Effects of Al content on the electrical properties of La_xAl _yO_z films grown on TiN substrate by atomic layer deposition

The effects of Al content on the electrical properties of Lax Aly Oz films grown on TiN substrate by atomic layer deposition technique were investigated. With increasing Al content, the leakage current characteristics improved, but the dielectric constant became smaller. Postannealing of the films at temperatures up to 500 °C reduced the leakage current density due to thermal stabilization by the addition of Al. For the 25-nm -thick La2.4 Al O3.3 film, the authors obtained a dielectric constant of 22 and a leakage current density of 10-7 A cm2 at 1 V after postannealing at 450 °C, which gives an equivalent oxide thickness of 3.8 nm.