A new magic-mirror approach, that was based upon the local distortion of a perfect wave-front, was improved by using an homogeneous laser beam. Many (epi-)wafers were evaluated by using this approach, and many crystal defects and surface flaws were observed. These included some growth defects, various surface finishing flaws, and defects which were introduced during epi-growth. A phenomenon was identified in which the epilayer amplified defects in the Si substrate during the epi-growth process. The redistribution of impurities, due to defects in the substrate, was also studied.

J.Deng, Z.Li, G.Zhang, Y.Geng: Journal of Crystal Growth, 1995, 152[4], 274-9