Semiconductor device
AssigneeRohm Co., Ltd.
InventorShinya UMEKI
Life of this patent
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Abstract
A semiconductor device includes a first conductive type semiconductor layer which has a principal surface, a second conductive type well region which demarcates an active region and an outer region on the principal surface and is formed on a surface layer portion of the principal surface and includes a high concentration portion high in impurity concentration on the active region side and includes a low concentration portion lower in impurity concentration than the high concentration portion on the outer region side, and a second conductive type impurity region of the active region which is formed on a surface layer portion of the principal surface.
Claims19
A semiconductor device comprising:
- a first conductive type semiconductor layer which has a principal surface;
- a second conductive type well region which demarcates an active region in an internal portion of the semiconductor layer and demarcates an outer region on the principal surface in a peripheral edge portion of the semiconductor layer in plan view and is also formed in an annular shape which surrounds the internal portion of the semiconductor layer in a surface layer portion of the principal surface and includes a first concentration portion high in impurity concentration on the active region side and includes a second concentration portion lower in impurity concentration than the first concentration portion on the outer region side;
- a second conductive type impurity region of the active region which is formed on a surface layer portion of the principal surface;
- and
- a principal surface electrode connected to the well region, wherein
- the first concentration portion is formed in an annular shape which surrounds the internal portion of the semiconductor layer in plan view and has a first bottom portion including a first flat portion in sectional view,
- the second concentration portion is formed in an annular shape which surrounds the first concentration portion in plan view and has a second bottom portion including a second flat portion in sectional view, and
- the second concentration portion has a second thickness less than a first thickness of the first concentration portion.
Dependencies are inferred from the claim text.