For CoCr based perpendicular media, many trials have been reported to reduce the initial growth region in magnetic layer by using epitaxial growth technique with a Cr-rich CoCr intermediate layer. Recently it has been reported that CoCr intermediate layer with very thin carbon layer with a thickness less than 1 nm is significantly effective to improve perpendicular magnetic properties for CoCr-based perpendicular recording media. However, the role of very thin carbon layer for the microstructure of the film has not been clarified yet. In this paper, we present the mechanism of film growth of CoCr intermediate layer and CoCrPtB magnetic layer by analyzing the thickness dependence of in-plane XRD profiles and the perpendicular magnetic anisotropy. The media used in the analysis was Co69Cr19Pt8B4/Co60Cr40/C(1nm)/Ti(25nm) media (dmag=30nm, Hc=3.5kOe, and S=0.89), compared with the media without C layer.