A method for fabricating a metal-insulator-metal (MIM) capacitor is provided. The MIM capacitor includes a substrate, a first metal layer, a deposition structure, a dielectric layer and a second metal layer. The first metal layer is disposed on the substate and has a planarized surface. The deposition structure is disposed on the first metal layer, and at least a portion of the deposition structure extends into the planarized surface, wherein the first metal layer and the deposition structure have the same material. The dielectric layer is disposed on the deposition structure. The second metal layer is disposed on the dielectric layer.