Disclosed is a capacitor structure and method for forming the same. This structure has a conductive substrate, conductive fins extending above the substrate, and trenches extending into the substrate. These trenches are positioned between locations where the fins extend above the substrate. The invention includes an insulator in the trenches and covering the fins. This insulator separates the substrate and fins from a conductive top plate that covers the fins and fills the trenches. A bottom plate contact electrically connects the fins and the substrate such that the fins and the substrate comprise a bottom plate of the capacitor structure.