Abstract: A metal-insulator-metal (MIM) capacitor having a top electrode, a bottom electrode and a capacitor dielectric layer is provided. The top electrode is located over the bottom electrode and the capacitor dielectric layer is disposed between the top and the bottom electrode. The capacitor dielectric layer comprises several titanium oxide (TiO2) layers and at least one tetragonal structure material layer. The tetragonal structure material layer is disposed between two titanium oxide layers and each tetragonal structure material layer has the same or a different thickness. Leakage path can be cut off through the tetragonal material layer between the titanium oxide layers. In the meantime, the tetragonal structure material layer can induce the titanium oxide layers to transform into a high k rutile phase.

Abstract: An oxalate route coprecipitation process for preparing a superconducting YBaCuO system precursor powder comprises preparing an aqueous solution of nitrates of yttrium, barium and copper, which is then mixed with an organic solution containing a dibasic oxalate ester, an organic base and acetone. An ultrasound vibration is applied to the mixture to coprecipitate oxalates of yttrium, barium and copper. The decomposition of the oxalate ester is enhanced to an optimum rate as the result of the homogeneous phase contributed by acetone which is miscible with both water and the oxalate ester. The ultrasound vibration segregates the precipitate particles thereby preventing the coagulation of the particles and assuring fine and uniform particle size.