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Title: X-ray photoelectron spectroscopy study of high-k CeO{sub 2}/La{sub 2}O{sub 3} stacked dielectrics

This work presents a detailed study on the chemical composition and bond structures of CeO{sub 2}/La{sub 2}O{sub 3} stacked gate dielectrics based on x-ray photoelectron spectroscopy (XPS) measurements at different depths. The chemical bonding structures in the interfacial layers were revealed by Gaussian decompositions of Ce 3d, La 3d, Si 2s, and O 1s photoemission spectra at different depths. We found that La atoms can diffuse into the CeO{sub 2} layer and a cerium-lanthanum complex oxide was formed in between the CeO{sub 2} and La{sub 2}O{sub 3} films. Ce{sup 3+} and Ce{sup 4+} states always coexist in the as-deposited CeO{sub 2} film. Quantitative analyses were also conducted. The amount of CeO{sub 2} phase decreases by about 8% as approaching the CeO{sub 2}/La{sub 2}O{sub 3} interface. In addition, as compared with the single layer La{sub 2}O{sub 3} sample, the CeO{sub 2}/La{sub 2}O{sub 3} stack exhibits a larger extent of silicon oxidation at the La{sub 2}O{sub 3}/Si interface. For the CeO{sub 2}/La{sub 2}O{sub 3} gate stack, the out-diffused lanthanum atoms can promote the reduction of CeO{sub 2} which produce more atomic oxygen. This result confirms the significant improvement of electrical properties of CeO{sub 2}/La{sub 2}O{sub 3} gated devices as the excess oxygenmore » would help to reduce the oxygen vacancies in the film and would suppress the formation of interfacial La-silicide also.« less
Authors:
 [1] ;  [1] ;  [2] ;  [3] ; ;  [4]
  1. Department of Electronic Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong)
  2. (China)
  3. Department of Information Sciences and Electronic Engineering, Zhejiang University, Hangzhou (China)
  4. Frontier Research Center, Tokyo Institute of Technology, Nagatsuta-cho, Yokohama, 226-8502 (Japan)
Publication Date:
OSTI Identifier:
22420159
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 4; Journal Issue: 11; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CERIUM; CERIUM IONS; CERIUM OXIDES; CHEMICAL BONDS; CHEMICAL COMPOSITION; COMPARATIVE EVALUATIONS; DECOMPOSITION; DEPOSITS; ELECTRICAL PROPERTIES; FILMS; INTERFACES; LANTHANUM; LANTHANUM COMPLEXES; LANTHANUM OXIDES; OXIDATION; OXYGEN; PHOTOEMISSION; SILICIDES; SILICON; X-RAY PHOTOELECTRON SPECTROSCOPY