Surfaces and Crystal Defects of Silicon

Bulk crystal defects are accessible for investigation when silicon crystals are sliced and the defects occur close to or at the surface of wafers. Such near-surface defects can then be delineated by modifying some processes used for preparing clean, polished wafers. The delineated defects usually occur as pits the shape of which depends on the delineation process used. The different shapes of the pits has consequences for their detection by light scattering techniques (laser scanners or surface inspection systems). The density of the such generated surface defects is related to the defect density in the crystal bulk and is influenced by the growth parameters. These surface defects therefore provide a means for studying and for characterizing the bulk defect density.