STRUCTURAL, MECHANICAL AND TRIBOLOGICAL PROPERTIES OF PLASMA-ASSISTEDCHEMICALLY VAPOR-DEPOSITED HYDROGENATED CXN1-X-H FILMS

Amorphous hydrogenated carbon nitride (a-CxN1-x:H) films were prepared at low deposition temperatures (below 150 degrees C) using a capaciti vely coupled r.f. plasma-assisted chemical vapour deposition process s tarting from CH4-N-2 gas mixtures. Films were deposited on glass, Si a nd steel substrates which were placed on the powered and grounded elec trodes. The chemical composition of the films was analysed with electr on probe microanalysis. By varying the CK4:N-2 partial pressure ratio, the N content of the films could be varied between 0 and 13 at.% at t he powered electrode and between 0 and 35 at.% at the grounded electro de. Nanoindentation hardness measurements, film stress (bending beam t est method) and wear measurements (against a steel ball in the ball-on -disc test) on films deposited at the powered electrode demonstrate th at nitrogenation of amorphous carbon films leads to softer and less st ressed materials. These results are explained in terms of the microstr uctural properties of our films which, according to our IR absorption spectroscopy and Raman spectroscopy measurements, can be interpreted o n the basis of a familiar a-C:H cluster model.