Low-Temperature Halo-Carbon Homoepitaxial Growth of 4H-SiC: Morphology, Doping, and Role of HCl Additive

Abstract

Low-temperature epitaxial growth of 4H-SiC with CH3Cl carbon precursor was further developed. In-situ doping with nitrogen and aluminum was investigated. The nitrogen concentration in epitaxial layers grown on the C face was almost two orders of magnitude higher than that in the Si-face epilayers grown in the same growth run at 13000C. The opposite trend was observed for intentional aluminum doping, with more than an order of magnitude higher aluminum concentration incorporated in Si-face epilayers. High values of nitrogen and aluminum doping well in excess of 1020 cm-3 without any obvious epilayer morphology degradation can be achieved on C-face and Siface respectively. Addition of HCl during halo-carbon growth at 13000C resulted in drastic improvement of the surface morphology. Also, a significant increase of the growth rate took place confirming that the improvement in the epilayer morphology during HCl-assisted growth is predominantly related to silicon cluster etching by additional Cl-containing vapor species.