Antiblooming imaging apparatus, systems, and methods

• US 9,029,924 B2
• Filed: 01/16/2012
• Issued: 05/12/2015
• Est. Priority Date: 11/28/2006
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Xu, Chen, Agranov, Gennadiy, Karasev, Igor
• Primary Examiner(s): Moore, Whitney T
• Assistant Examiner(s): GALVIN III, JOSEPH M
• Application Number:
  US13/351,106
• Publication Number:
  US 20120119317A1
• Time in Patent Office: 1,212 Days
• Field of Search: 257/230, 257/292, 257/443, 257/445, 257/E27.127, 257/E27.133
• US Class Current: 257/292
• CPC Class Codes: H04N 25/623 by evacuation via the output or reset lines
• CPC Class Codes: H04N 25/75 Circuitry for providing, modifying or processing image signals from the pixel array
• CPC Class Codes: H04N 25/77 Pixel circuitry, e.g. memories, A/D converters, pixel amplifiers, shared circuits or shared components

Abstract

Apparatus, systems, and methods are described to assist in reducing dark current in an active pixel sensor. In various embodiments, a potential barrier arrangement is configured to block the flow of charge carriers generated outside a photosensitive region. In various embodiments, a potential well-potential barrier arrangement is formed to direct charge carriers away from the photosensitive region during an integration time.

Claims

1. A pixel sensor, comprising:

a plurality of light conversion regions, each light conversion region having dopants disposed in the respective light conversion region according to a first dopant profile, the respective light conversion region having a first potential barrier based on the first dopant profile, the first potential barrier having a first height;

a plurality of charge carrier blocking regions, each one of the plurality of charge carrier blocking regions operatively coupled and adjacent to one of the plurality of light conversion regions, each charge carrier blocking region having dopants disposed in the respective charge carrier blocking region according to a second dopant profile, the adjacent light conversion region having a second potential barrier opposite the first potential barrier, the second potential barrier having a second height based on the second dopant profile, the second height being greater than the first height;

a plurality of charge removal regions, each charge removal region having a structure to trap charge carriers in conjunction with an arrangement of the structure with a respective charge carrier blocking region of the plurality of charge carrier blocking regions, the structure arranged to operatively transfer the charge carriers to at least one potential well with an energy above a specified threshold potential.

2. The pixel sensor of claim 1, wherein the plurality of light conversion regions, the plurality of charge carrier blocking regions, and the plurality of charge removal regions are disposed in a semiconductor region comprising one or more of SiC, SiGeC, GaAs, AlAs, AlGaAs, InP, InGaAs, InAs, ZnSe, ZnS, GaN, GaP, AlP, AlGaP, AlAsP, GaAsP, InAsP, AlGaN, AN, AlInAs, GaInN, GaAsN, GaPN, AlGaAsP, AlGaInAsP, or AlGaInAsPN.

3. The pixel sensor of claim 2, wherein the semiconductor region is lattice matched to a substrate on which it is disposed.

4. The pixel sensor of claim 1, wherein the plurality of charge removal regions includes a potential energy barrier with in-band electronic states configured to couple the charge carriers to a charge carrier sink.

5. The pixel sensor of claim 1, wherein at least one of the plurality of light conversion regions is configured to receive light passing through at least one of a shutter, a filter, or a lens.

6. The pixel sensor of claim 1, wherein at least one of the plurality of light conversion regions has absorption properties to absorb light having a plurality of wavelength bands.

7. The pixel sensor of claim 1, wherein the pixel sensor includes:

a substrate on which the light conversion regions are disposed; and

for each light conversion region, a filter layer on a side of the substrate opposite the respective light conversion region.

8. The pixel sensor of claim 1, wherein the plurality of charge blocking regions are configured to block charge carriers generated outside the plurality of light conversion regions.

9. The pixel sensor of claim 1, wherein the plurality of light conversion regions has absorption properties to absorb light associated with heat.

10. The pixel sensor of claim 1, wherein the plurality of light conversion regions is configured to receive light passing through at least one of a shutter, a filter, or a lens and the plurality of light conversion regions has absorption properties to absorb light associated with heat.

11. The pixel sensor of claim 1, wherein at least one of the plurality of light conversion regions has absorption properties to absorb light having a plurality of wavelength bands and the plurality of light conversion regions has absorption properties to absorb light associated with heat.

12. The pixel sensor of claim 1, wherein the plurality of light conversion regions are configured to store photogenerated charge carriers during a specified charge carrier accumulation time and the plurality of charge blocking regions are configured to block charge carriers generated outside the plurality of light conversion regions.

13. The pixel sensor of claim 1, wherein the pixel sensor includes a control operatively coupled to the light conversion regions, the charge carrier blocking regions, and the charge removal regions, the control arranged to control the direction of charge carriers away from the light conversion region.

14. The pixel sensor of claim 1, wherein the plurality of light conversion regions is configured to receive light passing through at least one of a shutter, a filter, or a lens and configured to store photogenerated charge carriers during a specified charge carrier accumulation time.

15. The pixel sensor of claim 1, wherein the plurality of light conversion regions has absorption properties to absorb light having a plurality of wavelength bands and configured to store photogenerated charge carriers during specified charge carrier accumulation time.

16. The pixel sensor of claim 1, wherein each light conversion region of the plurality of light conversion regions is disposed below a transparent photogate.

17. The pixel sensor of claim 1, wherein each light conversion region of the plurality of light conversion regions is disposed with a filter layer and an antireflection layer between the light conversion region and a transparent photogate to the respective light conversion region.