Solid-state image sensor
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsJun Hirai, Tooru Yamada
Life of this patent
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Abstract
A p+-type region 5 on a surface of a photodiode unit is formed over a region from a surface of the photodiode unit through a surface of a signal charge read-out unit 9 until reaching the charge transfer unit. Also, the following structure is adapted: the structure in which a boundary between the p+-type region 5 and the p++-type region 4 is not on a same plane with a boundary of an n-type impurity region which forms the photodiode unit on a side of the signal charge read-out unit. Further, a p+-type region 12 is formed between the p+-type region 5 and the p++-type region 4 on the surface of the photodiode unit. The p+-type region 12 has an impurity concentration between the impurity concentrations of the p+-type region 5 and the p++-type region 4.
Claims7
A solid-state image sensor comprising:
- photoelectric conversion units operable to photoelectrically convert incident light into signal charge, and to store the signal charge, said photoelectric conversion units being arranged two-dimensionally on a semiconductor substrate;
- a charge transfer unit operable to transfer the signal charge read from said photoelectric conversion unit;
- and
- a charge read-out unit operable to read out the signal charge stored in said photoelectric conversion unit to said charge transfer unit, said charge read-out unit being formed between said photoelectric conversion unit and said charge transfer unit,
- wherein each of said photoelectric conversion units includes:
- first conductive-type impurity regions formed on a surface of said semiconductor substrate;
- and
- a second conductive-type impurity region formed under the first conductive-type impurity regions, and
- a boundary of the second conductive-type impurity region on a side of said charge read-out unit is not on a same plane with any of boundaries of the first conductive-type impurity regions on the side of said charge read-out unit.
Dependencies are inferred from the claim text.