AMORPHOUS-CARBON FILMS RICH IN DIAMOND DEPOSITED BY MAGNETRON SPUTTERING

In this work evidence is presented that unhydrogenated amorphous carbo n films approaching diamond can be deposited by rf magnetron sputterin g at room temperature. In situ spectroscopic ellipsometry (SE) studies , performed in the energy range 1.5-5.5 eV, have been used to monitor and characterize the films during deposition, as well as to define the range of deposition conditions which produce films rich in sp(3) C-C bonds. The internal stress developed in these films during deposition was also measured by the cantilever laser technique. A strong dependen ce was found between the sp(3) volume fraction, calculated by analyzin g the SE data, and the internal stress in the films. The effects of bi as voltage and thickness on the film stress were also examined and are discussed. It was finally observed that films beyond a critical thick ness and with an internal stress level above 6-7 GPa became metastable when exposed to air at atmospheric pressure. (C) 1997 Elsevier Scienc e S.A.