Optical-detection element, solid-state imaging device, and method for driving solid-state imaging device
AssigneesBrookman Technology, Inc., Ikegami Tsushinki Co., Ltd., Japan Atomic Energy Agency
InventorsTakashi Watanabe, Osamu Ozawa, Kunihiko Tsuchiya, Tomoaki Takeuchi
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Abstract
An optical-detection element includes a p-type supporting-layer, an n-type buried charge-generation region to implement a photodiode with the supporting-layer, a p-type shield region buried in the buried charge-generation region, a gate insulating-film contacted with the shield region, a transparent electrode on the gate insulating-film, a p-type well region buried in the supporting-layer, and an n+-type charge-readout region buried in the supporting-layer at an edge of the well region toward the buried charge-generation region.
Claims12
An optical-detection element comprising:
- a supporting-layer of a first conductivity type;
- a buried charge-generation region of a second conductivity type buried in an upper portion of the supporting-layer to implement a photodiode with the supporting-layer;
- a shield region of the first conductivity type having an impurity concentration higher than the supporting-layer and buried at an upper surface of the buried charge-generation region;
- a gate insulating-film contacted with an upper surface of the shield region;
- a transparent electrode provided on the gate insulating-film just above the buried charge-generation region, configured to implement a photogate structure, through which a light is incident on the buried charge-generation region;
- a well region of the first conductivity type having a higher impurity concentration than the supporting-layer and buried in the upper portion of the supporting-layer;
- and
- a charge-readout region of the second conductivity type having a higher impurity concentration than the buried charge-generation region and buried in the upper portion of the supporting-layer at an edge of the well region toward the buried charge-generation region,
- wherein the impurity concentration of the shield region is set to a value such that an electrostatic potential at a surface side of the shield region is changeable by a voltage applied to the transparent electrode, and a surface potential of the shield region is pinned by charges of the first conductivity type by the electrostatic potential induced in the shield region.
A solid-state imaging device in which a plurality of pixels is arranged, each of the plurality of pixels comprising:
- a supporting-layer of a first conductivity type;
- a buried charge-generation region of a second conductivity type buried in an upper portion of the supporting-layer to implement a photodiode with the supporting-layer;
- a shield region of the first conductivity type having an impurity concentration higher than the supporting-layer and buried at an upper surface of the buried charge-generation region;
- a gate insulating-film contacted with an upper surface of the shield region;
- a transparent electrode provided on the gate insulating-film just above the buried charge-generation region, configured to implement a photogate structure, through which a light is incident on the buried charge-generation region;
- a well region of the first conductivity type having a higher impurity concentration than the supporting-layer and buried in the upper portion of the supporting-layer;
- and
- a charge-readout region of the second conductivity type having a higher impurity concentration than the buried charge-generation region and buried in the upper portion of the supporting-layer at an edge of the well region toward the buried charge-generation region,
- wherein the impurity concentration of the shield region is set to a value such that an electrostatic potential at a surface side of the shield region is changeable by a voltage applied to the transparent electrode, and a surface potential of the shield region is pinned by charges of the first conductivity type by the electrostatic potential induced in the shield region.
Dependencies are inferred from the claim text.