Optimized low leakage diodes, including photodiodes
AssigneeMicron Technology, Inc.
InventorsHoward E. Rhodes, Werner Juengling, Thomas A. Figura, Steven D. Cummings
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Abstract
A photodiode for use in an imager having an improved charge leakage. The photodiode has a doped region that is spaced away from the field isolation to minimize charge leakage. A second embodiment of invention provides a second implant to improve charge leakage to the substrate. The photodiodes according to the invention provide improve charge leakage, improved reactions to dark current and an improved signal to noise ratio. Also disclosed are processes for forming the photodiode.
Claims105
A diode, said diode comprising:
- an isolation region formed in a substrate;
- a first doped active layer of a first conductivity type formed in said substrate, wherein said doped layer is spaced apart from said isolation region;
- and
- a second doped active layer of a second conductivity type in contact with said first doped active layer, the contact of said first and second active layers forming a p-n junction.
A diode for use in an imaging device, said diode comprising:
- an isolation region formed in a substrate;
- a first doped active layer of a first conductivity type formed in said substrate of a second conductivity type, wherein said first doped active layer is spaced apart from said isolation region;
- and
- a second doped active layer of a first conductivity type formed within said first doped active layer, wherein said second doped active layer is doped to a higher dopant dose that said first doped active layer, wherein said first and second active layers and said substrate form a p-n junction.
An imager device comprising:
- (i) a processor;
- and
- (ii) an imaging device coupled to said processor, said imaging device comprising:
- a photodiode for use in an imaging device, said photodiode comprising:
- an isolation region formed in a substrate;
- a first doped photoactive layer of a first conductivity type formed in said substrate, wherein said doped layer is spaced apart from said isolation region;
- and
- a second doped photoactive layer of a second conductivity type in contact with said first doped photoactive layer, the contact of said first and second photoactive layers forming a p-n junction.
The imager according to claim 67, wherein said first doped photoactive layer is doped with phosphorous.
The imager according to claim 67, wherein said first doped photoactive layer is doped at a dopant dose of from about 1×1011 ions/cm2 to about 1×1016 ions/cm2.
An imager device comprising:
- (i) a processor;
- and
- (ii) an imaging device coupled to said processor, said imaging device comprising:
- a photodiode for use in an imaging device, said photodiode comprising:
- an isolation region formed in a substrate;
- a first doped photoactive layer of a first conductivity type formed in said substrate doped to a second conductivity type, wherein said first doped photoactive layer is spaced apart from said isolation region;
- and
- a second doped photoactive layer of a first conductivity type formed within said first doped photoactive layer, wherein said second doped photoactive layer is doped to a higher dopant dose that said first doped photoactive layer,
- wherein said first and second photoactive layers and said substrate form a p-n junction.
A method of forming a photodiode structure in a substrate, said method comprising the steps of:
- forming an isolation region in said substrate;
- forming a doped region of a first conductivity under said isolation region;
- forming a doped photoactive layer of a second conductivity in said substrate, wherein said doped photoactive layer is spaced apart from said isolation region.
A method of forming a photodiode in a substrate, said method comprising the steps of:
- forming an isolation region in said substrate;
- forming a doped region of a first conductivity under said isolation region;
- forming a first doped photoactive layer of a second conductivity in said substrate encompassed by said isolation region, wherein said first doped photoactive layer is spaced apart from said isolation region;
- and
- forming a second doped photoactive layer of a second conductivity within said first doped photoactive layer, wherein said second doped photoactive layer is doped at a dopant dose that is greater than said first doper photoactive layer.
Dependencies are inferred from the claim text.