The invention is related to a memory device, including a substrate, a capacitor which is substantially C-shaped in a cross section parallel to the substrate surface and a word line coupling the capacitor. In an embodiment, the C-shaped capacitor is a deep trench capacitor, and in alternative embodiment, the C-shaped capacitor is a stack capacitor. Both inner edge and outer edge of the C-shaped capacitor can be used for providing capacitance.