The HfO2 films were deposited on SiO2 (native)/n-Si (100) substrates by electron beam evaporation (EBE) technology. The structural evolution of the films during thermal annealing were studied by using grazing incidence X-ray diffraction (GIXRD), Raman spectra and Auger electron spectroscopy (AES), while the change of bonding structure and interface products were obtained by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The existence of oxygen vacancies in the surface layer of the as-deposited HfO2 film was confirmed by Auger line shapes, which could facilitate the adsorption of ambient oxygen on the free surface and induce the diffusion of oxygen atoms to the surface layer during thermal annealing. Meanwhile, the newly formed defects in the films could provide more passageways for the diffusion of oxygen atoms to the film-substrate interface layer. The oxygen that diffused to the interface layer was the key factor of the change in the interface structure, which participated in the interface reaction. In addition, the formation amount and bonding structure of the interface products such as suboxide of silicon and hafnium silicate were influenced by the oxygen concentration of the external environment. (C) 2016 Elsevier B.V. All rights reserved.