The effect of initial growth condition of 3C-SiC growth on the C-face of 6H-SiC has been studied in sublimation epitaxy. The initial temperature increase to initiate the sublimation has a strong effect on the polytype formation using on-axis substrates. Polytype inclusions of 6H-SiC in the 3C-SiC layers is found to be related to spiral growth. The micropipe dissociation process is discussed. At the slowest ramp-up of the temperature the 3C-SiC does not contain any inclusions. In 1 degree off-oriented substrates there were no 3C-SiC formation. In this case the different ramp-up conditions has an influence on the heights of the steps.