Controlled oxydation of Alkyl Monolayers Grafted onto Flat Si (111) in an Oxygen Plasma of Low Power Density

Damien Aureau; Willy Morscheidt; A. Etcheberry; J. Vigneron; F. Ozanam; P. Allongue; J.-N. Chazalviel

doi:10.1021/jp903892z

Controlled oxydation of Alkyl Monolayers Grafted onto Flat Si (111) in an Oxygen Plasma of Low Power Density

Damien Aureau ¹ Willy Morscheidt ² A. Etcheberry ³ J. Vigneron ³ F. Ozanam ¹ P. Allongue ¹ J.-N. Chazalviel ¹

1 LPMC - Laboratoire de physique de la matière condensée

2 LGPPTS - Laboratoire Génie des Procédés Plasmas et Traitement de Surface

3 ILV - Institut Lavoisier de Versailles

Abstract : Alkyl monolayers anchored to an atomically flat hydrogenated (111)-oriented silicon surface through covalent SiC bonding have been submitted to an oxygen plasma treatment of controlled power density. The chemical state of the surface was monitored in situ in real time in the plasma cell using multiple-internal-reflection infrared spectroscopy and ex situ by X-ray photoelectron spectroscopy. While plasma treatments of moderate power densities (0.11 W/cm3) lead to complete removal of the organic monolayer, using very-low power densities (10 mW cm3) leads to selective oxidation of the organic chains with negligible etching of the monolayer and a very limited oxidation of the silicon surface. Successive formation of alcohol, ketone, and carboxyl functions is observed before reaching a quasi steady state on an hour time scale. Modelization of the plasma shows that the dominant reactive species at these low power densities is the singlet oxygen molecule (1Δg). A molecular-scale reaction mechanism is proposed, and a simple kinetic model is derived. A major conclusion is that reaching a quasi steady state is attributable to the very low amount of atomic oxygen in the plasma and to the densification of the layer upon incorporation of oxygen-bearing groups.

Type de document :

Article dans une revue

Journal of Physical Chemistry C, American Chemical Society, 2009, 113 (32), pp.14418-14428. 〈10.1021/jp903892z〉

Domaine :

Chimie / Chimie inorganique

Liste complète des métadonnées

https://hal-enscp.archives-ouvertes.fr/hal-00702493
Contributeur : Amélie Nadolny <>
Soumis le : mercredi 30 mai 2012 - 14:02:34
Dernière modification le : samedi 15 décembre 2018 - 01:44:06

Controlled oxydation of Alkyl Monolayers Grafted onto Flat Si (111) in an Oxygen Plasma of Low Power Density

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Controlled oxydation of Alkyl Monolayers Grafted onto Flat Si (111) in an Oxygen Plasma of Low Power Density

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