Deposition of nanocrystalline thin TiO2 films for MOS capacitors using Sol–Gel spin method with Pt and Al top electrodes

Nanocrystalline titanium dioxide (TiO2) films were deposited by Sol–Gel spin coating method on well clean P〈1 0 0〉 Si substrate. Titanium isoproxide Ti(OC3H7O2)4 (TIP) was used as the Titania precursor. The thickness, composition, and surface morphology of the thin films were characterized using Stylus profilometer, X-ray diffraction (XRD), Field-Emission Scanning Electron Microscope (FESEM) and Atomic Force Microscope (AFM). The crystallite sizes of the TiO2 grains were measured from the typical diffraction peaks and were found to be approximately 23–54 nm. The XRD pattern and Raman spectrum analysis of the deposited film confirmed the polymorphism nature of TiO2 thin films. After annealing at high temperature; the phase transition, improvement in crystallinity, structure and property of the films were being observed. The six Raman peaks were analyzed at 145 cm−1, 199 cm−1, 397 cm−1, 516 cm−1 (doublet) and 637 cm−1 corresponding to active mode of anatase phase. Capacitance–Voltage (C–V) measurement analysis was performed to obtain various devices and process parameters. Metal Oxide Semiconductor (MOS) capacitors with Pt and Al as the top electrode were fabricated to explore electrical characteristics. The refractive index by ellipsometry was found 2.36 and dielectric constant was calculated as 58. In this study, the comparison of the leakage current for TiO2 thin films fabricated by various methods has also been reported.

► Nanocrystalline TiO2 films were deposited by Sol–Gel spin coating method.
► Refractive index 2.36 and dielectric constant 58 has been calculated.
► Temperature effects have been studied on phase, crystallinity and structure.
► Top electrode (Al and Pt) material affects C–V and I–V characteristics.