Image sensor and method for fabricating the same
DCFirst Claim
1. An image sensor, comprising:
- a semiconductor substrate;
an active area including a photodiode area formed in a predetermined position of the substrate, a floating diffusion area having a smaller area than the photodiode area and a channel area having a bottle-neck structure connecting to the photodiode area and the floating diffusion area;
a field area for isolating electrically the active area;
a field stop layer being formed beneath the field area and being wider than the field area in a direction towards the active area; and
a gate electrode formed on the substrate by covering the channel area and a portion of the photodiode contacted to the channel area.
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Abstract
The present invention provides an image sensor capable of suppressing the dark current due to crystalline defects occurring at an edge of a field oxide layer and a method for fabricating the same. The present invention provides an image sensor including: a semiconductor substrate; an active area including a photodiode area formed in a predetermined position of the substrate, a floating diffusion area having a smaller area than the photodiode area and a channel area having a bottle-neck structure connecting to the photodiode area and the floating diffusion area; a field area for isolating electrically the active area; a field stop layer being formed beneath the field area by having a wider area than the field area through an expansion towards the active area with a first width; and a gate electrode formed on the substrate by covering the channel area and having one side superposed with a second width on one entire side of the photodiode contacted to the channel area.
31 Citations
10 Claims
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1. An image sensor, comprising:
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a semiconductor substrate;
an active area including a photodiode area formed in a predetermined position of the substrate, a floating diffusion area having a smaller area than the photodiode area and a channel area having a bottle-neck structure connecting to the photodiode area and the floating diffusion area;
a field area for isolating electrically the active area;
a field stop layer being formed beneath the field area and being wider than the field area in a direction towards the active area; and
a gate electrode formed on the substrate by covering the channel area and a portion of the photodiode contacted to the channel area. - View Dependent Claims (2, 3)
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4. An image sensor, comprising:
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a substrate;
an active area including a photodiode area formed in a predetermined position of the substrate, a floating diffusion area having a smaller area than the photodiode area and a channel area having a bottle-neck structure connecting to the photodiode area and the floating diffusion area;
a field area for isolating electrically the active area;
a field stop layer being formed beneath the field area and being wider than the field area in a direction towards the active area; and
a gate electrode formed on the substrate by covering the channel area and a portion of the photodiode contacted to the channel area.
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5. A method for fabricating an image sensor, comprising the steps of:
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forming an isolation mask that exposes partially a surface of a substrate;
forming a first diffusion layer having a wider area than an area of the partially exposed substrate;
forming a field oxide layer having a smaller area than the first diffusion layer on the first diffusion layer;
forming a gate electrode on an active area of the substrate defined by the, field oxide layer;
forming a second diffusion layer being aligned to an edge of one side of the gate electrode in the substrate and to the first diffusion layer; and
forming a third diffusion layer being aligned with a predetermined distance from the edge of the one side of the gate electrode formed in the second diffusion layer. - View Dependent Claims (6, 7)
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8. A method for forming an image sensor, comprising the steps of:
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forming a first isolation mask that exposes a portion of a surface of one side of a substrate;
forming a first diffusion layer having a wider area than an exposed area of the substrate;
forming on the substrate a second isolation mask that exposes the other side of the substrate;
forming a second diffusion layer having an area identical to an exposed area of the substrate;
forming on the first diffusion layer a first field oxide layer having a smaller area than the first diffusion layer, and simultaneously forming on the second diffusion layer a second field oxide layer having an area identical to the second diffusion layer;
forming a gate electrode extending on the active area of the substrate and simultaneously on the second field oxide layer;
forming a third diffusion layer being aligned to an edge of one side of the gate electrode in the substrate and the first diffusion layer; and
forming a fourth diffusion layer being aligned with a predetermined distance from the edge of the one side of gate electrode in the third diffusion layer. - View Dependent Claims (9, 10)
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Specification