Optimisation of the MOCVD of Ti(C, N) in a pulsed H-2-N-2 plasma by gas-phase analysis

Favourable gas-phase conditions for the deposition of Ti(C,N) in a large sc ale reactor vessel have been determined by a mass spectroscopic study of th e activation of tetrakis(dimethylamino)titanium (TDMAT) and tetrakis(diethy lamino)titanium (TDEAT) in a mixed H-2-N-2, pulsed DC plasma. Activated hyd rogen seemingly attacks the M-L bond. At least part of the ligands are stri pped from the Ti atom. This prevents hydrocarbon incorporation in the coati ng. However, no nitrogen remains available for the formation of TiN. Additi on of N-2 to a H-2 plasma seems to result in transamination. Transamination by NHx (1 less than or equal to x less than or equal to 4) in a H-2-N-2 pl asma appears to be a very attractive mechanism for cleavage of ligands and nitrogen supply at low temperatures. Deposition under preferred conditions produced bronze adherent coatings. The hardness varied between 1600 and 230 0 kgf/mm(2) on stainless steel and tungsten carbide. The coatings are very ductile and night improve wear resistance of tools in non-lubricating forgi ng processes.