Diamond films have been successfully deposited by DC thermal plasma jet CVD at a rate of 40 µm/h under atmospheric and subatmospheric pressures. Transmission electron microscopy (TEM) has been used for the characterization of the diamond films and the intermediate phase. The orientation and the distribution of β-SiC at the interface between the diamond and silicon substrate have been observed using selected-area electron diffraction with the associated dark-field images. X-ray diffraction, scanning electron microscopy, and Raman spectroscopy are used for the characterization of the produced diamond films. Potential applications of selected-area channeling patterns are discussed for investigating the correlations between the growth direction and the crystalline perfection.