The present disclosure, in some embodiments, relates to a method of forming a capacitor structure. The method includes forming a capacitor dielectric layer over a lower electrode layer, and forming an upper electrode layer over the capacitor dielectric layer. The upper electrode layer is etched to define an upper electrode and to expose a part of the capacitor dielectric layer. A spacer structure is formed over horizontally extending surfaces of the upper electrode layer and the capacitor dielectric layer and also along sidewalls of the upper electrode. The spacer structure is etched to remove the spacer structure from over the horizontally extending surfaces of the upper electrode layer and the capacitor dielectric layer and to define a spacer. The capacitor dielectric layer and the lower electrode layer are etched according to the spacer to define a capacitor dielectric and a lower electrode.