Photoelectric conversion apparatus
AssigneeCanon Kabushiki Kaisha
InventorsHIROYUKI TSUCHIYA, HIROSHI SEKINE, KAZUHIRO MORIMOTO
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Abstract
A photoelectric conversion apparatus including an avalanche photodiode is provided. The photoelectric conversion apparatus includes an oxide film disposed on a semiconductor layer and a member provided on the oxide film. The member is disposed to overlap at least a boundary between a first semiconductor region and a third semiconductor region in plan view. The work function of the member differs from the work function of each of the first semiconductor region and the third semiconductor region so that a potential gradient for signal charge is generated in a depth direction of the semiconductor layer at at least the boundary.
Claims20
A photoelectric conversion apparatus including an avalanche photodiode, the apparatus comprising:
- a semiconductor layer having a first surface and a second surface;
- a first semiconductor region of a first conductivity type disposed at a first depth;
- a second semiconductor region of a second conductivity type disposed at a second depth that is greater than the first depth from the first surface, wherein the second semiconductor region forms the avalanche photodiode together with the first semiconductor region;
- a third semiconductor region of the first conductivity type provided in contact with an end portion of the first semiconductor region;
- an oxide film disposed on the first surface of the semiconductor layer;
- a member provided on an opposite side of the oxide film from the semiconductor layer in cross-sectional view;
- wiring;
- and
- a contact plug configured to connect the wiring to the first surface of the semiconductor layer,
- wherein the member is disposed to overlap at least a boundary between the first semiconductor region and the third semiconductor region in plan view,
- wherein the member is disposed between the wiring and the semiconductor layer, and
- wherein a work function of the member differs from a work function of each of the first semiconductor region and the third semiconductor region so that a potential gradient for signal charge is generated in a depth direction of the semiconductor layer at at least the boundary.
A photoelectric conversion apparatus having an avalanche photodiode, the apparatus comprising:
- a semiconductor layer having a first surface and a second surface;
- a first semiconductor region of a first conductivity type disposed at a first depth;
- a second semiconductor region of a second conductivity type disposed at a second depth that is greater than the first depth from the first surface, wherein the second semiconductor region forms the avalanche photodiode together with the first semiconductor region;
- a third semiconductor region of the first conductivity type provided in contact with an end portion of the first semiconductor region;
- an oxide film disposed on the first surface of the semiconductor layer;
- a protective film disposed on an opposite side of the oxide film from the semiconductor layer, wherein the protective film is made of a material that differs from a material used for the oxide film;
- an interlayer film disposed on an opposite side of the protective film from the oxide film;
- and
- a member provided between the oxide film and the protective film in cross-sectional view,
- wherein the member is disposed to overlap at least a boundary between the first semiconductor region and the third semiconductor region in plan view.
A photoelectric conversion apparatus including an avalanche photodiode, the apparatus comprising:
- a semiconductor layer having a first surface and a second surface;
- a first semiconductor region of a first conductivity type disposed at a first depth;
- A second semiconductor region of a second conductivity type disposed at a second depth that is greater than the first depth from the first surface, wherein the second semiconductor region forms the avalanche photodiode together with the first semiconductor region;
- a third semiconductor region of the first conductivity type provided in contact with an end portion of the first semiconductor region;
- an oxide film disposed on the first surface of the semiconductor layer;
- a member provided on an opposite side of the oxide film from the semiconductor layer in cross-sectional view;
- wiring;
- and
- a contact plug configured to connect the wiring to the first surface of the semiconductor layer,
- wherein the member is disposed to overlap at least a boundary between the first semiconductor region and the third semiconductor region in plan view,
- wherein the member is disposed between the wiring and the semiconductor layer, and
- wherein the member is made of second conductivity type polysilicon.
Dependencies are inferred from the claim text.