The present disclosure provides a method of forming a capacitor structure and a capacitor structure. A semiconductor-on-insulator substrate is provided comprising a semiconductor layer, a buried insulating material layer and a semiconductor substrate material. A shallow trench isolation structure defining a first active region on the SOI substrate is formed, the first active region having a plurality of trenches formed therein. Within each trench, the semiconductor substrate material is exposed on inner sidewalls and a bottom face. A layer of insulating material covering the exposed semiconductor substrate material is formed, and an electrode material is deposited on the layer of insulating material in the first active region.