Structural chemical and electric properties of Ti03Al0.7OY thin films grown by atomic layer deposition

Ternary oxide Ti0.3Al0.7Oу thin films with thickness 3-40 nm are grown by an atomic layer deposition technique. The grown titanium aluminate films are shown to be a homogeneous alloy and exhibit the amorphous structure in the whole thickness range, while rapid thermal processing (RTP) induces the crystallization of TiAl2O5 phase in the thickness range 20-40 nm. Thinner films remain amorphous after RTP. The permittivity k of annealed films varies in the range k = 14-19 depending on film thickness. The 0.5-nm-thick SiOх layer formeds at the Si-film interface, while the deposition grows up to 2 nm upon RTP and presumably affects the leakage current decreasing three orders of magnitude upon annealing. The optimal temperature of RTP for the maximization k and minimization leakage current densities is T = 700 °C.