Semiconductor device
AssigneeRohm Co., Ltd.
InventorKenichi YOSHIMURA
Life of this patent
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Abstract
A semiconductor device includes a semiconductor layer having a principal surface, a first-conductivity-type well region formed at a surface layer portion of the principal surface of the semiconductor layer, a first-conductivity-type first impurity region that is formed at a surface layer portion of the well region and that has an inner wall portion, and a second-conductivity-type annular second impurity region formed at the surface layer portion of the well region on a more inward side than the inner wall portion such that a pn junction portion is formed between the well region and the second impurity region.
Claims14
A semiconductor device comprising:
- a semiconductor layer having a principal surface;
- a first-conductivity-type well region formed at a surface layer portion of the principal surface of the semiconductor layer;
- a first-conductivity-type first impurity region that is formed at a surface layer portion of the well region and that has an inner wall portion;
- and
- a second-conductivity-type annular second impurity region formed at the surface layer portion of the well region on a more inward side than the inner wall portion such that a pn junction portion is formed between the well region and the second impurity region.
Dependencies are inferred from the claim text.