MICROSTRUCTURE AND MECHANICAL-PROPERTIES OF A-B1-XNX-H FILMS PREPAREDBY RF PACVD

Amorphous B1-xNx:H films were prepared in a capacitively coupled r.f. plasma-assisted chemical vapour deposition reactor at deposition tempe ratures below 200 degrees C starting from N-2-B2H6 (10% in H-2) gas mi xtures. Films were deposited on Si, steel and glass substrates which w ere placed on the grounded and powered electrodes. By varying the part ial pressures of the gases, the composition parameter x was varied bet ween 0 and 0.55. Optical emission spectroscopy was used to monitor H-, B-and N-related plasma species. The film microstructure was character ized by IR spectroscopy in the wavenumber range 400-4000 cm(-1) Compre ssive film stress (bending beam method) and hardness (nanoindentation method) were measured as a function of composition and bias voltage. W ear and friction behaviours were studied under humid and dry N-2 ambie nt conditions using a ball-on-disc apparatus. A comparison between a-B :H films and a-C:H (diamond-like carbon) films reveals similar mechani cal properties but a very different wear behaviour. This result is exp lained in terms of different friction mechanisms related to the format ion of transfer layers.