Homoepitaxial diamond films grown by step-flow mode in various misorientation angles of diamond substrates

Surface morphologies of device-grade homoepitaxial diamond films grown by microwave plasma chemical vapor deposition (CVD) with CH 4 /H 2 ratios and misorientation angles of diamond (001) substrates are discussed. We produced a map of surface morphologies as a function of both the misorientation angles of the diamond substrates and CH 4 /H 2 ratios. This map revealed that homoepitaxy under CH 4 /H 2 ratios greater than 0.05% was in good agreement with results reported in the literature. This could be explained in terms of migration length and CH 4 /H 2 ratios. On the other hand, when the CH 4 /H 2 ratios were lower than 0.15%, we found that the misorientation angle does not affect the surface morphology of the homoepitaxial diamond films so much, and we obtained atomically flat surfaces over the whole substrate area. The numerical result may be consistent with the fact that the migration length of precursors increases by orders of magnitude in the presence of a large amount of atomic hydrogen.