COMPARISON OF THE DIELECTRIC PROPERTIES FOR DOPED AND UNDOPED TiO2 THIN FILMS

The dielectric properties of TiO2 thin films have been investigated on ITO/TiO2/Au structures for a large domain of signal frequencies (102Hz-106Hz). At 100Hz, the values of the electric capacitance increases from 5.22nF to 22nF, by doping with Nb (0.35 at. %) and to 10.2nF by doping with Ce (0.4 at. %). This increase is correlated with the increase of the dielectric constant of the film. At 100 Hz, the dielectric constant increase from 83.6 for the undoped sample, to 179 by doping with Ce and to 108, by doping with Fe. Nb impurities determine a large increase of the dielectric constant, till 371, which is very important in fabricating capacitors. The dependence of dielectric loss versus frequency was also examined