CMOS imager with a self-aligned buried contact
First Claim
1. An imaging device comprising:
- a substrate;
a photosensitive area within said substrate for accumulating photo-generated charge in said photosensitive area;
a floating diffusion region in said substrate for receiving photo-generated charge from said photosensitive area;
a readout circuit comprising at least an output transistor formed in said substrate; and
, a buried contact for interconnecting said floating diffusion region with said output transistor.
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Accused Products
Abstract
An imaging device formed as a CMOS semiconductor integrated circuit includes a buried contact line between the floating diffusion region and the gate of a source follower output transistor. The self-aligned buried contact in the CMOS imager decreases leakage from the diffusion region into the substrate which may occur with other techniques for interconnecting the diffusion region with the source follower transistor gate. Additionally, the self-aligned buried contact is optimally formed between the floating diffusion region and the source follower transistor gate which allows the source follower transistor to be placed closer to the floating diffusion region, thereby allowing a greater photo detection region in the same sized imager circuit.
40 Citations
102 Claims
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1. An imaging device comprising:
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a substrate;
a photosensitive area within said substrate for accumulating photo-generated charge in said photosensitive area;
a floating diffusion region in said substrate for receiving photo-generated charge from said photosensitive area;
a readout circuit comprising at least an output transistor formed in said substrate; and
,a buried contact for interconnecting said floating diffusion region with said output transistor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. An imaging device comprising
a semiconductor integrated circuit substrate; -
a photosensitive device formed on said substrate for accumulating photo-generated charge in an underlying region of said substrate;
a floating diffusion region in said substrate for receiving said photo-generated charge;
a readout circuit comprising at least an output transistor formed in said substrate; and
said floating diffusion region being connected to said output by a buried contact via interconnectors. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43)
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44. A processing system comprising:
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(i) a processor; and
(ii) a CMOS imaging device coupled to said processor and including;
a substrate;
a photosensitive area within said substrate for accumulating photo-generated charge in said photosensitive area;
a floating diffusion region in said substrate for receiving photo-generated charge from said photosensitive area;
a readout circuit comprising at least an output transistor formed in said substrate; and
,a buried contact for interconnecting said floating diffusion region with said output transistor. - View Dependent Claims (45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62)
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63. An imaging device comprising:
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a substrate;
a photosensitive area within said substrate for accumulating photo-generated charge in said photosensitive area;
a readout circuit comprising at least an output transistor formed in said substrate; and
,a buried contact formed over a doped region in said substrate and between two structures on said substrate for electrically connecting said imaging device, wherein said structures are selected from a transistor gate and an isolation region. - View Dependent Claims (64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83)
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84. A processing system comprising:
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(i) a processor; and
(ii) a CMOS imaging device coupled to said processor and including;
a substrate;
a photosensitive area within said substrate for accumulating photo-generated charge in said photosensitive area;
a readout circuit comprising at least an output transistor formed on said substrate; and
,a buried contact formed over a doped region in said substrate and between two structures on said substrate electrically connecting said imaging device, wherein said structures are selected from a transistor gate and an isolation region. - View Dependent Claims (85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102)
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Specification