Real time x-ray observation of lattice pulling during growth of epitaxial Pb(Zr,Ti)O3 films

Using surface-sensitive grazing incidence synchrotron x-ray scattering and fluorescence, the authors have monitored the evolution of strain and Zr composition in situ during metal-organic chemical vapor deposition of Pb(Zr,Ti)O3 epitaxially grown on (001) SrTiO3. The Zr fraction of the growing surface increases dramatically as the film relaxes, resulting in compositional nonuniformity in the growth direction. The observed composition variation can be quantitatively explained by the lattice pulling model, which includes strain energy in the thermodynamic equilibria for growth.