We present experimental results regarding the growth of highly-oriented diamond films on 6H-SiC substrates using a BEN (Bias-Enhanced Nucleation) process with carbonization. A microwave plasma-assisted CVD system is used. The effect of methane concentration on the carburization step is considered. For all grown films, Raman spectra, XRD patterns, and SEM morphologies are discussed in terms of the growth conditions. Micro-Raman, SEM and XRD results show that, by lowering the CH4/H-2 ratio in the carbonization step, the Raman quality factor(f(q)) increases to approximately 90.7 % while the crystal orientation is changed from random to (I I I)-orientation.