Mechanism of Improved Thermal Stability of B in Poly-SiGe Gate on SiON

Post-annealing characteristics of in situ B-doped poly-SiGe films have been investigated. Thermal stability of substitutional B atoms at a supersaturated concentration was improved by Ge doping, e.g., the stability at 800 C for poly-Si0.6Ge0.4 films was nine times as high as that for poly-Si films....

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Bibliographic Details
Published in:Japanese Journal of Applied Physics 2002-04, Vol.41 (Part 1, No. 4B), p.2468-2471
Main Authors: Sadoh, Taizoh, Kenjo, Atsushi, Miyauchi, Akihiro, Inoue, Hironori, Miyao, Masanobu
Format: Article
Language:English
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Summary:Post-annealing characteristics of in situ B-doped poly-SiGe films have been investigated. Thermal stability of substitutional B atoms at a supersaturated concentration was improved by Ge doping, e.g., the stability at 800 C for poly-Si0.6Ge0.4 films was nine times as high as that for poly-Si films. Both fast and slow processes exist for the deactivation of B. The fast process was due to movement of B atoms from substitutional to interstitial sites, enhanced by a local strain induced by the difference in atomic radii between Si and B atoms, and the slow process was due to trapping of B at grain boundaries during grain growth. The mechanism of the improved thermal stability of B atoms is discussed on the basis of local strain compensation by Ge atoms. 15 refs.
ISSN:0021-4922
1347-4065
DOI:10.1143/JJAP.41.2468