Capacitance-voltage analysis of a high-k dielectric on silicon

Device characteristics of TiO2 gate dielectrics deposited by a sol-gel method and DC sputtering method on a P-type silicon wafer are reported. Metal-oxide-semiconductor capacitors with Al as the top electrode were fabricated to study the electrical properties of TiO2 films. The films were physically characterized by using X-ray diffraction, a capacitor voltage measurement, scanning electron microscopy, and by spectroscopy ellipsometry. The XRD and DST-TG indicate the presence of an anatase TiO2 phase in the film. Films deposited at higher temperatures showed better crystallinity. The dielectric constant calculated using the capacitance voltage measurement was found to be 18 and 73 for sputtering and sol-gel samples respectively. The refractive indices of the films were found to be 2.16 for sputtering and 2.42 for sol-gel samples.