In the CVD process, a gas mixture is supplied into the reaction chamber which forms the solid matter by means of a chemical reaction at increased temperature and which is deposited on the base material under the catalytic effect of the substrate surface. There are several variants for this process; a distinction is made for example between thermal CVD processes and plasma-activated CVD (PA-CVD). The major reaction types in the first-named process are chemo-synthesis, pyrolysis, and disproportionation. In the PA-CVD process, a plasma activates the chemical reactions. In addition to the name PACVD, English literature also uses the term PE-CVD (PECVD, plasma enhanced CVD).