Dielectric oxynitride LaTiOxNy thin films deposited by reactive radio-frequency sputtering

LaTiOxNy thin films have been deposited by RF sputtering on (001) Nb-doped SrTiO3 and (001) MgO single-crystalline substrates at high temperature (TS = 800 °C) under different nitrogen ratios in the plasma (vol.% N2 = 0, 25, 71). The band gaps ranged from Eg = 3.30 eV for the epitaxial transparent film containing no nitrogen to Eg = 2.65 eV for the textured coloured film containing a moderate amount of nitrogen. Dielectric characterization in the frequency range [100 Hz–1 MHz], using a metal-insulator-metal structure, has shown a stable permittivity and loss tangent of the epitaxial low-nitrided LaTiOxNy film with values of ε′ = 135 and tanδ = 1.2 10− 2 at 100 kHz (RT).