CMOS imager and method of formation
AssigneeMicron Technology, Inc.
InventorHoward E. Rhodes
Life of this patent
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Abstract
One or more deep-array implants under the photosensitive region of a semiconductor substrate are conducted to improve optical cross-talk between pixel cells. According to an embodiment of the present invention, one or more deep-array implants of a first conductivity type are used to dope predefined regions of a well of a second conductivity type. This way, first conductivity type dopants from the one or more deep-array implants counterdope second conductivity type dopants from the predefined regions of the well. The dosage and energy of each deep-array implant may be optimized so that the collection of signal carriers by the photosensitive region and the photoresponse for different wavelengths are maximized.
Claims42
A color pixel cell for an imaging device, said color pixel cell comprising:
- a well of a first conductivity type formed in a substrate;
- a first, second and third doped regions formed in said well, said first, second and third doped regions each having different doping concentrations;
- a first, second and third photosensitive regions formed in said respective first, second and third doped regions for receiving first, second and third photocharges corresponding to a particular color wavelength;
- and
- a first, second and third floating diffusion regions of a second conductivity type formed in said respective first, second and third doped regions for receiving said respective photocharges transferred from said respective first, second and third photosensitive regions.
The color pixel cell of clam 19, wherein each of said photosensor is a photoconductor sensor.
A color pixel cell for an imaging device, said color pixel cell comprising:
- a well of a first conductivity type formed in a substrate;
- a first doped region for a red sensor cell having a first doping concentration;
- a second doped region for a blue sensor cell having a second doping concentration;
- a third doped region for a green sensor cell having a third doping concentration, wherein said first doping concentration is greater than said second doping concentration and third doping concentration, and said first doping concentration, said second doping concentration, and said third doping concentration each having different doping concentrations;
- a first, second and third photosensitive regions formed in said respective first doped region, second doped region, and third doped region for receiving first, second and third photocharges corresponding to a particular color wavelength;
- and
- a first, second and third floating diffusion regions of a second conductivity type formed in said respective first, second and third doped regions for receiving said respective photocharges transferred from said respective first, second and third photosensitive regions.
A color pixel cell for an imaging device, said color pixel cell comprising:
- a well of a first conductivity type formed in a substrate;
- a first doped region for a red sensor cell having a first doping concentration;
- a second doped region for a blue sensor cell having a second doping concentration;
- a third doped region for a green sensor cell having a third doping concentration, wherein said first doping concentration and said third doping concentration are greater than said second doping concentration, and said first doping concentration, said second doping concentration, and said third doping concentration each have different doping concentrations;
- a first, second and third photosensitive regions formed in said respective first doped region, second doped region, and third doped region for receiving first, second and third photocharges corresponding to a particular color wavelength;
- and
- a first, second and third floating diffusion regions of a second conductivity type formed in said respective first, second and third doped regions for receiving said respective photocharges transferred from said respective first, second and third photosensitive regions.
A color pixel cell for an imaging device, said color pixel cell comprising:
- a red pixel cell, a blue pixel cell and a green pixel cell, each comprising a respective first region having a first doping concentration, second region having a second doping concentration, and third region having a third doping concentration formed within a well of a first conductivity type formed in a substrate, wherein said first doping concentration, said second doping concentration, and said third doping concentration each have different doping concentrations;
- a photosensor formed in each one of said first region, second region, and third region for sensing respective red, blue and green color wavelengths;
- a reset transistor having a gate stack formed in association with each one of said first region, second region, and third region;
- a floating diffusion region of a second conductivity type formed in each one of said first region, second region, and third region, between said photosensor and said reset transistor for receiving charges from said photosensor, said reset transistor operating to periodically reset a charge level of said floating diffusion region;
- and
- an output transistor having a gate electrically connected to said floating diffusion region.
A CMOS imager comprising:
- a substrate having a first, second and third regions of a first conductivity type, said first, second and third regions each having a different doping concentration in said substrate from the other regions, and wherein each of said first, second and third regions has a respective photosensor formed therein for sensing respective red, blue and green color wavelengths;
- an array of pixel sensor cells formed in said first, second and third regions;
- and
- a circuit electrically connected to receive and process output signals from said array.
Dependencies are inferred from the claim text.