Structural and electrical properties of SrTiO3 thin films prepared by plasma enhanced metalorganic chemical vapor deposition

The structural and electrical properties of SrTiO3 thin films (30–75 nm in thickness) prepared by plasma enhanced metalorganic chemical vapor deposition on Pt/Si and Ir/Si substrates were studied in terms of their crystallinity, microstructure, current density, and dielectric constant. Deposition at higher rf powers (>180 W) resulted in a poor crystalline structure mainly due to the sputtering effect. The surface morphology showed a quite smooth surface, but was independent of the substrate. The current density decreased as the deposition temperature increased up to 550 °C, and increased somewhat at 580 °C. The I-V characteristics showed that the conduction mechanism of the SrTiO3 film capacitor was controlled by the Schottky emission for thick films (>30 nm), but by the tunneling effect for the films thinner than 30 nm. The potential barrier height and the electron affinity of the SrTiO3 films were 1.2 and 4.0–4.3 eV, respectively.