Raman study of polish-induced surface strain in 〈100〉 GaAs and InP

We report measurements of the first-order Raman spectra of the longitudinal optic phonon from 〈100〉 surfaces of GaAs and InP which have been polished by various procedures. Nondestructive depth profiling was accomplished by using the various excitation lines of an Ar+ laser. The resultant line shape changes have been quantitatively accounted for by a model based on the convolution of the penetration depth of the light and the skin depth of the polish-induced surface strain. We find the polish-induced surface strain to be compressive and about 4% in GaAs and 5% in InP, relatively independent of particle size. The strain skin depth is substantially less than the particle size although it does increase with increasing size and polishing time.