Significant Enhancement of the Dielectric Constant through the Doping of CeO2 into HfO2 by Atomic Layer Deposition |
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| Authors: | Woo‐Hee Kim Min‐Kyu Kim Il‐Kwon Oh Wan Joo Maeng Taehoon Cheon Soo‐Hyun Kim Atif Noori David Thompson Schubert Chu Hyungjun Kim |
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| Affiliation: | 1. School of Electrical and Electronic Engineering, Yonsei University, , Seoul, 120‐749 Korea;2. Process Development Team, System LSI Division, Samsung Electronics, , Yongin‐City, Gyeonggi‐Do, 446‐711 Korea;3. Department of Materials Science and Engineering, University of Wisconsin‐Madison, , Madison, Wisconsin, 53706;4. School of Materials Science and Engineering, Yeungnam University, , Gyeongsan‐si, 712‐749 Korea;5. Applied Materials, , Sunnyvale, California, 94085 |
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| Abstract: | Films of CeO2 were deposited by atomic layer deposition (ALD) using a Ce(mmp)4 mmp = 1‐methoxy‐2‐methyl‐2‐propanolate] precursor and H2O reactant. The growth characteristics and film properties of ALD CeO2 were investigated. The ALD CeO2 process produced highly pure, stoichiometric films with polycrystalline cubic phases. Using the ALD CeO2 process, the effects of Ce doping into an HfO2 gate dielectric were systematically investigated. Regardless of Ce/(Ce + Hf) composition, all ALD CexHf1?xO2 films exhibited constant growth rates of approximately 1.3 Å/cycle, which is essentially identical to the ALD HfO2 growth rates. After high‐temperature vacuum annealing at 900°C, it was verified, based on X‐ray diffraction and high‐resolution cross‐sectional transmission electron microscopy results, that all samples with various Ce/(Ce + Hf) compositions were transformed from nanocrystalline to stabilized cubic or tetragonal HfO2 phases. In addition, the dielectric constant of the CexHf1?xO2 films significantly increased, depending on the Ce doping content. The maximum dielectric constant value was found to be nearly 39 for the Ce/(Ce + Hf) concentration of ~11%. |
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