Method of forming a photosensor comprising a plurality of trenches
AssigneeMicron Technology, Inc.
InventorHoward E. Rhodes
Life of this patent
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Abstract
A method of forming a multiple-trench photosensor for use in a CMOS imager having an improved charge capacity. The multi-trench photosensor may be either a photogate or photodiode structure. The multi-trench photosensor provides the photosensitive element with an increased surface area compared to a flat photosensor occupying a comparable area on a substrate. The multi-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 multi-trench photosensor.
Claims14
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 doped region of a second conductivity type in the doped layer;
- forming a plurality of trenches in said doped region so that the sides and bottom of each of said plurality of trenches are of the second conductivity type;
- and
- forming an insulating layer on the sides and bottom of each of said plurality of trenches of the photosensor.
A method of forming a photosensor comprising:
- forming a doped layer in a semiconductor substrate;
- forming a plurality of trenches in said doped layer to define a photosensistive area of the photosensor, wherein each of said plurality of trenches further comprises a plurality of sidewalls and a bottom;
- forming a doped region on the sidewalls and bottom of each of said plurality of trenches, wherein said doped region is opposite in conductivity type from said doped layer;
- and
- forming an insulating layer on the sidewalls and bottom of each of said plurality of trenches.
A method of forming a single photosensor comprising:
- providing a semiconductor substrate;
- forming a doped region in said semiconductor substrate;
- forming a photosensitive area comprising at least two trenches in said doped region, wherein each of said at least two trenches further comprises sidewalls and a bottom;
- forming a dielectric layer over said sidewalls and bottom of each of said at least two trenches of the single photosensor.
Dependencies are inferred from the claim text.