ABSTRACT
Photoreflectance (PR) has been employed to characterize semi-insulating InP substrates from various vendors. The PR spectra taken at 82 K near the band gap were found to be explainable by the exciton ionization model. The spectra were used to estimate the surface electric field and the surface Fermi level of the substrates at room temperature. The phase of the PR line shape was found to depend on the bulk resistivity of the substrate. A simple physical model is used to explain this dependence, and a method for quantitatively determining resistivity was used to determine resistivity homogeneity throughout a boule and on a substrate. The PR line shape exhibited sensitivity to surface polishing damage and the damage depth was quantified.
