Image sensor pixel having photodiode with multi-dopant implantation
AssigneeOmniVision Technologies, Inc.
InventorHoward E. Rhodes
Life of this patent
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Abstract
An active pixel using a photodiode with multiple species of N type dopants is disclosed. The pixel comprises a photodiode formed in a semiconductor substrate. The photodiode is an N− region formed within a P-type region. The N− region is formed from an implant of arsenic and an implant of phosphorus. Further, the pixel includes a transfer transistor formed between the photodiode and a floating node and selectively operative to transfer a signal from the photodiode to the floating node. Finally, the pixel includes an amplification transistor controlled by the floating node.
Claims16
A method for forming a photodiode in a P-type semiconductor substrate, said photodiode being an N− region formed in said P-type semiconductor substrate, the method comprising:
- implanting a first N type dopant into said semiconductor substrate;
- and
- implanting a second N type dopant into said semiconductor substrate, wherein the combination of said first N type dopant and second N type dopant form said N− region in said semiconductor substrate and wherein said second N type dopant completely surrounds said first N type dopant.
A method for forming a photodiode in a N-type semiconductor substrate, said photodiode being an P− region formed in said N-type semiconductor substrate, the method comprising:
- implanting a first P type dopant into said semiconductor substrate;
- and
- implanting a second P type dopant into said semiconductor substrate, wherein the combination of said first P type dopant and second P type dopant form said P− region in said semiconductor substrate, wherein the first P type dopant is boron and the second P type dopant is indium and wherein said first P type dopant substantially surrounds said second P type dopant.
Dependencies are inferred from the claim text.