Superjunction device

摘要

A superjunction device in which corner portions of each annular-shaped second trench are composed of a plurality of alternately arranged first sides and second sides. The first sides are parallel to a plurality of parallel arranged first trenches in a current-flowing area, while the second sides are perpendicular to the first sides and the first trenches. Such design ensures that Miller indices of sidewalls and bottom face of any portion of each second trench belong to the same family of crystal planes. Moreover, with this design, the corner portions of the second trenches can be filled with a silicon epitaxial material at the same rate with the rest portions thereof, which ensures for the second trenches to be uniformly and completely filled without any defects in the corner portions and hence improve the performance of the superjunction device.

主权项

1. A superjunction device, comprising:
a semiconductor substrate having a first conductivity type; a semiconductor epitaxial layer having a first conductivity type, the semiconductor epitaxial layer being formed on the semiconductor substrate; a current-flowing area formed in the semiconductor epitaxial layer, the current-flowing area including a plurality of parallel arranged first trenches, each of the first trenches extending along a surface of the semiconductor substrate epitaxial layer in a first direction perpendicular to a direction of depth; a termination structure formed in the semiconductor epitaxial layer and enclosing the current-flowing area, the termination structure including a plurality of parallel arranged and substantially annular-shaped second trenches, each of the second trenches including a plurality of alternately arranged first sides and second sides, each of the first sides extending in the first direction, each of the second sides extending in a second direction both perpendicular to the first direction and the direction of depth; and a semiconductor epitaxial material having a second conductivity type, the semiconductor epitaxial material being filled in each of the first and second trenches, wherein the semiconductor epitaxial material filled in the first and second trenches form pillars having a second conductivity type, and portions of the semiconductor epitaxial layer between every two adjacent pillars having a second conductivity type form pillars having a first conductivity type, and wherein the pillars having a first conductivity type and the pillars having a second conductivity type are alternately arranged.