Compositional analysis of SiOxNy:H films by heavy-ion ERDA: the problem of radiation damage

• Published in: Surface and interface analysis 2002-08, Vol.34 (1), p.749-753
• Main Authors: Bohne, W., Fuhs, W., Röhrich, J., Selle, B., Sieber, I., del Prado, A., San Andrés, E., Mártil, I., González-Díaz, G.
• Format: Article
• Language: English
• Subjects: Composition and phase identification; Condensed matter: structure, mechanical and thermal properties; elastic recoil detection analysis; electron cyclotron resonance plasma deposition; Exact sciences and technology; hydrogen content; infrared spectroscopy; ion beam damage; Ion radiation effects; Physical radiation effects, radiation damage; Physics; silicon oxynitride; Structure of solids and liquids; crystallography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology
• ISSN: 0142-2421; 1096-9918
• DOI: 10.1002/sia.1403

Films of SiOxNy:H were deposited at room temperature on Si substrates by the electron cyclotron resonance (ECR) plasma method. By varying the flow rates of the precursor gases SiH4, O2 and N2, the whole composition range between pure silicon oxide and nitride could be covered. Heavy‐ion elastic recoil detection analysis (HI‐ERDA) with a 150 MeV 86Kr ion beam and time‐of‐flight (ToF) mass separation was applied to determine the absolute atomic concentrations of all film components, including hydrogen. Additionally, the bonding configuration of the films was studied by infrared (IR) spectroscopy. Extended ion beam exposure was found to decrease the intensity of the N–H phonon band as well as the nitrogen and hydrogen concentrations. By storing the ion scattering data event by event and by recalculating a zero‐dose composition, this effect was taken into account. The corrected HI‐ERDA results revealed clear relations to the deposition parameters (e.g. the O2/SiH4 flow ratio). The hydrogen incorporated in the films turned out to be bonded predominantly to nitrogen. The damage effects were strongest in the medium composition range. They were found to scale with the relative concentration of SiO2N2‐type basic tetrahedrons, suggesting that this bonding configuration is most sensitive against irradiation during the HI‐ERDA measurement. Copyright © 2002 John Wiley & Sons, Ltd.