Investigation of TiN deposition in different sized PACVD reactors by means of optical emission spectroscopy

The TiN-PACVD process by pulsed d.c. plasma in a TiCl4/N2/H2/Ar gas mixture is investigated. The emission spectra are measured in dependence on the discharge conditions like reactor size (30 l, 200 l, 500 l), current density (0,072-0.98 mA/cm²) and N2/H2 gas inlet ratio (0.03-1.07). It is possible to carry out spatially resolved measurements in the small reactor in the cathode region. Ti+, N2, N2+, H, Ar and Ar+ lines are observed. A Ti+ line emission is only observed in the cathode glow, the emission of the other species are also detected in the negative glow. The spatial intensity distribution of the emission of the various species is different. Scanning electron microscopy and glow discharge optical emission spectroscopy measurements were carried out to investigate the layer properties. The growth rate and the film morphology mainly depend on the current density. The layer composition (Ti/N~1) only changes by essential small N2 admixtures.