CMOS active pixel with scavenging diode

• US 6,365,926 B1
• Filed: 09/20/2000
• Issued: 04/02/2002
• Est. Priority Date: 09/20/2000
• Status: Expired due to Term

• Current Assignee: Omnivision Technologies Incorporated (Will Semiconductor Co., Ltd. Shanghai)
• Original Assignee: Eastman Kodak Company
• Inventors: Guidash, Robert M.
• Primary Examiner(s): NGO, NGAN V
• Application Number:
  US09/666,619
• Time in Patent Office: 559 Days
• Field of Search: 257/232, 257/233, 257/291, 257/292, 257/369
• US Class Current: 257/292
• CPC Class Codes: H01L 27/14609 Pixel-elements with integrated switching, control, storage or amplification elements scanning details of imagers (circuitry of solid-state image sensors H04N25/00); circuitry of imagers H04N25/70
• CPC Class Codes: H01L 27/14632 Wafer-level processed structures
• CPC Class Codes: H01L 27/14656 Overflow drain structures

Abstract

A method and structure of a camera includes an array of pixels making up a complementary metal oxide semiconductor active pixel image sensor. At least one of the pixels includes a photodetector, a voltage source for supplying voltage to the photodetector, and a scavenging diode adjacent the photodetector that can be connected to the voltage source. The scavenging diode is positioned between adjacent ones of the pixels and prevents electrons outside the photodetector from migrating to the photodetector.

Claims

1. A complementary metal oxide semiconductor (CMOS) active pixel image sensor, comprising an array of pixels, at least one of said pixels comprising:

a photodetector;

active circuit components adapted to read signals from said photodetector;

a voltage source supplying voltage to said circuit components; and

a scavenging diode connected to said voltage source,

wherein said scavenging diode prevents electrons outside said photodetector from migrating to said photodetector.

2. The CMOS active pixel image sensor in claim 1, wherein said scavenging diode is positioned adjacent said photodetector.

3. The CMOS active pixel image sensor in claim 1, wherein said photodetector is positioned adjacent sides and a top of each of said pixels and said active circuit components are positioned below said photodetector, wherein said scavenging diode is positioned along at least one of said sides of said pixels.

4. The CMOS active pixel image sensor in claim 1, wherein said scavenging diode is positioned directly between adjacent photodetectors.

5. The CMOS active pixel image sensor in claim 1, wherein said voltage source and said scavenging diode comprise a continuous conductor.

6. The CMOS active pixel image sensor in claim 1, further comprising an isolation region between adjacent pixels, wherein said scavenging diode is positioned below said isolation region.

7. A complementary metal oxide semiconductor (CMOS) active pixel image sensor, comprising an array of pixels, at least one of said pixels comprising:

a photodetector;

active circuit components adapted to read signals from said photodetector;

a first voltage source supplying voltage to said circuit components; and

a scavenging diode connected to a second voltage source, separate from said first voltage source,

wherein said scavenging diode prevents electrons outside said photodetector from migrating to said photodetector.

8. The CMOS active pixel image sensor in claim 7, wherein said scavenging diode is positioned adjacent said photodetector.

9. The CMOS active pixel image sensor in claim 7, wherein said photodetector is positioned adjacent sides and a top of each of said pixels and said active circuit components are positioned below said photodetector, wherein said scavenging diode is positioned along at least one of said sides of said pixels.

10. The CMOS active pixel image sensor in claim 7, wherein said scavenging diode is positioned directly between adjacent photodetectors.

11. The CMOS active pixel image sensor in claim 7, further comprising an isolation region between adjacent pixels, wherein said scavenging diode is positioned below said isolation region.

12. A camera/imaging system having a complementary metal oxide semiconductor (CMOS) active pixel image sensor, comprising an array of pixels, at least one of said pixels comprising:

a photodetector;

active circuit components adapted to read signals from said photodetector;

a voltage source supplying voltage to said circuit components; and

a scavenging diode connected to said voltage source,

wherein said scavenging diode prevents electrons outside said photodetector from migrating to said photodetector.

13. The camera/imaging system in claim 12, wherein said scavenging diode is positioned adjacent said photodetector.

14. The camera/imaging system in claim 12, wherein said photodetector is positioned adjacent sides and a top of each of said image sensors and said active circuit components are positioned below said photodetector, wherein said scavenging diode is positioned along at least one of said sides of said pixels.

15. The camera/imaging system in claim 12, wherein said scavenging diode is positioned directly between adjacent photodetectors.

16. The camera/imaging system in claim 12, wherein said voltage source and said scavenging diode comprise a continuous conductor.

17. A camera/imaging system having a complementary metal oxide semiconductor (CMOS) active pixel image sensor, comprising an array of pixels, at least one of said pixels comprising:

a photodetector;

active circuit components adapted to read signals from said photodetector;

a first voltage source supplying voltage to said circuit components; and

a scavenging diode connected to a second voltage source, separate from said first voltage source,

wherein said scavenging diode prevents electrons outside said photodetector from migrating to said photodetector.

18. The camera/imaging system in claim 17, wherein said scavenging diode is positioned adjacent said photodetector.

19. The camera/imaging system in claim 17, wherein said photodetector is positioned adjacent sides and a top of each of said pixels and said active circuit components are positioned below said photodetector, wherein said scavenging diode is positioned along at least one of said sides of said pixels.

20. The camera/imaging system in claim 17, wherein said scavenging diode is positioned directly between adjacent photodetectors.

21. The camera/imaging system in claim 17, further comprising an isolation region between adjacent pixels, wherein said scavenging diode is positioned below said isolation region.

22. A complementary metal oxide semiconductor (CMOS) active pixel image sensor, comprising an array of pixels, at least one of said pixels comprising:

a substrate having a first conductivity;

a photodetector region within said substrate having a second conductivity; and

a scavenging diode region within said substrate having said second conductivity, said scavenging diode region being positioned and between adjacent photodetector regions, such that said scavenging diode prevents electrons outside said photodetector region from migrating to said photodetector region.

23. The CMOS active pixel image sensor in claim 22, wherein said scavenging diode region is positioned directly between said adjacent photodetector regions.

24. The CMOS active pixel image sensor in claim 22, further comprising a voltage source connected to said scavenging diode region.

25. The CMOS active pixel image sensor in claim 22, further comprising isolation regions between said adjacent photodetector regions, wherein said scavenging diode is positioned between said isolation regions.

26. The CMOS active pixel image sensor in claim 22, further comprising an isolation region between said adjacent photodetector regions, wherein said scavenging diode is positioned below said isolation region.