NUCLEATION OF CVD-TIN ON TUNGSTEN

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.