Preparation of nitrogen-rich CNx films with inductively coupled plasma CVDand pulsed laser deposition

Nitrogen-rich amorphous carbon nitride films with N/(N + C) greater than or equal to 0.5 have been deposited with three different methods, namely: (i) inductively coupled plasma CVD utilizing chemical transport reactions (ICP -CTR); (ii) inductively coupled plasma CVD with gaseous precursors (ICP-GP) and (iii) pulsed laser deposition (PLD) with additional r.f. plasma discha rge. By means of plasma diagnostic measurements it is shown that in each ca se high concentrations of active radical species (e.g. CN* and N*) are nece ssary to obtain high nitrogen concentrations. On the other hand, these nitr ogen-rich films turned out to be mainly sp(2) bonded having rather low dens ities of 1.8-2.0 g cm(-3) only, irrespective of the method. From a comparis on of the three techniques, and of further literature data, conclusions are drawn regarding the conditions necessary to obtain high N/(N + C) ratios, and regarding the deposition of superhard, crystalline Sp(3) bonded carbon nitride modifications. (C) 2001 Elsevier Science B.V. All rights reserved.