Post-Growth Reduction of Basal Plane Dislocations by High Temperature Annealing in 4H-SiC Epilayers

Abstract

Basal Plane Dislocations (BPD) were reduced in 4H-SiC epilayers by high temperature annealing in the range of 1600 °C to 1950 °C using two annealing techniques. Samples annealed at > 1750 °C showed almost complete elimination of BPDs propagating from the substrate. However, surface morphology was degraded for MW annealed samples above 1800 °C, with new BPDs being generated from the surface. A new capping technique was developed along with application of high N2overpressure to preserve the surface morphology and avoid formation of new BPDs.