Multiwavelength Micro-Raman Characterization of Epitaxial Si1−x Ge x Layers on Si(100) and In-Line Process Monitoring Applications

Abstract

Undoped and B-doped epitaxial Si1−x Ge x layers on Si(100) were characterized using a long-focal-length, polychromator-based, multiwavelength micro- Raman spectroscopy system. The peak position and full-width at half-maximum of the Si–Si signal from Si1−x Ge x correlates very strongly with Ge content and B concentration. The intensity ratio of the Si–Si peak from the epitaxial layer to the Si peak from the substrate indicates the thickness of the epitaxial Si1−x Ge x layer. Raman characterization results were confirmed by both high-resolution x-ray diffraction and secondary-ion mass spectroscopy. Multiwavelength Raman spectroscopy was used as a practical, noncontact, in-line monitoring technique for Si1−x Ge x epitaxial processes during device manufacture.