Image sensors with optical trench
First Claim
Patent Images
1. An image pixel comprising:
- a photo-conversion device formed over a substrate;
at least one optically transmissive layer formed over said substrate;
a trench formed within at least a portion of said substrate and defining an optical guide structure over the photo-conversion device; and
at least one material filling said trench, said material having a lower refractive index than a refractive index of said substrate such that said reflection is produced by a refractive index difference.
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Abstract
A device and method for providing an optical trench structure for a pixel which guides incoming light onto the photosensor of the pixel. The optical trench structure has an optically reflecting barrier that substantially mitigates optical crosstalk. The optical trench structure is made of low dielectric constant material with an index of refraction that is less than the index of refraction of the material of surrounding layers (e.g., the substrate). This difference in refractive index causes an internal reflection into an optical path existing between a lens and pixel.
99 Citations
37 Claims
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1. An image pixel comprising:
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a photo-conversion device formed over a substrate; at least one optically transmissive layer formed over said substrate; a trench formed within at least a portion of said substrate and defining an optical guide structure over the photo-conversion device; and at least one material filling said trench, said material having a lower refractive index than a refractive index of said substrate such that said reflection is produced by a refractive index difference. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An image sensor comprising:
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a plurality of pixels in an array, at least one of said pixels comprising; a photosensor; a lens for receiving incident light; at least one optically transmissive layer formed over said substrate; and a trench formed within at least a portion of said substrate and defining an optical guide structure over the photo-conversion device; and at least one material filling said trench, said material having a lower refractive index than a refractive index of said substrate such that said reflection is produced by a refractive index difference. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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21. A system comprising:
a processor coupled to an image sensor, said image sensor comprising; a photosensor; a lens for receiving incident light; at least one optically transmissive layer formed over said substrate; and an optical guide structure formed in said substrate, said optical guide structure comprising; a trench defining said optical guide structure, wherein said trench surrounds a lateral area defined by said photosensor; and at least one material filling said trench, said at least one material having a property of producing reflection of light within said optical guide structure. - View Dependent Claims (22, 23, 24, 25, 26)
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27. A method of forming an optical guide structure within a pixel of an imaging device, comprising the steps of:
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forming a photo-conversion device over a substrate; forming at least one optically transmissive layer over said substrate; etching a trench into at least a portion of said substrate, said trench surrounding a lateral area defined by said photo-conversion device; and filling said trench with at least one material suitable for producing an internal reflection of light within an area defined by said trench. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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Specification