Possibility of studying concentration profiles of reactive species during PACVD -hard coating- in an industrial set-up

The concentration profiles of the reactive species for plasma-enhanced chemical vapour deposition of TiN have been studied by optical emission spectroscopy (OES) in the spectral range from 300 to 800 nm. The low temperature deposition process of TiN/TiC from TiCl4 is well known in small reactors, but until now the up-scale of this process is still a challenge. As shown in the literature it is well known that the process control parameter is the concentration of reactive Ti+ in the plasma. The gas is a mixture of evaporated TiCl4, nitrogen or methane, and hydrogen as the carrier gas. The OES in combination with a handling system for the spatially resolved measurement is a tool for detection and in-situ measurement of the reactive species in large reactors. The change in the concentration of the species depends on the injection of the gas mixture into the plasma and the influence of the process parameters on the reaction. The process parameters are also connected to the deposition rate, which change the concentration of reactive particles in the plasma too. The measurements were made in a cylindrical hot-wall reactor (of 600 mm diameter and 900 mm height). The results of our measurements show the concentration profiles as function of the gas inlet system used.