Method of forming an imaging device
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.
Claims22
A method of forming photosensors for an imaging device, said method comprising the steps of:
- forming a well of a first conductivity type in a substrate, said well having a first doping concentration;
- conducting at least one implant of a second conductivity type in at least a region of said well to form at least one doped region, said at least one doped region having a second doping concentration which is lower than said first doping concentration;
- and
- forming at least one photosensor for sensing charges of a particular color wavelength at an upper surface of said at least one doped region.
A method of forming a color pixel cell for an imaging device, said method comprising the steps of:
- forming a well of a first conductivity type in a substrate;
- forming at least three doped regions of said first conductivity type in said substrate, said at least three doped regions having different doping concentrations in said well;
- forming a photosensitive region in each of said at least three doped regions;
- forming a photosensor on an upper surface of said photosensitive region for receiving charges of a particular color wavelength;
- and
- forming a floating diffusion region of a second conductivity type in each one of said at least three doped regions for receiving charges transferred from said photosensitive region in the same well.
A method of forming a pixel array for an imaging device, said method comprising the steps of:
- forming multiple dopant regions in a well of a substrate, said well and said multiple dopant regions having a first conductivity type, said multiple dopant regions having different dopant concentrations;
- and
- forming a plurality of pixel sensor cells in said multiple dopant regions, wherein each pixel sensor cell has a photosensitive region, a photosensor formed on said photosensitive region for sensing charges of a particular color wavelength, and a floating diffusion region of a second conductivity type.
Dependencies are inferred from the claim text.