Diamond and related materials vol:2 issue:2-4 pages:272-277
Hydrogenated amorphous carbon films were deposited using an r.f. plasma-assisted chemical vapour deposition technique. Plasma parameters such as bias voltage and gas pressure were varied between 50 and 500 V and between 1.5 and 50 Pa respectively. Films were characterized according to their mechanical and physical properties such as internal stress (bending-beam measurements), hardness and Young's modulus (nanoindentation measurements), total hydrogen content and microstructure (IR absorption spectroscopy). Film thickness uniformity across various complex-shaped geometries (conductive and insulating balks; inside the cavity) was determined using step height profilometry after selectively etching away the amorphous carbon films through a mask in an oxygen plasma. The results are interpreted on the basis of fundamental plasma properties such as cathodic sheath, fringing-field and hollow cathode effects.