Characterization and Mapping of Crystal Defects in Silicon Carbide

A method is presented for detecting, counting and mapping micropipes and dislocations in n+, undoped, and semi-insulating Silicon Carbide wafers. The technique is based on etching in molten Potassium Hydroxide (KOH), and it employs image processing that automatically detects etch pits, discriminates between micropipes and dislocations, and generate micropipe and dislocation density maps. We demonstrate a novel way of detecting and mapping dislocations and micropipes in semi-insulating SiC. This is achieved by combining a properly tuned etching technique that reliably produces well defined etch pits with image processing that enables quick and accurate analysis of the etch pit contrast. We show that the results of optical evaluation are close to those obtained using the Synchrotron White Beam X-Ray Topography (SWBXT) technique.