CMOS imager with storage capacitor
AssigneeMicron Technology, Inc.
InventorHoward E. Rhodes
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Abstract
A CMOS imager having an improved signal to noise ratio and improved dynamic range is disclosed. The CMOS imager provides improved charge storage by fabricating a storage capacitor in parallel with the photocollection area of the imager. The storage capacitor may be a flat plate capacitor formed over the pixel, a stacked capacitor or a trench imager formed in the photosensor. The CMOS imager thus exhibits a better signal-to-noise ratio and improved dynamic range. Also disclosed are processes for forming the CMOS imager.
Claims169
A photosensor for use in a CMOS imaging device, said photosensor comprising:
- a doped layer of a first conductivity type formed in a substrate;
- a charge collection region formed in said doped layer;
- and
- a storage capacitor connected to said charge collection region to store charge accumulated by said charge collection region.
A photosensor for use in an imaging device formed in a single integrated circuit, said photosensor comprising:
- a doped layer of a first conductivity type formed in a substrate;
- a charge collection region formed in said doped layer;
- a first doped region of a second conductivity type formed in said doped layer adjacent said charge collection region;
- a storage capacitor;
- and
- a contact connecting said first doped region to said storage capacitor.
A photosensor for use in an imaging device, said photosensor comprising:
- a doped layer of a first conductivity type formed in a substrate;
- a charge collection region formed in said doped layer;
- a first doped region of a second conductivity type formed in said doped layer adjacent said charge collection region;
- and
- a trench storage capacitor formed in said substrate adjacent said first doped region and connected to said first doped region to store charge collected in said charge collection region.
A CMOS imager system comprising:
- (i) a processor;
- and
- (ii) a CMOS imaging device coupled to said processor, said CMOS imaging system comprising:
- a doped layer of a first conductivity type formed in a substrate;
- a charge collection region formed in said doped layer;
- a first doped region of a second conductivity type formed in said doped layer adjacent said charge collection region;
- a storage capacitor;
- and
- a contact connecting said first doped region to said storage capacitor.
A CMOS imager system comprising:
- (i) a processor;
- and
- (ii) a CMOS imaging device coupled to said processor, said CMOS imaging system comprising:
- a doped layer of a first conductivity type formed in a substrate;
- a charge collection region formed in said doped layer;
- a first doped region of a second conductivity type formed in said doped layer adjacent said charge collection region;
- and
- a trench storage capacitor formed in said substrate adjacent said first doped region and connected to said first doped region to store charge collected in said charge collection region.
A method of forming a CMOS imager having improved charge storage comprising the steps of:
- providing a semiconductor substrate having a doped layer of a first conductivity type;
- forming a first doped region of a second conductivity type in the doped layer;
- forming a storage capacitor over said substrate;
- and
- forming a contact between said first doped region and a charge storage capacitor.
A method of forming a CMOS imager having improved charge storage comprising the steps of:
- providing a semiconductor substrate having a doped layer of a first conductivity type;
- forming a first doped region of a second conductivity type in the doped layer;
- forming a trench in said doped layer adjacent said first doped layer;
- forming a first conductive layer in said trench;
- forming an insulating layer over said first conductive layer in said trench;
- and
- forming a second conductive layer over said insulating layer to form a trench capacitor.
Dependencies are inferred from the claim text.