A semiconductor device includes an isolated p-type well, wherein the isolated p-type well is a first electrode of a capacitor device; a capacitor dielectric on the isolated p-type well; a p-type polysilicon electrode over the capacitor dielectric, wherein the p-type polysilicon electrode is a second electrode of the capacitor device; a first p-type contact region in the isolated p-type well, laterally extending from a first sidewall of the p-type polysilicon electrode; a second p-type contact region in the isolated p-type well, laterally extending from a second sidewall of the p-type polysilicon electrode, opposite the first sidewall of the p-type polysilicon electrode, wherein a portion of the isolated p-type well between the first and second p-type contact regions is under the p-type polysilicon electrode and the capacitor dielectric; and an n-type isolation region surrounding the isolated p-type well. This device may be conveniently coupled to a fringe capacitor.