Mechanism of hydrogen-induced crystallization of amorphous silicon

Saravanapriyan Sriraman, Sumit Agarwal, Eray S. Aydil, Dimitrios Maroudas

Research output: Contribution to journalArticle

Abstract

Hydrogenated amorphous and nanocrystalline silicon films manufactured by plasma deposition techniques are used widely in electronic and optoelectronic devices. The crystalline fraction and grain size of these films determines electronic and optical properties; the nanocrystal nucleation mechanism, which dictates the final film structure, is governed by the interactions between the hydrogen atoms of the plasma and the solid silicon matrix. Fundamental understanding of these interactions is important for optimizing the film structure and properties. Here we report the mechanism of hydrogen-induced crystallization of hydrogenated amorphous silicon films during post-deposition treatment with an H2 (or D2) plasma. Using molecular-dynamics simulations and infrared spectroscopy, we show that crystallization is mediated by the insertion of H atoms into strained Si-Si bonds as the atoms diffuse through the film. This chemically driven mechanism may be operative in other covalently bonded materials, where the presence of hydrogen leads to disorder-to-order transitions.

Original languageEnglish (US)
Pages (from-to)62-65
Number of pages4
JournalNature
Volume418
Issue number6893
DOIs
StatePublished - Jul 4 2002

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ASJC Scopus subject areas

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