Electrical characteristics of Ti-doped Ta 2O 5 stacked capacitors

Abstract

Ti-doped Ta 2O 5 (∼ 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 Ta 2O 5 and bulk doping where the layer was embedded inside the Ta 2O 5. 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 Ta 2O 5 has better potential. The incorporation of Ti into Ta 2O 5 causes generation of negative oxide charge. The mechanism of current reduction is considered to be due to Ti-induced compensation of existing oxygen vacancies.