Patent ID: 8552496

Claim:
A high-voltage transistor comprising: a substrate having a top surface; a drain of a first conductivity type; a source of the first conductivity type; a first trench filled with a dielectric material that forms a first dielectric region, the first trench being elongated in a first lateral direction; a first conductive field plate member disposed in the first dielectric region, the first conductive field plate member being formed as an elongated finger having a length that extends in the first lateral direction and a width in a second lateral direction, the first lateral direction being orthogonal to the second lateral direction, the width being substantially smaller than the length, the first conductive field plate member terminating in a fingertip area at each of two opposite lateral ends of the elongated finger; a drift region of the first conductivity type that extends in a vertical direction from the drain toward the source, the dielectric material insulating the first conductive field plate member from the drift region, the drift region having a ring shape that extends in the first and second lateral directions that laterally surrounds the first trench, the ring shape being elongated in the first lateral direction; a second trench that laterally surrounds the drift region, the second trench being filled with the dielectric material that forms a second dielectric region; a second conductive field plate member disposed in the second dielectric region, an inner portion of the second dielectric region insulating the second conductive field plate member from the drift region, gate members disposed in the first and second dielectric regions between the drift region and the first and second conductive field plate members, respectively; and wherein the first conductive field plate member has a thickness that extends in the vertical direction from the top surface of the substrate downward, the first dielectric region laterally separating the drift region from the first conductive field plate member, a lateral width of the first dielectric region separating the first conductive field plate member from the drift region, the lateral width being substantially the same at all points along the thickness of the first conductive field plate member.