Abstract
Metal-insulator-metal (MIM) capacitors with single TiO 2 and a TiO 2 Y 2 O 3 stack as an insulator are explored in this letter. It is found that, at the process temperature higher than 400 °C, TiO 2 MIM capacitors demonstrate a high capacitance density at the price of an unacceptably high leakage current and voltage coefficient of capacitance (VCC). On the other hand, with the process temperature of 500 °C, TiO 2 Y 2 O 3 MIM capacitors display desirable characteristics in terms of a large capacitance density of 32.2 fFμm 2 , a low VCC of 3490 V 2 , small frequency dispersion, and a low leakage current of 4.5×10 -9 Acm 2 at 1 V. The Y 2 O 3 film not only provides a high dielectric-electrode band offset but also possesses high thermal stability against crystallization; both are important to suppress leakage current. In addition, the Y 2 O 3 film prevents a TiO 2 film from crystallization at 500 °C due to the increased entropy caused by incorporated Y atoms, and the amorphous TiO 2 film offers a high κ value to achieve a large capacitance density without sacrificing leakage current and VCC. © 2011 IEEE.