Patent ID: 8084815

Claim:
A superjunction semiconductor device comprising: an edge p pillar having a rectangular ring shape with rounded corners; an active region surrounded by the edge p pillar, the active region having active p pillars arranged in an n region so as to form alternating active p and n pillars in the active region, the active p pillars having a stripe shape and extending in parallel along a vertical dimension with top and bottom ends separated from the edge p pillar; a termination region surrounding the edge p pillar; and one or more subsidiary p pillars each having a top end and a bottom end, the one or more subsidiary p pillars being disposed in the n region between a first active p pillar and a second active p pillar, a top end of the first active p pillar being lower, along the vertical dimension, than a top end of the second active p pillar, the one or more subsidiary p pillars being located between the top end of the first active p pillar and the top end of the second active p pillar such that the bottom end of each of the one or more subsidiary p pillars does not extend below the top end of the first p pillar, and the top end of each of the one or more subsidiary p pillars does not extend above the top end of the second p pillar, wherein a width of the bottom end of each of the one or more subsidiary p pillars is narrower than a width of the n pillars at the bottom end of the one or more subsidiary p pillars along a dimension perpendicular to the vertical dimension.