Method of making trench photosensor for a CMOS imager
First Claim
Patent Images
1. A method of forming a photosensor, comprising the steps of:
- providing a semiconductor substrate having a doped layer of a first conductivity type;
forming a trench in said doped layer;
doping the sides and bottom of said trench to form a doped region of a second conductivity type; and
forming an insulating layer on the sides and bottom of said trench over said doped region.
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Abstract
A trench photosensor for use in a CMOS imager having an improved charge capacity. The trench photosensor may be either a photogate or photodiode structure. The trench shape of the photosensor provides the photosensitive element with an increased surface area compared to a flat photosensor occupying a comparable area on a substrate. The trench photosensor also exhibits a higher charge capacity, improved dynamic range, and a better signal-to-noise ratio. Also disclosed are processes for forming the trench photosensor.
68 Citations
21 Claims
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1. A method of forming a photosensor, comprising the steps of:
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providing a semiconductor substrate having a doped layer of a first conductivity type;
forming a trench in said doped layer;
doping the sides and bottom of said trench to form a doped region of a second conductivity type; and
forming an insulating layer on the sides and bottom of said trench over said doped region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method of forming a photosensor, comprising the steps of:
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providing a semiconductor substrate having a doped layer of a first conductivity type;
forming a doped region of a second conductivity type in the doped layer;
forming a trench in said doped region so that the sides and bottom of said trench are of the second conductivity type; and
forming an insulating layer on the sides and bottom of said trench. - View Dependent Claims (17, 18, 19, 20, 21)
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Specification