EFFECTS OF ORGANOMETALLIC COMPOUNDS INTRODUCED TO PLASMA ON DIAMOND SYNTHESIS

Volatile organometallic compounds were introduced to feed gas (CH4/H2) during the synthesis of diamond by microwave plasma chemical vapor deposition. Addition of Si(CH3)4, Sn(CH3)4, Sn(CH3)4, Fe(AA)3, Tio(AA)2 or Zr(AA)4 increased nucleation density of diamond particles to 2-10 times that without additives. Addition of Zr(AA)4 and TiO(AA)2 made the grain sizes smaller. Most additives lowered atomic hydrogen temperature, increased concentration Of C2 in plasma and seemed therefore to degrade the crystallinity of the diamonds. Some additives shifted the A band cathodoluminescence to a higher energy region. In the case of Si(CH3)4, the GR-1 center cathodoluminescence was observed as well as the A-band, and adhesion of the diamond film was markedly improved.