The CH4/H-2 ratio (growth rate) dependence of B-doped (I 1 1) homoepitaxial diamond film quality was investigated in the region of CH4/H-2, ratio <= 1% and 10 ppm B2H6/H-2 ratio in terms of surface morphology, crystallinity, incorporation of impurities and electrical and optical properties. It was found that there are two different growth regimes, which depend on CH4/H2 ratio, in B-doped (I 1 1) film growth. In the region of low CH4/H-2 ratio growth <= 0.25%, as CH4/H-2 ratio increased, film quality was improved in spite of the same incorporation efficiency. This result is different from that of (0 0 1) diamond film growth. On the other hand, for high (>= 0.5%) CH4/H-2 ratio growth, significant deterioration in the film quality was observed. Differences between (I 1 1) and (0 0 1) in B-doped film growth are discussed. (c) 2006 Elsevier B.V. All rights reserved.