NUCLEATION OF CVD-TIN ON TUNGSTEN

Using Chemical Vapor Deposition (CVD), TiN was deposited on sharp tungsten needles. The reactant gases were TiCl4, N2, and H-2. A Transmission Electron Microscopy (TEM) investigation revealed that the first nuclei of the CVD-TiN coating on tungsten did not consist of delta-TiN, but were a mixture of alpha-TiN and epsilon-TiN. These results were also verified with x-ray measurements. From these experimental results a possible mechanism for the initial growth of TiN on tungsten is suggested. It may be that the change in relative concentrations of the different 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 consists of a metal with catalytic properties.