High capacitance density metal-insulator-metal structure based on Al2O3-HfTiO nanolaminate stacks

The authors describe metal-insulator-metal (MIM) capacitors comprising a five layer Al2O3-HfTiO nanolaminate stack with a total thickness of similar to 29 nm. At room temperature they demonstrate a capacitance density of similar to 14 fF/mu m(2), a leakage current density of similar to 1x10(-6) A/cm(2) at 1 V, a temperature capacitance coefficient of 380 ppm/degrees C as well as corresponding linear and quadratic voltage coefficients of 350 ppm/V and 570 ppm/V-2, respectively. They compare the structure to a MIM capacitor having a uniform HfTiO insulator film. That device exhibits a larger capacitance density (similar to 28 fF/mu m(2)) but its electrical properties are found to be poorer than those of the structures utilizing the nanolaminate stack.