A contiguous deep trench includes a first trench portion having a constant width between a pair of first parallel sidewalls, second and third trench portions each having a greater width than the first trench portion and laterally connected to the first trench portion. A non-conformal deposition process is employed to form a conductive layer that has a tapered geometry within the contiguous deep trench portion such that the conductive layer is not present on bottom surfaces of the contiguous deep trench. A gap fill layer is formed to plug the space in the first trench portion. The conductive layer is patterned into two conductive plates each having a tapered vertical portion within the first trench portion. After removing remaining portions of the gap fill layer, a device is formed that has a small separation distance between the tapered vertical portions of the conductive plates.