ENERGETIC CARBON DEPOSITION AT OBLIQUE ANGLES

Carbon is energetically deposited by pulsed laser vaporization, cathodic arc and ion beam sputtering to provide amorphous diamond films with varying degrees of diamondlike quality. Laser and arc films prepared at normal particle incidence are high in sp3 content and electrical resistivity, and exhibit optical behavior comparable to diamond. As the incident angle of the depositing species becomes increasingly oblique, the diamondlike character is progressively degraded. This is verified by decreases in sp3 fraction, resistivity, and optical transmittance. These changes are accompanied by a roughening of the microstructure, but no apparent variation in the transmission electron diffraction pattern. For deposition at the most oblique angles, the development of biaxial stress anisotropy is observed, as the compressive stress measured along the direction of incidence decreases at a greater rate than along the perpendicular direction. The implications of these results on the mechanisms proposed for amorphous diamond formation are discussed.