Characterization and Mapping of Crystal Defect in Silicon Carbine
1) II-VI, Inc,. 20 Chapin Rd., Suite 1005, Pine Brook, NJ 07058 USA
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2) II-VI, Inc. 375 Saxonburg Blvd., Saxonburg, PA 16056 USA
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Department of Materials Science and Engineering, State
Keywords: Micropipes, Dislocations, KOH Etching, SWBXT, Optical Microscopy, Automated Defect Mapping
A method is presented for detecting, counting and mapping dislocations and micropipes in n+, undoped, and semi-insulating Silicon Carbide wafers. The technique is based on etching in molten Potassium Hydroxiode (KOH). The polish-etch regime for sample preparations has been optimized to produce etch pits, which all0ow quick and accurate analysis of their optical contrast.
Etch pits from dislocations and micropipes are detected and differentiated by an image processing system that is sensitive to the optical reflection profile of the etch pit. The instrument probes an area of ~ 800 x 600 mm2 and is capable of producing topographic maps showing distribution of dislocation and micropipe densities (MPD). The MPD scan time for 2” wafers is less than two hours per wafer. The created MPD maps are in good agreement with the contrast images produced by the Synchrotron White Beam X-Ray Topography.