The influence of imposing an electrical field parallel to the substrate of a growing metallic film was studied experimentally and analyzed theoretically. Ti films were deposited onto glass substrates using a filtered vacuum arc source while a voltageUof 0–300 V was applied between electrodes spaced 16 mm apart on the substrate surface. The current through the film was monitored during the deposition. Several characteristic stages of current evolution were observed after arc initiation: (1) an initial sharp jump of the current, (2) a stage of constant, relatively low current, (3) rapid current growth, (4) slower current growth, and (5) linear growth. Analyses showed that stages (1) and (2) are connected with current conduction through the plasma rather that through the sample while stages (3) and (4) are connected with tunneling and percolation during film formation. The tunneling stage could be distinguished only forU⩽6 V;in other cases, conduction through the plasma obscured the observation. The percolative exponent increased from 1.0 to 2.68 and the critical thickness decreased by a factor of 4.3 with an increasedUfrom 1 to 60 V. ©1997 American Institute of Physics.