A comparative study of micropipe decoration and counting in conductive and semi-insulating silicon carbide wafers

Micropipes are considered to be one of the most serious defects in silicon carbide (SiC) wafers affecting device yield. Developing a method to count and map micropipes accurately has been a challenging task. In this study, the different etching behavior of conductive and semi-insulating wafers in molten potassium oxide (KOH) is compared. Micropipes and closed-core screw dislocations exhibit different morphology after etching and can be easily distinguished with a polishing process. Based on a new sample preparation procedure and a digital imaging technique, a novel method of efficiently and reliably mapping and counting micropipes in both conductive and semi-insulating SiC wafers is developed.