Optimization of PZT Thin Film Crystalline Orientation Through Optimization of TiO2/Pt Templates

摘要

Titanium dioxide (TiO2) seed/adhesion layers were produced by sputter depositing 15-45-nm thick Ti films on thermally grown silicon oxide (SiO2) using a range of deposition conditions including deposition time, cathode power, and argon (Ar) gas pressure gas flow. The Ti films were oxidized and converted to the rutile TiO2 phase by annealing in a tube furnace and were characterized by X-ray diffraction and ellipsometry. A 100-nm platinum (Pt) electrode layer was then sputter-deposited at 500 deg C onto the TiO2 seed layer. The Pt (111) orientation templates from the underlying (100) textured TiO2 film, which forms during oxidation of the (0002) textured Ti film. Analysis of the 222 Pt X-ray diffraction peak shows an 8-fold improvement in peak height and a decrease in rocking curve full-width-at-half-maximum (FWHM) from 9 deg to 2 deg for the Pt deposited on an approximately 30 nm TiO2 template compared to the same Pt process used for deposition onto a Ti template. Use of the Pt/TiO2 electrode for growth of PZT(52/48) results in films with 90% textured volume fraction, which is expected to improve electrical properties of the PZT films.