Characterization of Interstitial-Related Bulk Defects in p~- Silicon Substrates by Epitaxial Deposition

摘要

Epitaxial deposition on a p" substrate that contains an A-swirl region results in characteristic defects, "warts". Transmission electron microscopy (TEM) shows that the warts are related to dislocation loops, i.e. to the A-swirls. From Burgers vector analysis it follows that the loops contain on the order of 10~9 silicon self-interstitials. Comparison of the area density (ⅰ) of so-called large-pits (l-pits) on the Secco etched substrate, (ⅱ) of warts after epitaxial deposition and (ⅲ) of defects after epitaxial deposition followed by Secco etching suggests that the light scattering cross section of warts is smaller, the lower the number of interstitials in the substrate defect that causes the wart. A model is proposed to explain the differences in the area density of l-pits on the Secco etched substrate and of defects after epitaxial deposition followed by Secco etching. The model allows one to roughly estimate the number of silicon self-interstitials per A-swirl defect for comparison with the TEM results. Reasonable agreement is found taking into account the large experimental error associated with of TEM observations on a relatively low number of defects.