Patent ID: 8907421
Filing Date: 2014-12-09
Classification: H01L

Abstract:
1. A superjunction structure, comprising a first-type epitaxial layer and a plurality of second-type pillars formed therein, a part of the first-type epitaxial layer between each two adjacent second-type pillars serving as a first-type pillar, so as to form alternately arranged first-type pillars and second-type pillars, wherein: each second-type pillar consists of at least two sections in a vertical direction, a second section from the top down having a groove formed in its top, the groove having a profile wider at the top and narrower at the bottom, a first section from the top down being formed in the groove and also having a profile wider at the top and narrower at the bottom; each section of the second-type pillar includes a second type impurity, doping concentrations of the second type impurity in the respective sections decreasing from the top down; each first-type pillar includes first-type impurities distributed in the vertical direction, a doping concentration of the first-type impurities in a lower portion of the first-type pillar being greater than or equal to a doping concentration of the first-type impurities in an upper portion of the first-type pillar; in a bottom of the first-type epitaxial layer, a total quantity of the second-type impurity in the second-type pillars is less than a total quantity of the first-type impurities in the first-type pillars; in a top of the first-type epitaxial layer, a total quantity of the second-type impurity in the second-type pillars is greater than a total quantity of the first-type impurities in the first-type pillars, further wherein, the first-type is N-type and the second-type is P-type, or the first-type is P-type and the second-type is N-type.