The potential of in situ lithium doping of diamond during microwave plasma chemical vapour deposition (MWPCVD) using a source of solid lithium-t-butoxide has been studied. It is shown that atomic lithium emission lines can be easily detected in the plasma by optical emission spectroscopy (OES). It was found that for a fixed fraction of the Li precursor in the feed gas a variation of the experimental conditions in the CVD reactor can drastically change the Li concentration in the plasma. The experimental results demonstrate that an optical control of the Li concentration in the plasma is indispensible. Elastic recoil detection (ERD) measurements clearly established that Li was incorporated into the diamond films in concentrations ranging from 40 up to 300 ppm. Etching of plasma exposed steel components in the reactor due to Li addition and the subsequent incorporation of iron, cobalt, and nickel into the films could be strongly reduced by replacing these components by graphite parts.    «

The potential of in situ lithium doping of diamond during microwave plasma chemical vapour deposition (MWPCVD) using a source of solid lithium-t-butoxide has been studied. It is shown that atomic lithium emission lines can be easily detected in the plasma by optical emission spectroscopy (OES). It was found that for a fixed fraction of the Li precursor in the feed gas a variation of the experimental conditions in the CVD reactor can drastically change the Li concentration in the plasma. The expe...    »