In this work, a detailed study on the growth and composition of atomic layer deposited (ALD) titanium oxide (TiOx) films on crystalline silicon (c-Si) substrates is presented. The effects of deposition temperature from 100 to 400 degrees C and post-deposition annealing on the properties of TiOx films are examined. The ALD growth process and the optical properties are characterized by spectroscopic ellipsometry. The film composition is determined by Rutherford back scattering. The elemental and chemical analysis of the films before and after annealing treatment, from the c-Si/TiOx interface to the bulk, are carried out using the combination of transmission electron microscopy and energy dispersive X-ray spectroscopy. The findings of this work significantly improve the fundamental understanding of TiOx films from the growth to application, and could enable to control the films for future device developments.