Quick assessment of homogeneity in large-diameter InP substrate by mapping near-infrared transmittance

A quick imaging technique of near-infrared transmittance has been developed to assess both macroscopic and microscopic homogeneities in VCZ-grown S-doped InP substrates with the large diameters up to 4 inches. In addition to homogeneity assessment of substrates with various diameters, an asymmetric pattern, reflecting the asymmetric shape of solid-liquid interface, as well as a steep striation pattern due to fluctuation of growth speed are observe in a large diameter substrate.