Thin films of zirconia have been deposited by an inductively coupled plasma assisted chemical vapor deposition reactor from a tetra (tert-butoxy)-zircon precursor diluted in Ar and O-2 gas mixture. An independent rf generator is used to carefully control the substrate negative bias voltage during the deposition. Zirconia thin films, with thickness up to 10 mu m were deposited on Si(100) polished wafers under different plasma conditions. Correlation between deposition parameters and microstructure has been established showing that the ion bombardment has a large influence on the coating characteristics. In particular, the possibility of tailoring mechanical properties of the films by controlling the applied de bias voltage is discussed.