A scanning defect-mapping system for large-area silicon substrates

An optical scanning system has been developed that can produce maps of the spatial distributions of defects in polycrystalline silicon substrates. This instrument can operate in either the dislocation mapping mode or the grain boundary (GB) mode. In the “dislocation mode,” the optical scattering from the etch pits is used to statistically count dislocations in large-area substrates. In the “grain boundary mode,” the system recognizes local scattering from the GBs to generate grain boundary maps. The information generated by this instrument is valuable for material QA, identifying mechanisms of defect generation, the nature of thermal stresses during the crystal growth, and the solar cell process design