YANG Liping ¹ , YAN Kai ^{1, 2} , ZHAO Yuanyuan ² , CAO Jiangli ²
(1. Department of Chemistry, Tsinghua University, Beijing 100084, China; 2. Institute of Advanced Materials and Technology,
University of Science and Technology Beijing, Beijing 100083, China)

Abstract: The HfO₂ films were deposited on n-Si (100) substrates with native SiO₂ layer by electron beam evaporation. The effects of annealing temperature on the film-substrate interface in HfO₂ films in nitrogen atmosphere were studied by using Auger electron spectroscopy(AES), atomic force microscope (AFM), grazing incidence X-ray diffraction (GIXRD) and X-ray photoelectron spectroscopy (XPS). The results showed that the broadening of the film-substrate interface layer could be induced by the annealing temperature in nitrogen atmosphere. With the increase of the annealing temperature, the oxygen content in the film-substrate interface layer increased continuously as well as the interface width. When the temperature went higher (at 900 ºC), the width at the film-substrate interface increased about 20 nm compared with that of the as-deposited film, and the surface roughness grew to 1.047 nm from the original 0.184 nm. Meanwhile, the defect density in the HfO₂ film layer reached the maximum. An increase of oxygen content in the film-substrate interface layer could be induced by the increasing of the defect density, which led to the change in the chemical structure of the interface layer.

Key words: HfO₂ film; film-substrate interface; surface structure; structure defect; diffusion