Growth and characterization of nitrogen-doped C-face 4H-SiC epilayers

In this paper, nitrogen-doped 4H-Silicon carbide (SiC) epilayers are grown on 4° off-axis 〈0001¯〉 C-face 4H-SiC substrates by horizontal hot-wall chemical vapor deposition. Surface morphology of the epilayers shows a strong dependence on N2 flow, C/Si ratio and growth temperature. Surface defect densities are higher for samples grown under high C/Si ratio and high N2 flow condition. Lightly doped epilayers with low defect densities have been achieved by growing under optimized conditions. Macrostep bunching is observed on epilayers grown under high N2 flow condition. The degree of step bunching manifests a dependence on N2 flow. Possible impurity-induced step-bunching mechanism is discussed to explain the results. Lightly doped C-face 4H-SiC epilayers exhibit a site-competition effect, while heavily doped epilayers do not. Schottky barrier diodes fabricated on C-face 4H-SiC epilayers are shown to be comparable to or outperform those on Si-face epilayers.