Structural and dielectric properties of oxynitride perovskite LaTiOxNy thin films

Oxynitride LaTiOxNy films have been deposited by sputtering with substrate temperature =[800-900 degrees C] and nitrogen ratio in the plasma =[0-71%]. Distinct nitrogen amounts in films were measured, in agreement with the observed variation of the bang-gap, from E-g=3.45 eV for the transparent film to E-g=2.20 eV for the coloured nitrogen-rich film. The films are polycrystalline, (001) oriented or epitaxially grown on Nb-doped SrTiO3 substrates. The dielectric constant epsilon' decreases with increasing nitrogen amount and polycrystalline character of films. The epsilon' values are high, ranging from 290 to 1220 (room temperature, 10 kHz). (c) 2008 Elsevier B.V. All rights reserved.