Characterization of uni-axially stressed Si and Ge concentration in Si1-xGex using polychromator-based multi-wavelength Raman spectroscopy

The design concept of a polychromator-based multi-wavelength Raman spectroscopy system (MRS-300) which is designed to overcome the common issues with conventional Raman measurement systems is described. The system is specially designed for non-destructive, material and process characterization applications in the semiconductor industry. The performance of the MRS-300 system and non-destructive nature of the tests of lattice stress/strain and Ge content were demonstrated using mechanically stressed Si samples and epitaxially grown Si_1-xGe_x samples. The capability of very high measurement resolution (0.105 cm^-1/pixel or better), accuracy repeatability (0.05 cm^-1 or better) and repeatability (0.05 cm^-1 or better) of the system were demonstrated at all three excitation wavelengths (457.9 nm, 488.0 nm and 514.5 nm). Possibility of MRS-300 applications as an in-line process monitoring system was also introduced with an example of long term measurement stability and repeatability data.