Investigation of micropipe and defects in molten KOH etching of 6H n-silicon carbide (SiC) single crystal

• Molten KOH etching of 6H n-SiC was optimized (function of time and temperature) to reveal defects.
• 500 °C was found optimum to reveal micropipe, screw, threading and basal plane dislocations.
• The etch pit and micropipe density were found ∼1×104 cm−2 and (8–10) cm−2 respectively.

Silicon carbide (SiC) is an attractive wide band gap IV–IV semiconductor material suitable for high temperature, voltage and frequency applications. However, the presence of defects and its identification is the major issue prior to using for electronic devices application. To identify the defects, an easy and quick method is highly desirable. The present study has investigated molten KOH etching of 6H n-SiC for revealing of defects as a function of temperature (400–600) °C and time. The etch pits were observed using Nomarski microscope and categorized with respect to their morphology. Result revealed that 500 °C was the optimum temperature for identification of micropipes (μP), screw dislocation (SD), threading edge dislocation (TD) and basal plane dislocation (BD). The etch pit and micropipe density were found in the range of ∼1×104 cm−2 and (8–10) cm−2 respectively. Also, the etching rate was found to obey an Arrhenius law with activation energy of (19–21) kcal/mol.

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