Patent ID: 8476530

Claim:
A device structure comprising: a substrate including an insulating layer; a contiguous trench including first, second, and third trench portions and located in said insulating layer, wherein said first trench portion has a pair of first parallel sidewalls, wherein a lateral distance between one of said pair of first parallel sidewalls and another of said pair of first parallel sidewalls is a first width, and said second and third trench portions are directly and laterally adjoined to said first trench portion; and a pair of conductive plates, each located on one side of said first trench portion, not contacting the other of said pair of conductive plates, and having a horizontal portion and a tapered vertical portion, wherein said horizontal portion is located directly on a horizontal surface of said insulating layer, and wherein a width of said tapered vertical portion decreases from said horizontal surface with distance toward a bottom surface of said contiguous trench, and wherein said second trench portion has a pair of second parallel sidewalls separated by a second width greater than said first width, and said third trench portion has a pair of third parallel sidewalls separated by a third width greater than said first width, and wherein said pair of conductive plates does not directly contact said second and third trench portions.