (50nm) film directly deposited on a Nb-SrTiO₃ substrate.