Photoreflectance Spectroscopy Measurements used to Determine GaAs Surface Polish Perfection

A preliminary study has been conducted to determine the feasibility of photoreflectance spectroscopy measurements to determine the polish perfection on GaAs wafers. Photoreflectance is effective in nondestructively measuring residual surface damage on wafers with widely varying polishes. Differences in the differential reflectance lineshape at the fundamental gap energy have been correlated with photon backscatter measurements that are presently used in noting GaAs polish damage. Samples of polish perfection are reported and compared with x-ray rocking curve measurements.