TEXTURE CONTROL OF PBTIO3 AND PB(ZR,TI)O-3 THIN-FILMS WITH TIO2 SEEDING

The nature and the role of 1 to 5 nm thick TiO2 seed layers for the gr owth of textured PbTiO3 and Pb(Zr, Ti)O-3 thin films on textured Pt(11 1) thin film substrates have been studied. Under otherwise identical i n situ sputter deposition process conditions, the PbTiO3 texture could be turned from (100) to (111) orientation by adding the seed layer. T his is demonstrated by patterning the TiO2 film. Auger electron spectr oscopy and x-ray photoemission spectroscopy showed that the seed layer was a continuous TiO2 film. X-ray photoelectron diffraction measureme nts revealed epitaxial ordering in the seed layer. As there is no azim utal order among the Pt grains, the reduced information of azimutally averaged polar cuts is obtained. These give strong evidence for a stra ined rutile (110) structure. Various deposition experiments indicated that the TiO2 is effective only when it is ordered before the PbTiO3 n ucleation starts. The epitaxial relationship between PbTiO3(111) and P t(111) is thus mediated by the intermediate, epitaxial TiO2 film, whic h is dissolved of transformed to PbTiO3 afterwards. The observed growt h behavior is discussed in terms of surface and interface energies. (C ) 1998 American Institute of Physics. [S0021-8979(98)03607-X].