Optical properties of mixed phase a-C/diamond films deposited by dc magnetron sputtering of vitreous carbon target

Mixed phase a-C/diamond films were deposited on glass and fused silica substrates by de magnetron sputtering of a vitreous carbon target in argon plasma. The optical characterization of the films, deposited at zero bias voltage, (V-B=0) indicated a high band gap (E-g>3eV). E-g increased further when deposited with negative bias voltage (V-B=-100 V). The variations of stress (0.5-4 GPa) and strain (0.6x10(-3)-8x10(-3)) with deposition temperature (300 K less than or equal to T less than or equal to 573 K) were determined by a non-destructive optical technique. The hardness (H-v) of the films deposited simultaneously (at T-s similar to 573 K) on glass, fused silica and silicon substrates indicated a variation within 18-23 GPa. FTIR studies of the films deposited on Si indicated high sp(3) content(>80%) with predominant C-H stretching modes within 2800-3000 cm(-1). (C) 1997 Elsevier Science Ltd.