Quantification of substitutional and interstitial carbon in thin SiGeC films using in-line X-ray-photoelectron spectroscopy

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Vol. 11; no. 26; pp. 8935 - 8941
• Main Authors: Vives, Jeremy, Verdier, Stephane, Deprat, Fabien, Frauenrath, Marvin, Duru, Romain, Juhel, Marc, Berthome, Gregory, Chaussende, Didier
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 06.07.2023
• Subjects: Carbon; Carbon content; Chemical Sciences; Condensed Matter; Epitaxial growth; Ions; Material chemistry; Materials Science; Photoelectrons; Physics; Secondary ion mass spectrometry; Thin films; X ray photoelectron spectroscopy
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/d3tc01107k

One of the most important questions concerning the epitaxial growth of Si 1− y C y or Si 1− x − y Ge x C y is the ratio of carbon incorporated into substitutional and interstitial sites, which is highly dependent on growth conditions. Usually, the quantification of the total ( C tot ), the substitutional ( C sub ) and the interstitial ( C int ) carbon concentrations is achieved using a combination of secondary-ion mass spectrometry and X-ray-diffraction, based on careful calibration and appropriate preparation. In this study, we demonstrate the potential of non-destructive, in-line X-ray photoelectron spectroscopy to obtain the quantification of both C sub and C int in a single measurement. For substitutional carbon atoms, the XPS C 1s signal intensity increases proportionally with the carbon content, with a characteristic peak at 284.00 eV. When carbon is incorporated into interstitial sites, a shift of the C 1s peak towards lower binding energies is detected. Moreover, a broadening of the peak is observed, due to the appearance of a characteristic peak at 283.30 eV. Here, we describe the development of a measurement procedure and provide a critical discussion on the possible sources of error. Finally, an excellent correlation between the newly developed XPS quantification and the standard XRD/SIMS method is demonstrated. Original approach to detect and quantify carbon atoms located in different chemical states in SiGeC films using X-ray photoelectron spectroscopy.