Dielectric and transport properties of magnetron sputtered titanium dioxide thin films

Abstract

Titanium dioxide (TiO 2) 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/TiO 2/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 TiO 2 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 TiO 2 thin films are evaluated from the space charge limited current (SCLC) measurements as 1.637×10 17 cm −3, 2×10 −11 cm 2 V −1 s −1, respectively. The AC and DC activation energies have been calculated as 0.097 and 0.136 eV, respectively.