Surface roughness studies on 4H-SiC layers grown by liquid phase epitaxy

The surface roughness on 4H-SiC layers grown by LPE was systematically studied. The surface morphology was investigated by scanning electron microscopy and atomic force microscopy. Depending on the substrate orientation two different types of growth morphology were found: terraced and step flow growth. The height of growth steps was found to depend on the angle of the substrate off-orientation. The higher the degree of substrate off-orientation the higher the step height. The terrace height depends on the impurity concentration in LPE layers. With the decrease of the impurity level, the terrace height has been significantly decreased.