Using Chemical Vapor Deposition (CVD), TiN was deposited on sharp tung
sten needles. The reactant gases were TiCl4, N2, and H-2. A Transmissi
on Electron Microscopy (TEM) investigation revealed that the first nuc
lei of the CVD-TiN coating on tungsten did not consist of delta-TiN, b
ut were a mixture of alpha-TiN and epsilon-TiN. These results were als
o verified with x-ray measurements. From these experimental results a
possible mechanism for the initial growth of TiN on tungsten is sugges
ted. It may be that the change in relative concentrations of the diffe
rent titanium nitrides suggested as mechanism of the initial growth of
CVD-TiN can be applied in general for all TiCl4/H-2/N2/metal systems
where the original substrate surface material partly or completely con
sists of a metal with catalytic properties.