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Hydrogen-free carbon thin films prepared by unbalanced magnetron sputtering

Hydrogen-free carbon films were deposited and synthesized by unbalanced magnetron sputtering (UBMS) using a graphite target in Ar atmosphere. The ion beam flow density was measured by a Langmuir probe under the condition of deposition DLC films. The results indicated that this unbalanced magnetron sputtering system can obtain ion beam density as high as 2.0 mAcm-2 even at low pressure of 0.5 Pa with an excitation current of 120 A, far larger than 0.3 mAcm-2 in a conventional balanced magnetron sputtering (MS) system. Hydrogen-free carbon films were deposited by PVD method with a rectangle graphite target of 480×120 mm. The Raman spectrum of carbon film was presented. It was proved that the film's structure is a typical diamond-like carbon. The Raman intensity of diamond and graphite peak ID/IGis as high as 2.26. Surface morphology was investigated by using an Atomic Force Microscope (AFM). The image indicated that the surface of carbon films is smooth; with the grains size about 10 nm and the surface roughness Rα about 2.5 nm, respectively. IR spectrum presented high optical transparency of 61.4% coated on single side of Ge sample, and no obvious absorption peaks were founded between 5000 and 1000 cm-1 owe to lack of hydrogen.