DIAMOND GROWTH BY HOT-FILAMENT CHEMICAL-VAPOR-DEPOSITION - STATE-OF-THE-ART

Low-pressure diamond deposition using hot-filament gas activation was the first method to achieve nucleation and continuous diamond growth o n various substrates. The method itself is simple but the strongly int erdependent parameters involved must be strictly controlled in order t o obtain reproducible diamond quality. The material used for the hot f ilament and its reactions during diamond deposition are important for gas activation. Together with this the chemical stability of the subst rate and the deposition parameters determine the quality of the diamon d layers produced. The growth conditions must be optimized for each sp ecific application. When scaling up the hot-filament method, a uniform temperature distribution and the gas flow become additional factors o f major importance for obtaining good quality diamond coating. The C: 0: H ratio in the reaction gas also influences diamond growth rates an d the resulting quality of the diamond films.