title: Etching and Chemical Control of the Silicon Nitride Surface.
abstract: Silicon nitride is used for many technological applications, but a quantitative knowledge of its surface chemistry is still lacking. Native oxynitride at the surface is generally removed using fluorinated etchants, but the chemical composition of surfaces still needs to be determined. In this work, the thinning (etching efficiency) of the layers after treatments in HF and NH4F solutions has been followed by using spectroscopic ellipsometry. A quantitative estimation of the chemical bonds found on the surface is obtained by a combination of infrared absorption spectroscopy in ATR mode, X-ray photoelectron spectroscopy, and colorimetry. Si-F bonds are the majority species present at the surface after silicon nitride etching; some Si-OH and a few Si-NHxbonds are also present. No Si-H bonds are present, an unfavorable feature for surface functionalization in view of the interest of such mildly reactive groups for achieving stable covalent grafting. Mechanisms are described to support the experimental results, and two methods are proposed for generating surface SiH species: enriching the material in silicon, or submitting the etched surface to a H2plasma treatment.
authors.affiliation: Laboratoire de Physique de la Matière Condensée, Ecole Polytechnique, CNRS, Université Paris-Saclay , 91128 Palaiseau, France.|Saint-Gobain Recherche , 39 quai Lucien Lefranc, 93303 Aubervilliers, France.
authors.forename: Marine
authors.initials: M
authors.lastname: Brunet
authors.affiliation: Institut Lavoisier, UVSQ-CNRS UMR 8180 , 78035 Versailles, France.
authors.forename: Damien
authors.initials: D
authors.lastname: Aureau
authors.affiliation: Laboratoire de Physique de la Matière Condensée, Ecole Polytechnique, CNRS, Université Paris-Saclay , 91128 Palaiseau, France.
authors.forename: Paul
authors.initials: P
authors.lastname: Chantraine
authors.affiliation: Saint-Gobain Recherche , 39 quai Lucien Lefranc, 93303 Aubervilliers, France.
authors.forename: François
authors.initials: F
authors.lastname: Guillemot
authors.affiliation: Institut Lavoisier, UVSQ-CNRS UMR 8180 , 78035 Versailles, France.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Etcheberry
authors.affiliation: Laboratoire de Physique de la Matière Condensée, Ecole Polytechnique, CNRS, Université Paris-Saclay , 91128 Palaiseau, France.
authors.forename: Anne Chantal
authors.identifier: http://orcid.org/0000-0002-7477-9200
authors.initials: AC
authors.lastname: Gouget-Laemmel
authors.affiliation: Laboratoire de Physique de la Matière Condensée, Ecole Polytechnique, CNRS, Université Paris-Saclay , 91128 Palaiseau, France.
authors.forename: François
authors.initials: F
authors.lastname: Ozanam
keywords: FTIR spectroscopy; XPS; etching; silicon nitride; surface chemistry