OBSERVATIONS OF GROWTH-PROCESS OF CHEMICALLY VAPOR-DEPOSITED DIAMOND SINGLE-CRYSTAL

The growth process and morphological variations of diamond single crystals obtained by microwave plasma CVD of the CO-H2 reactant system were observed using scanning electron microscopy. The optimum conditions for spontaneous nucleation and growth of diamond on a (100) Si wafer were microwave power of 550 W, total pressure of 30-60 Torr, total flow rate of 200 ml/min and CO concentration of 5-10 vol%. Cubo-octahedral single crystals of diamond composed of {111} and {100} planes were grown epitaxially for 50 h by treating the coarse seed crystals of natural diamonds under the above growth conditions. Concave and terrace parts of the growing crystal surface were preferentially grown, resulting in the formation of symmetric single crystals. Typical trigonal pit patterns were formed on {111} planes of the developing crystal surface, while pyramidal shaped growth steps were observed on the {100} planes.