This work investigated the effect of ion bombardment on tantalum thin films deposited by radio frequency magnetron sputtering at ambient temperature on (100) oriented silicon and polycrystalline aluminum. Negative bias voltage, 0 to -300 V, was applied to the substrate to control the energy of the ions bombarding the growing film. The films were characterized by X-ray diffraction, Rutherford backscattering, scanning electron microscopy, and atomic force microscopy. The desired pure body centered cubic phase Ta films were deposited with -150 V substrate bias and with comparable atom and ion fluxes, conditions significantly different than reported earlier, and achievable in a relatively simple system that is easy to scale to industrial operation. (C) 2007 Elsevier B.V. All rights reserved.