US Patent 7745280 Metal-insulator-metal capacitor structure

A metal-insulator-metal capacitor structure includes a lower electrode, a buffer layer, a barrier layer, a dielectric layer and an upper electrode. The lower electrode is disposed in the buffer layer. The barrier layer covers part of the lower electrode and is disposed between the lower electrode and the upper electrode. The buffer layer serves as an etching stop layer to define the dielectric layer. The dielectric layer in the metal-insulator-metal capacitor structure has a uniform and ideal thickness.