Anodic TiO2 films doped with alkali-earth oxides

TiO2 is reported to have a dielectric constant ranging from 60-160. It is therefore an attractive dielectric material in an electrolytic capacitor. The present research deals with understanding the behavior of the dielectric and with further enhancing its dielectric properties. Phosphoric acid has been used as the electrolyte and a dielectric constant of about 150 has been obtained. Titanium is known to form titanates with alkali earth elements, which possess extremely high dielectric constants. The paper presents experimental work on doping of Ti to enhance the dielectric constant of TiO2 by incorporating alkali-earth titanate molecules into the dielectric. SEM, AFM, TEM were used to study the morphology and the defects in the dielectric film and XPS was used to study concentration profiles of dopants over the thickness of the dielectric film.