Reduction of Triangular Defects on 100mm 4° off-axis 4H-SiC using a Chloride Based CVD process

Homoepitaxial layers were grown with very low surface roughness on 4", 4˚ off-axis substrates, but a new kind of large obtuse angled triangular defect that spanned 1000-2000 μm was observed. Process changes resulted in reduction of the size and concentration of these triangular defects from 3.5cm -2 to 0.13cm -2 . Both large and small triangular defects were found to have a similar core structure. No degradation in the epitaxial morphology or quality was seen due to the process change. JBS diodes fabricated on wafers with large triangular defects had much higher leakage when the triangular defects were present in the active area of the diodes.