Thermal-hydrogen promoted selective desorption and enhanced mobility of adsorbed radicals in silicon film growth.
Car-Parrinello simulations and static density-functional theory calculations reveal how hydrogen promotes growth of epitaxial, ordered Si films in plasma-enhanced chemical vapor deposition at low-temperature conditions where the exposed Si(001)-(2x1) surface is fully hydrogenated. Thermal H atoms, indeed, are shown to selectively etch adsorbed silyl back to the gas phase or to form adsorbed species which can be easily incorporated into the crystal down to T approximately 200 degrees C and start diffusing around T approximately 300 degrees C. Our results are well consistent with earlier experiments.
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L-NESS and Dipartimento di Scienza dei Materiali della Università degli Studi di Milano-Bicocca, Via Cozzi 53, I-20125 Milano, Italy.
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Bernasconi
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Miglio
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