Quaternary alloyed HfAlTiO thin (similar to 4-5 nm) films in the wide range of Ti content have been grown on Si substrates by Atomic Layer Deposition technique, and the effect of both the film composition and the interfacial reactions on the electrical properties of HfAlTiO films is investigated. It is shown that depending on the Ti content, the permittivity and the leakage current density I-leak, in HfAlTiO films vary in the range k = 18 divided by 28 and 0.01-2.4 A cm(-2), respectively. The incorporation of ultra thin SiN interlayer in Al/HfAlTiO/SiN/Si stack gives rise to the sharp (x10(3)) decrease of the I-leak similar to 6.10(-5) A/cm(2) at the expense of the rather low capacitance equivalent thickness similar to 0.9 nm. (C) 2011 Elsevier B.V. All rights reserved.