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EP0854516A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Partially pinned photodiode for solid state image sensors

Assignee: Omnivision Technologies Inc
•
Filing: 1998-01-08
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Granted: —
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Expires: 2018-01-08
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Abstract

Abstract A pixelated image sensor having comprising a partially pinned photodiode which is formed a semiconductor of a first conductivity type formed on a surface of the sensor with at least one photodiode formed, within the semiconductor near the surface, the photodiode being formed from a second conductivity type opposite the first conductivity type; a pinning layer formed on the surface over at least a portion of the photodiode creating a pinned photodiode region, the pinning layer being formed from the first conductivity type; and an unpinned region formed near the surface in an area outside the portion used to form the pinning layer, the unpinned region is formed as a floating region that is employed as a capacitor. The partially pinned photodiode is useful in expanding the fill factor of photodetectors employing photodiode technology.

Inventors

  • 👤 Teh-Hsuang c/o Eastman Kodak Company Lee
  • 👤 Robert Michael c/o Eastman Kodak Company Guidash
  • 👤 Paul Poo-Kam c/o Eastman Kodak Company Lee

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-09 12:41
CPC Classifications
H; H10; H10F; H10F39/00; H10F39/011; H10F39/014; H10F39/10; H10F39/12; H10F39/18; H10F39/186; H10F39/80; H10F39/803; H10F39/802; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y02E10/547

Claims Analysis

Total Claims: 10
Claim 1
Independent Claim 121 words
An image sensor having at least one pixel comprising: a semiconductor of a first conductivity type within the sensor, the semiconductor being formed on a surface of the sensor; at least one photodiode formed, within the semiconductor near the surface, the photodiode being formed from a second conductivity type opposite the first conductivity type; a pinning layer formed on the surface over at least a portion of the photodiode creating a pinned photodiode region, the pinning layer being formed from the first conductivity type; an unpinned region formed within the photodiode near the surface in an area outside the portion used to form the pinning layer; and a sensing node coupled to the unpinned region interfacing the photodiode to external circuitry.
Claim 2
Dependent Claim 16 words
The image sensor of claim 1 further comprising a control circuit operatively coupled to the pixel.
Claim 3
Dependent Claim 21 words
The image sensor of claim 1 further comprising reset means for removing charge from the photodiode portion to a drain area.
Claim 4
Dependent Claim 23 words
The image sensor of claim 1 wherein the unpinned region is formed having a layer of the second conductivity type at the surface.
Claim 5
Dependent Claim 34 words
The image sensor of claim 1 wherein the sensor is an active pixel sensor and the unpinned region is a floating region that functions as a capacitor that is operatively coupled to a transistor.
Claim 6
Dependent Claim 16 words
The image sensor of claim 5 wherein the transistor is operatively coupled to CMOS control circuitry.
Claim 7
Dependent Claim 31 words
The image sensor of claim 1 wherein the pinned photodiode region further comprises a gradient dopant level formed to create an electrostatic gradient capable of pushing electrons towards the unpinned region.
Claim 8
Dependent Claim 19 words
The image sensor of claim 1 further comprising utilization means for facilitating dynamic range compression operation of the sensor.
Claim 9
Dependent Claim 19 words
The image sensor of claim 1 wherein the control circuitry is selected from one of either CMOS, PMOS, NMOS.
Claim 10
Independent Claim 127 words
A method of making an image sensor comprising the steps of: firstly providing a semiconductor having a first conductivity type within the sensor, such that the semiconductor is formed on a surface of the sensor; secondly providing at least one photodiode within the semiconductor near the surface from a second conductivity type opposite the first conductivity type; thirdly providing a pinning layer from the first conductivity type formed on the surface over at least a portion of the photodiode creating a pinned photodiode region; fourthly providing an unpinned region within the photodiode outside the portion on the surface used to form the pinning layer such that the unpinned region is formed near the surface and is coupled to a sensing node interfacing the photodiode to external circuitry

References Cited (Backward Citations)

US5262871A Cited
EP0738010A2 Cited

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