Study of reactions between HfO2 and Si in thin films with precise identification of chemical states by XPS |
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Authors: | H. WangP. Wu X.F. LiS. Chen S.P. ZhangB.B. Song |
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Affiliation: | School of applied science, University of Science and Technology Beijing, Beijing 100083, PR China |
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Abstract: | Reactions between HfO2 and Si in HfSiO films during deposition and post-annealing have been studied. Intermixing of HfO2 and Si is achieved by radio frequency sputtering with HfO2/Si compound targets, and post-annealing is used to promote the reaction at different temperatures. The structural characteristics of the mixture, HfSiO films, are analyzed by X-ray photoelectron spectroscopy and X-ray diffraction, and a careful assessment of chemical states is performed for precise identification. XPS results show that with ratios of Si:Hf ranging from 0 to 0.3 in HfSiO films, Si fully reacts with HfO2 to form silicate during deposition. However, SiO2 appears when the ratio of Si:Hf rises to 1.2. When the annealing temperature reaches 600 °C, decomposition of hafnium silicate is observed and hafnium silicide forms in the bulk of the films. XRD results reveal that HfSiO films remain amorphous with the annealing temperature below 600 °C but crystallize at 800 °C. |
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Keywords: | High-κ dielectrics HfSiO films X-ray photoelectron spectroscopy Interfacial reaction |
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