Active pixel sensor array with simple floating gate pixels
First Claim
1. An imaging device comprising:
- a monolithic semiconductor integrated circuit substrate;
a focal plane array of pixel cells, each one of said pixel cells comprising;
a photogate electrode, overlying a photogate portion of said substrate, and capable of accumulating photo-generated charge in an underlying portion of said substrate, anda charge coupled device section formed on said substrate adjacent said photogate portion, having an output transistor whose gate is connected to said photogate electrode to form a floating gate to produce an electrical signal indicative of said photo-generated charge and at least one charge coupled device stage capable of transferring charge from said underlying portion of the substrate to a drain of said output transistor during a reset operation.
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Accused Products
Abstract
An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node. There is also a readout circuit, part of which can be disposed at the bottom of each column of cells and be common to all the cells in the column. A Simple Floating Gate (SFG) pixel structure could also be employed in the imager to provide a non-destructive readout and smaller pixel sizes.
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Citations
30 Claims
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1. An imaging device comprising:
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a monolithic semiconductor integrated circuit substrate; a focal plane array of pixel cells, each one of said pixel cells comprising; a photogate electrode, overlying a photogate portion of said substrate, and capable of accumulating photo-generated charge in an underlying portion of said substrate, and a charge coupled device section formed on said substrate adjacent said photogate portion, having an output transistor whose gate is connected to said photogate electrode to form a floating gate to produce an electrical signal indicative of said photo-generated charge and at least one charge coupled device stage capable of transferring charge from said underlying portion of the substrate to a drain of said output transistor during a reset operation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. An imaging device comprising:
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a monolithic semiconductor integrated circuit substrate; a focal plane array of pixel cells formed on said substrate by an integrated circuit process that is compatible with a complementary metal oxide semiconductor (CMOS) process, each one of said pixel cells comprising, a photogate electrode overlying said substrate and operable to accumulate photo-generated charge in an underlying photogate portion of said substrate, a barrier gate formed on said substrate adjacent said photogate portion, and a pixel transistor formed on said substrate and configured to have a first diffusion region adjacent said barrier gate, a gate and a second diffusion region, said gate connected to said photogate electrode to form a floating gate, wherein said barrier gate is operable to transfer said photo-generated charge from said underlying photogate portion of said substrate to said first diffusion region of said pixel transistor, and wherein said gate of said pixel transistor produces an electrical signal comprising a signal component indicative of said photo-generated charge and a noise component indicative of noise associated with said pixel; and MOS image signal processing electronics integrated on said substrate and connected to communicate with said focal plane array and to provide on-chip signal processing of electrical signals from said pixel cells. - View Dependent Claims (22, 23)
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24. An imaging device comprising:
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a monolithic semiconductor integrated circuit substrate; a focal plane array of pixel cells formed on said substrate by an integrated circuit process that is compatible with complementary metal oxide semiconductor (CMOS) process, each one of said pixel cells comprising, a photogate overlying said substrate and operable to accumulate photo-generated charge in an underlying portion of said substrate, a barrier gate formed on said substrate adjacent said photogate, and a pixel transistor formed on said substrate and configured to have a drain adjacent said barrier gate, a gate and a source, a capacitor having a terminal connected to both said photogate and said gate of said pixel transistor to make said gate of said pixel transistor a floating gate, wherein said barrier gate is operable to transfer said photo-generated charge from said underlying portion of said substrate under said photogate to said drain of said pixel transistor which produces an electrical signal having a signal component indicative of said photo-generated charge. - View Dependent Claims (25, 26)
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27. A method, comprising:
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producing charge in a portion of a semiconductor substrate under a photogate electrode in response to incident photons incident to said portion; using a transfer gate formed in said substrate next to said photogate to output said charge in said portion; using a drain of an output transistor formed in said substrate next to said transfer gate to receive said charge from said portion; and connecting a gate of said output transistor to said photogate to form a floating gate so as to convert said charge into an electrical signal. - View Dependent Claims (28, 29, 30)
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Specification