Claims
- 1. An active pixel formed in a semiconductor substrate comprising:
a field oxide (FOX) region formed on said substrate defining an active area; a photodiode formed in said semiconductor substrate, a first portion of said photodiode being formed underneath said FOX region; an output node formed within said active area and adjacent to said photodiode; and a transfer gate formed over said substrate and between said output node and said photodiode, further wherein said transfer gate is formed on top of a second portion of said photodiode, such that substantially the entire surface of the photodiode is covered by either the transfer gate or the FOX region.
- 2. The active pixel of claim 1 further including a reset transistor formed within said active area, said reset transistor having a gate formed between said output node and a voltage reference (VREF).
- 3. The active pixel of claim 1 wherein said FOX region is formed from local oxidation of silicon.
- 4. The active pixel of claim 1 wherein said FOX region is formed by shallow trench isolation.
- 5. The active pixel of claim 1 wherein said substrate is a P-type substrate and said output node is a N+ region.
- 6. The active pixel of claim 1 wherein said output node is formed within a P-well formed in said P-type substrate.
- 7. The active pixel of claim 6 wherein said P-well is separated from said photodiode by a gap.
- 8. The active pixel of claim 6 wherein said photodiode is formed by an N-well formed in said P-type substrate.
- 9. The active pixel of claim 1 further including a surface N+ region underneath said transfer gate and adjoining said photodiode.
- 10. The active pixel of claim 1 further including a pixel output transistor formed within said active area and having its gate connected to said output node.
- 11. The active pixel of claim 10 further including a row select transistor formed within said active area and connected to the drain of said pixel output transistor.
- 12. A pixel formed in a substrate for use in a CMOS image sensor comprising:
a photodiode formed from the junction of a first top portion of said substrate having a first conductivity type and a second bottom portion of said substrate having a second conductivity type, the first top portion being substantially covered by a field oxide (FOX) region; an output node formed in said substrate; a transfer gate formed on said substrate between said output node and said photodiode, said transfer gate in combination with said FOX region covering substantially all of said first top portion; a reset transistor coupled between said output node and a voltage reference (VREF) for resetting the output node; and a pixel output transistor having its gate coupled to the output node.
- 13. The pixel of claim 12 wherein said FOX region is formed from local oxidation of silicon.
- 14. The pixel of claim 12 wherein said FOX region is formed by shallow trench isolation.
- 15. A CMOS image sensor comprising:
a plurality of active pixels arranged in rows and columns, at least one of said active pixels comprising:
(a) a field oxide (FOX) region formed on said substrate defining an active area; (b) a photodiode formed in said semiconductor substrate, a first portion of said photodiode being formed underneath said FOX region; (c) an output node formed within said active area and adjacent to said photodiode; and (d) a transfer gate formed over said substrate and between said output node and said photodiode, further wherein said transfer gate is formed on top of a second portion of said photodiode, such that substantially the entire surface of the photodiode is covered by either the transfer gate or the FOX region; a processing circuit for receiving the output of said active pixels; and an I/O circuit for outputting the output of said active pixels off of said CMOS image sensor.
- 16. The image sensor of claim 15 further said active pixel further includes a reset transistor formed within said active area, said reset transistor having a gate formed between said output node and a voltage reference (VREF).
- 17. The image sensor of claim 15 wherein said FOX region is formed from local oxidation of silicon.
- 18. The image sensor of claim 15 wherein said FOX region is formed by shallow trench isolation.
- 19. The image sensor of claim 15 wherein said substrate is a P-type substrate and said output node is a N+ region.
- 20. The image sensor of claim 15 wherein said output node is formed within a P-well formed in said P-type substrate.
- 21. The image sensor of claim 20 wherein said photodiode is formed by an N-well formed in said P-type substrate.
- 22. The image sensor of claim 15 wherein said active pixel further includes a surface N+ region underneath said transfer gate and adjoining said photodiode.
- 23. The image sensor of claim 15 wherein said active pixel further includes a pixel output transistor formed within said active area and having its gate connected to said output node.
- 24. The image sensor of claim 23 wherein said active pixel further includes a row select transistor formed within said active area and connected to the drain of said pixel output transistor.
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application is a continuation application of U.S. patent application Ser. No. 10/011,589, filed on Nov. 6, 2001, which is hereby incorporated by reference in its entirety.
Continuations (1)
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Number |
Date |
Country |
Parent |
10011589 |
Nov 2001 |
US |
Child |
10218762 |
Aug 2002 |
US |