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Towards multiscale modeling of Si nanocrystals LPCVD deposition on SiO2: From ab initio calculations to reactor scale simulations

Zahi, Ilyes and Vergnes, Hugues and Caussat, Brigitte and Estève, Alain and Djafari Rouhani, Mehdi and Mur, Pierre and Blaise, Philippe and Scheid, Emmanuel Towards multiscale modeling of Si nanocrystals LPCVD deposition on SiO2: From ab initio calculations to reactor scale simulations. (2007) Surface and Coatings Technology, 201 (22-23). 8854 -8858. ISSN 0257-8972

(Document in English)

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Official URL: http://dx.doi.org/10.1016/j.surfcoat.2007.04.127


A modeling study is presented involving calculations at continuum and atomistic (DFT, Density Functional Theory) levels so as to better understand mechanisms leading to silicon nanocrystals (NC) nucleation and growth on SiO2 silicon dioxide surface, by Low Pressure Chemical Vapor Deposition (LPCVD) from silane SiH4. Calculations at the industrial reactor scale show that a promising way to improve reproducibility and uniformity of NC deposition at short term could be to increase deposition time by highly diluting silane in a carrier gas. This dilution leads to a decrease of silane deposition rate and to a marked increase of the contribution to deposition of unsaturated species such as silylene SiH2. This result gives importance to our DFT calculations since they reveal that only silylene (and probably other unsaturated species) are involved in the very first steps of nucleation i.e. silicon chemisorption on silanol Si–OH or siloxane Si–O–Si bonds present on SiO2 substrates. Saturated molecules such as silane could only contribute to NC growth, i.e. chemisorption on already deposited silicon bonds, since their decomposition activation barriers on SiO2 surface are as high as 3 eV.

Item Type:Article
Additional Information:Thanks to Elsevier editor. The definitive version is available at http://www.sciencedirect.com The original PDF of the article can be found at Surface and Coatings Technology website : http://www.sciencedirect.com/science/journal/02578972
HAL Id:hal-03594387
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
French research institutions > Commissariat à l'Energie Atomique et aux énergies alternatives - CEA (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Laboratory name:
Deposited On:27 Oct 2008 10:53

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