X-ray photoelectron spectroscopy study of high-k CeO2/La2O3 stacked dielectrics
This work presents a detailed study on the chemical composition and bond structures of CeO2/La2O3 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 decompositi...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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AIP Publishing LLC
2014-11-01
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| Series: | AIP Advances |
| Online Access: | http://dx.doi.org/10.1063/1.4902017 |
| _version_ | 1818934888357691392 |
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| author | Jieqiong Zhang Hei Wong Danqun Yu Kuniyuki Kakushima Hiroshi Iwai |
| author_facet | Jieqiong Zhang Hei Wong Danqun Yu Kuniyuki Kakushima Hiroshi Iwai |
| author_sort | Jieqiong Zhang |
| collection | DOAJ |
| description | This work presents a detailed study on the chemical composition and bond structures of CeO2/La2O3 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 CeO2 layer and a cerium-lanthanum complex oxide was formed in between the CeO2 and La2O3 films. Ce3+ and Ce4+ states always coexist in the as-deposited CeO2 film. Quantitative analyses were also conducted. The amount of CeO2 phase decreases by about 8% as approaching the CeO2/La2O3 interface. In addition, as compared with the single layer La2O3 sample, the CeO2/La2O3 stack exhibits a larger extent of silicon oxidation at the La2O3/Si interface. For the CeO2/La2O3 gate stack, the out-diffused lanthanum atoms can promote the reduction of CeO2 which produce more atomic oxygen. This result confirms the significant improvement of electrical properties of CeO2/La2O3 gated devices as the excess oxygen would help to reduce the oxygen vacancies in the film and would suppress the formation of interfacial La-silicide also. |
| first_indexed | 2024-12-20T05:11:26Z |
| format | Article |
| id | doaj.art-fadab961566743e0a574b5957bcd029e |
| institution | Directory Open Access Journal |
| issn | 2158-3226 |
| language | English |
| last_indexed | 2024-12-20T05:11:26Z |
| publishDate | 2014-11-01 |
| publisher | AIP Publishing LLC |
| record_format | Article |
| series | AIP Advances |
| spelling | doaj.art-fadab961566743e0a574b5957bcd029e2022-12-21T19:52:16ZengAIP Publishing LLCAIP Advances2158-32262014-11-01411117117117117-910.1063/1.4902017018411ADVX-ray photoelectron spectroscopy study of high-k CeO2/La2O3 stacked dielectricsJieqiong Zhang0Hei Wong1Danqun Yu2Kuniyuki Kakushima3Hiroshi Iwai4Department of Electronic Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, HONG KONGDepartment of Electronic Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, HONG KONGDepartment of Information Sciences and Electronic Engineering, Zhejiang University, Hangzhou, CHINAFrontier Research Center, Tokyo Institute of Technology, Nagatsuta-cho, Yokohama, 226-8502, JAPANFrontier Research Center, Tokyo Institute of Technology, Nagatsuta-cho, Yokohama, 226-8502, JAPANThis work presents a detailed study on the chemical composition and bond structures of CeO2/La2O3 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 CeO2 layer and a cerium-lanthanum complex oxide was formed in between the CeO2 and La2O3 films. Ce3+ and Ce4+ states always coexist in the as-deposited CeO2 film. Quantitative analyses were also conducted. The amount of CeO2 phase decreases by about 8% as approaching the CeO2/La2O3 interface. In addition, as compared with the single layer La2O3 sample, the CeO2/La2O3 stack exhibits a larger extent of silicon oxidation at the La2O3/Si interface. For the CeO2/La2O3 gate stack, the out-diffused lanthanum atoms can promote the reduction of CeO2 which produce more atomic oxygen. This result confirms the significant improvement of electrical properties of CeO2/La2O3 gated devices as the excess oxygen would help to reduce the oxygen vacancies in the film and would suppress the formation of interfacial La-silicide also.http://dx.doi.org/10.1063/1.4902017 |
| spellingShingle | Jieqiong Zhang Hei Wong Danqun Yu Kuniyuki Kakushima Hiroshi Iwai X-ray photoelectron spectroscopy study of high-k CeO2/La2O3 stacked dielectrics AIP Advances |
| title | X-ray photoelectron spectroscopy study of high-k CeO2/La2O3 stacked dielectrics |
| title_full | X-ray photoelectron spectroscopy study of high-k CeO2/La2O3 stacked dielectrics |
| title_fullStr | X-ray photoelectron spectroscopy study of high-k CeO2/La2O3 stacked dielectrics |
| title_full_unstemmed | X-ray photoelectron spectroscopy study of high-k CeO2/La2O3 stacked dielectrics |
| title_short | X-ray photoelectron spectroscopy study of high-k CeO2/La2O3 stacked dielectrics |
| title_sort | x ray photoelectron spectroscopy study of high k ceo2 la2o3 stacked dielectrics |
| url | http://dx.doi.org/10.1063/1.4902017 |
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