Comparative Analysis of Defect Characteristics in Silicon Carbide Wafers of Different Grades.

In this study, two different grades of wafers, production grade and dummy grade, were employed for defect comparison. Wet etching with KOH was utilized to reveal defects on the surface of silicon carbide wafers. Optical microscopy and laser scanning confocal microscopy were employed for analysis, enabling an exploration of the performance differences between wafers of the two grades. The surface topography and etch pit profile depth were analyzed and discussed to evaluate the quality of wafers of each grade. The surface topography analysis reveals that production-grade wafers exhibit significantly fewer defects, and the types of defect differ between the two grades. Dummy-grade wafers display four defect types, micropipe (MP), threading screw dislocation (TSD), threading edge dislocation, and basal plane dislocation, whereas production-grade wafers have only two defect types, TSD and MP. Additionally, the etch pit depth serves as a criterion for classifying the four defect types. When the dimensions of surface shape and profile depth are similar, the location of the pit bottom within the profile can also be used as a judgment criterion. [ABSTRACT FROM AUTHOR]