Raman scattering (RS) experiments have been carried out to determine
both residual strain and alloy composition in a bulk Si1−xGex
single crystal with compositional gradient, which can be used as a
focusing and diffracting X-ray monochromator. Since RS results are
influenced both by strain and by composition, it is difficult to
determine them separately from the observed phonon position.
By analyzing strain effect on RS in connection
with a strain model developed for bulk mixed
crystals, both residual strain and alloy composition are evaluated. It
is found that the alloy composition evaluated from the RS results is
in good agreement with that measured by the standard chemical analysis.
It is also found that the axial and radial strain components vary from
−0.76×10−3 to −1.2×10−3 and 3.6×10−4 to
5.7×10−4, respectively, for the almost linear variation in
composition from 0.034 to 0.055.