  The Raman spectra on the cleaved surface of La$_{2-x}$Sr$_x$CuO$_4$ is found
to be different from those on the mechanically polished or chemically etched
surface. On the cleaved surface, the step-like increase of the scattering
intensity below 700 cm$^{-1}$ is washed away and the two-phonon peaks are
preserved clearly even at the optimum doping. The difference is demonstrated on
the optimally doped crystal at x=0.15 and the stripe phase crystal at x=0.115.
The stripe phase is stabilized by defects induced by mechanical polishing.
