Composition-sensitive growth kinetics and dispersive optical properties of thin Hf x Ti 1−x O 2 (0 ≤ x ≤ 1) films prepared by the ALD method

The optical quality HfxTi1−xO2 films with a wide range of the Hf/Ti ratio were prepared on Si (100) substrates by the ALD method with the use of tetrakis(ethylmethylamido)hafnium(IV) (Hf(NC2H5CH3)4, TEMAH) and titanium(IV) chloride TiCl4 as Hf and Ti precursors, respectively. The H2O vapor was applied as oxygen source. The structural properties of the as-deposited and annealed films were evaluated by the XRD analysis. The Hf/Ti ratio in the films was measured by energy dispersive spectroscopy and X-ray photoelectron spectroscopy. The dispersive optical constants were obtained by spectroscopic ellipsometry over the photon energy range of E = 1.12–4.96 eV. The specific growth kinetics is observed for 0 < x < 1. The optical constants wide-range tuning is reached in the HfxTi1−xO2 (x = 0–1) films via the chemical composition variation and annealing.