REACTIVE DEPOSITION OF DIAMOND AND SI CARBIDE FILMS BY HYDROGEN PLASMA-ETCHING OF GRAPHITE AND SI IN THE RF PLASMA-JET

An r.f. plasma jet with pure hydrogen, flowing through a graphite nozzle, was used to create diamond films on graphite substrates. After 60-600 min exposure of the substrate at 4 Torr to the active hydrogen flow produced in the graphite nozzle of an r.f. jet system, rapid diamond nucleation at selected parts of the substrate surface was observed. Growth of SiC(x), crystals has been observed on Si substrates under similar conditions. On the basis of comparative experiments using Si and graphite substrates two simultaneous processes can be assumed to be responsible for diamond nucleation: (i) plasma etching of the graphite nozzle by hydrogen and formation of C-H radicals which are forced by the hydrogen jet flow to the substrate, where they react with H atoms; (ii) etching of the graphite substrate by H atoms and creation of C-H radicals, which react again with H atoms at the etched surface and form sp3 diamond bonds. The first of the above-mentioned processes dominates in our experiments.