Deposition of highly adhesive amorphous carbon films with the use of preliminary plasma-immersion ion implantation

The usability of the following two types of plasma generators for deposition of highly adhesive a-C:H films on the large area substrates has been studied: (1) a source of plasma generated by means of a non-self-sustained arc discharge in low-pressure gas; and (2) an ion-plasma source on the basis of a Hall current accelerator with closed electron drift. The distinctive features of both sources are: (a) the possibility of the generation of extended flows (up to 2 m) of relatively dense plasma (∼1010 cm−3); and (b) control of the plasma ionization degree, allowing realization of both preliminary plasma-immersion ion implantation (PIII) of a substrate and subsequent plasma-immersion ion-assisted deposition (PIID) of a-C:H film. The results of experimental investigations into the characteristics of the sources in different operational regimes are presented. Taking into account the probe measurements of plasma parameters, both generators have been optimized to operate in the PIII and PIID regimes. Characteristics of the pulsed negative bias applied to the substrate in both regimes have also been determined. It was shown that both sources allowed deposition of a diamond-like film on large-area substrates with a growth rate of 100–300 nm h−1. A hard (20–30 GPa) a-C:H coating containing approximately 60% of carbon atoms with sp3 hybridization and having satisfactory adhesion to the substrate can be obtained if short (∼60 μs) high-voltage (∼6 kV) bias pulses are applied to the substrate.