Structural and electrical properties of TixAl1−xOy thin films grown by atomic layer deposition

Abstract

Ternary oxide TixAl1−xOy thin films with a wide Ti/Al ratio have been grown by atomic layer deposition technique. As grown titanium aluminate films are shown to be a homogeneous alloy and exhibit the amorphous structure in the whole compositional range, while rapid thermal processing (RTP) induces the crystallization of binary and ternary phases once the composition of TixAl1−xOy film is close to the specific phase stoichiometry. The permittivity κ varies in the range κ=12–30 depending on Ti/Al ratio in the film. A 0.5-nm-thick SiO2 layer formed at the film/Si interface during the deposition grows up to 2 nm upon RTP and presumably affects the leakage current, decreasing three orders of magnitude upon annealing.