Ti-doped Ta2O5 stacked capacitors

Ti-doped Ta₂O₅(~ 10; 30 nm) obtained by sputtering was studied with respect to their dielectric and electrical properties. The incorporation of Ti was performed by two original methods - surface doping where Ti layer was deposited on the top of Ta₂O₅ and bulk doping where the layer was embedded inside the Ta₂O₅. The surface doping is worthy for thin- and the bulk doping is more beneficial for thick-film stacks, (the current lowers with ~ 1-2 orders of magnitude). In the context of advanced high-k dielectrics (thinner layers) the surface doped Ta₂O₅ has better potential. The incorporation of Ti into Ta₂O₅ causes generation of negative oxide charge. The mechanism of current reduction is considered to be due to Ti-induced compensation of existing oxygen vacancies.