Diamond films have been grown on polished Si substrates seeded with
nanocrystalline diamond powder colloid using hot-filament chemical vapour
deposition. Instead of using the conventional gaseous carbon source, a carbonized
W filament was used as the carbon source. The only feeding gas was hydrogen.
Compared with those produced by traditional methods, the polycrystalline
diamond grown by this new method has smaller grain size. The growth
mechanism is also discussed.