Alternating current characterization of sputter deposited Ti oxide films

Ti oxide films with varying stoichiometries and different crystal structure s were prepared by reactive direct current magnetron sputtering in oxygen-d epleted plasmas. The complex dielectric permittivity epsilon was determined in the 10(-3)-10(7) Hz range from measurements using a capacitor configura tion. The real and imaginary parts of epsilon displayed power-law dependenc es from similar to 10 Hz up to a value between 1 and 10 kHz. Our data could be rationalized in terms of a model for screened hopping of vacancy-induce d charge carriers, but the details remain poorly understood.