CARBON NITRIDE THIN-FILMS PREPARED BY REACTIVE RF MAGNETRON SPUTTERING

Nitrogenated amorphous carbon thin films (CNx) were prepared by reacti ve r.f. magnetron sputtering from a graphite target in a nitrogen cont aining plasma (up to 4.4 at%) on Si substrates. All main controllable deposition conditions (such as base and deposition pressure, power at target, target-substrate distance, substrate bias voltage) were kept c onstant throughout the series of experiments and the only variable par ameter was the nitrogen flux (0-2 seem). Iii situ spectroscopic ellips ometry (SE) in the energy region 1.5-5.5 eV in combination with Brugge man's effective medium theory analysis was used per iterative depositi on layer to monitor the Elm thickness and diamond character. The C:N c hemical bonding characteristics of the films were also examined with t he new Fourier transform IR ellipsometry technique. It was found that the films have a mixed character composed of constituents (phases) of sp(3) and sp(2) type bonding. The film composition in terms of sp3, sp (2) and void concentration as a function of film thickness and nitroge n concentration in the plasma was determined. The plasma nitrogen conc entration seems to directly affect the film deposition rate and diamon d character of the films by favoring sp(3) bond formation. (C) 1998 El sevier Science Ltd. All rights reserved.