A storage capacitor structure of a planar display is disclosed. The storage capacitor includes a substrate, a bottom electrode, an insulator, and a top electrode. The bottom electrode or top electrode has an uneven surface toward the insulator interposed between the two electrodes in order to increase the capacitance of the storage capacitor structure. A method for fabricating such storage capacitor structure is also disclosed. It includes steps of providing a substrate; and forming a bottom electrode, an insulator, and a top electrode in sequence. The bottom electrode or the top electrode has the uneven surface by an etching step.