The morphology, chemical composition, microstructure and electrical properties of BC3 thin films subjected to melting by a nanosecond laser pulse were investigated. The original films were formed by pulsed laser co-deposition of B and C on a sapphire substrate at 150 and 350 °C. Morphological changes in the films depended on their initial structure. However, the structure “frozen” after irradiation in both films was attributed to the B-saturated graphite-like phase, the local composition of which varied due to the formation of inclusions of amorphous boron carbide. Before and after irradiation, the films showed a weakly decreasing dependence of the sheet resistance with increasing temperature from 4.2 to 330 K. After pulsed laser irradiation, the sheet resistance of the films decreased by ~ 2.6 times.

Structural features of CB_ x films obtained by pulsed laser ablation of targets made of pressed diamond powder with boron-powder additions at B/C atomic ratio of x = 0.33 have been studied. The films were deposited on heated substrates, so that diffusion processes involving C and B atoms on the surface and in the volume of films were possible. Selected conditions of film deposition ensured their effective doping with boron (0.4 ≤ x ≤ 0.6). The incorporation of B atoms was accompanied by the formation of B–C chemical bonds, whereas the formation of sp ^2 graphite bonds and their ordering in clusters with laminar packing was suppressed. The films possessed very low resistivity (~1.4 mΩ cm) at room temperature and exhibited metallic type of conductance on decreasing the temperature to 77 K.