Origin Analysis and Elimination of Obtuse Triangular Defects in 4° Off 4H-SiC Epitaxy

The obtuse triangular defects would result in higher leakage currents and the preferential gate oxide breakdown of SiC devices. The formation and structural features of obtuse triangular defects on the 4° off 4H-SiC epilayers were investigated by confocal microscope and photoluminescence image. Two structrures of obtuse triangular defects were found. By optimizing the growth process, obtuse triangular defect free epitaxial layers were abtained on SiC substrate with serveral stacking fault. The number of triangular SFs defects was less than 0.5/cm2.