Review of laser scanning tomography in S, Sn and Fe doped InP and study of scattering defects in Fe doped InP

The authors review the quality of doped substrates which are commercially available at the present time, from the viewpoint of the scattering defects. Three types of dopants, S, Sn, and Fe have been studied. The samples come from four different providers. Laser scattering tomography was used to obtain the patterns of scattering defects. Quantitative results are calculated from the tomographic images: the densities of the different types of defects, the uniformity and the average scattering level of the defects distribution. InP materials now available are quite homogeneous from the viewpoint of scattering defects. The homogeneity is found to be the best in S doped and Sn doped materials. But it is in the Fe doped that the level of scattering is the smallest