Non-contact, non-destructive characterization of Ge content and SiGe layer thickness using multi-wavelength Raman spectroscopy

Design and performance of a newly developed multi-wavelength, micro Raman spectroscopy system for non-contact and non-destructive characterization of semiconductor materials are introduced. The thickness and Ge content of Si_1-xGe_x/Si were estimated from the multi-wavelength Raman measurement results and compared to those values obtained from X-ray diffraction (XRD) and X-ray reflectance (XRR) measurements for cross-reference. Both the thickness and Ge content of Si_1-xGe_x/Si measured by Raman spectroscopy and X-ray techniques are in excellent agreement. In addition to the non-contact and nondestructive nature of Raman spectroscopy, the multi-wavelength excitation capability of the system, with high spectral and spatial resolution, are very attractive and powerful for characterization of advanced semiconductor materials, such as Si_1-xGe_x/Si and strained Si, and process optimization.