Dielectric and transport properties of magnetron sputtered titanium dioxide thin films

Titanium dioxide (TiO2) thin films were prepared by DC magnetron sputtering onto well-cleaned p-type silicon substrates. The thickness, composition and surface morphology of the films were analyzed using alpha step profilometer, Auger electron spectroscopy (AES) and atomic force microscope (AFM) respectively. The X-ray diffraction (XRD) studies reveal the amorphous nature of the deposited film. Thin film capacitors of the type Al/TiO2/Si/Al have been fabricated. Dielectric and AC conduction studies were performed at various frequencies (10 kHz to 10 MHz) and temperatures (300-390 K). Dielectric constant value of TiO2 film of thickness 140 nm was evaluated at room temperature and at a frequency of 1 MHz as 5.5. The mechanisms responsible for the AC and DC conduction in these films have been identified. For the first time, the trap density, mobility values of TiO2 thin films are evaluated from the space charge limited current (SCLC) measurements as 1.637×1017 cm−3, 2×10−11 cm2 V−1 s−1, respectively. The AC and DC activation energies have been calculated as 0.097 and 0.136 eV, respectively.