Visible/near infrared image sensor array

• US 7,436,038 B2
• Filed: 02/23/2004
• Issued: 10/14/2008
• Est. Priority Date: 02/05/2002
• Status: Expired due to Fees

• Current Assignee: C-Phocus
• Original Assignee: e-Phocus, Inc.
• Inventors: Martin, Peter, Engelmann, Michael G., Hsieh, Tzu-Chiang, Pender, Milam, Chao, Calvin
• Primary Examiner(s): Pert; Evan
• Assistant Examiner(s): Tran; Tan N
• Application Number:
  US10/785,833
• Publication Number:
  US 20050104089A1
• Time in Patent Office: 1,695 Days
• Field of Search: 257/118, 257/222, 257/229, 257/233, 257/234, 257/257, 257/258, 257/290, 257/291, 257/292, 257/461, 257/462, 257/444, 257/E27.133
• US Class Current: 257/444
• CPC Class Codes: G01J 2005/0077 Imaging
• CPC Class Codes: G01J 5/02 Constructional details
• CPC Class Codes: G01J 5/024 Special manufacturing steps or sacrificial layers or layer structures
• CPC Class Codes: G01J 5/026 Control of working procedures of a pyrometer, other than calibration; Bandwidth calculation; Gain control
• CPC Class Codes: G01J 5/04 Casings
• CPC Class Codes: G01J 5/046 Materials; Selection of thermal materials
• CPC Class Codes: G01J 5/22 Electrical features thereof
• CPC Class Codes: G01J 5/52 using comparison with reference sources, e.g. disappearing-filament pyrometer
• 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 27/14621 Colour filter arrangements
• CPC Class Codes: H01L 27/1463 Pixel isolation structures
• CPC Class Codes: H01L 27/14632 Wafer-level processed structures
• CPC Class Codes: H01L 27/14636 Interconnect structures
• CPC Class Codes: H01L 27/14643 Photodiode arrays; MOS imagers
• CPC Class Codes: H01L 27/14645 Colour imagers
• CPC Class Codes: H01L 27/14649 Infrared imagers
• CPC Class Codes: H01L 27/14687 Wafer level processing
• CPC Class Codes: H01L 27/14689 MOS based technologies
• CPC Class Codes: H01L 27/14692 Thin film technologies, e.g. amorphous, poly, micro- or nanocrystalline silicon
• CPC Class Codes: H01L 31/03685 including microcrystalline silicon, uc-Si
• CPC Class Codes: H01L 31/03687 : including microcrystalline AIVBIV alloys, e.g. uc-SiGe, uc-SiC
• CPC Class Codes: H01L 31/1055 : the devices comprising amorphous materials of Group IV of the Periodic Table
• CPC Class Codes: H01L 31/109 : the potential barrier being of the PN heterojunction type
• CPC Class Codes: H01L 31/113 : being of the conductor-insulator-semiconductor type, e.g. metal-insulator-semiconductor field-effect transistor
• CPC Class Codes: H04N 23/11 : for generating image signals from visible and infrared light wavelengths
• CPC Class Codes: H04N 23/71 : Circuitry for evaluating the brightness variation
• CPC Class Codes: H04N 23/73 : by influencing the exposure time
• CPC Class Codes: H04N 25/67 : applied to fixed-pattern noise, e.g. non-uniformity of response
• CPC Class Codes: H04N 25/671 : for non-uniformity detection or correction
• CPC Class Codes: H04N 25/75 : Circuitry for providing, modifying or processing image signals from the pixel array
• CPC Class Codes: H04N 25/76 : Addressed sensors, e.g. MOS or CMOS sensors
• CPC Class Codes: H04N 25/772 : comprising A/D, V/T, V/F, I/T or I/F converters
• CPC Class Codes: H04N 5/33 : Transforming infrared radiation cameras or camera modules for generating image signals from infrared radiation H04N23/20; circuitry of SSIS for transforming infrared radiation into image signals H04N25/20
• CPC Class Codes: Y02E 10/545 : Microcrystalline silicon PV cells
• CPC Class Codes: Y02E 10/548 : Amorphous silicon PV cells

Abstract

A MOS or CMOS sensor for high performance imaging in broad spectral ranges including portions of the infrared spectral band. These broad spectral ranges may also include portions or all of the visible spectrum, therefore the sensor has both daylight and night vision capabilities. The sensor includes a continuous multi-layer photodiode structure on a many pixel MOS or CMOS readout array where the photodiode structure is chosen to include responses in the near infrared spectral ranges. A preferred embodiment incorporates a microcrystalline copper indium diselenide/cadmium sulfide photodiode structure on a CMOS readout array. An alternate preferred embodiment incorporates a microcrystalline silicon germanium photodiode structure on a CMOS readout array. Each of these embodiments provides night vision with image performance that greatly surpasses the GEN III night vision technology in terms of enhanced sensitivity, pixel size and pixel count. Further advantages of the invention include low electrical bias voltages, low power consumption, compact packaging, and radiation hardness. In special preferred embodiments CMOS stitching technology is used to provide multi-million pixel focal plane array sensors. One embodiments of the invention made without stitching is a two-million pixel sensor. Other preferred embodiments available using stitching techniques include sensors with 250 million (or more) pixels fabricated on a single wafer. A particular application of these very high pixel count sensors is as a focal plane array for a rapid beam steering telescope in a low earth orbit satellite useful for tracking over a 1500-meter wide track with a resolution of 0.3 meter.

Claims

1. A MOS or CMOS based visible/near infrared sensor array comprising:

A) a substrate,

B) a plurality of MOS or CMOS pixel circuits fabricated in or on said substrate, each pixel circuit comprising;

1) a charge collecting electrode for collecting electrical charges and

2) a plurality of transistors for monitoring periodically charges collected by said charge collecting electrode,

C) a continuous un-pixelated photodiode layer of charge generating material located above said pixel circuits for converting into electrical charges electromagnetic radiation in the visible and near infrared spectral ranges, said photodiode layer comprising at least an n-layer, an intrinsic layer and a p-layer,

wherein each of the n-layer, the intrinsic layer and the p-layer of the continuous un-pixelated photodiode layer are continuous with no gaps between pixels, and

wherein one of said n-layer or said p-layer is adjacent to the charge collecting electrodes in each of the pixel circuits to define a bottom layer; and

wherein the bottom layer comprises sufficient carbon to increase its electrical resistance to more than 2×

10⁷ ohm-cm to minimize pixel-to-pixel crosstalk; and

D) a surface electrode in the form of a grid or thin transparent layer located above said layer of charge generating material.

2. The sensor as in claim 1 wherein said charge generating material also converts electromagnetic radiation in ultraviolet spectral ranges into electrical charges.

3. The sensor as in claim 2 wherein said surface electrode is comprised of indium tin and oxygen.

4. The sensor as in claim 2 wherein said plurality of pixel circuits in at least 2 million CMOS pixel circuits.

5. The sensor as in claim 1 wherein one of the said intrinsic layer comprises microcrystalline silicon.

6. The sensor as in claim 5 wherein said microcrystalline layer is grown using a radio frequency plasma enhanced chemical vapor deposition process.

7. The sensor as in claim 1 wherein the said intrinsic layer is comprised entirely of microcrystalline silicon.

8. The sensor as in claim 1 wherein said p-layer is comprised of copper selenium and indium and said n-layer is comprised of cadmium and sulfur.

9. The sensor as in claim 8 wherein said p-layer also comprises gadolinium.

10. The sensor as in claim 9 wherein said n-layer is on top of said p-layer.

11. The sensor as in claim 10 wherein said p-layer is deposited from a four crucible vapor.

12. The sensor as in claim 1 wherein said photodiode layer comprises geranium.

13. The sensor as in claim 1 wherein said photodiode layer comprises microcrystalline germanium.

14. The sensor as in claim 1 wherein said surface electrode is comprised of indium tin and oxygen.

15. The sensor as in claim 1 wherein said p-layer is located adjacent to said surface electrode.

16. The sensor as in claim 1 wherein said plurality of pixel circuits in at least 2 million CMOS pixel circuits.

17. The sensor as in claim 1 wherein said plurality of pixel circuits in at least 100 million CMOS pixel circuits.

18. The sensor as in claim 1 wherein said pixel circuits are located on a single wafer and are comprised of pixels produced in die spots that are lithographically stitched together to form a unitary pixel array of more than 50 million pixels.

19. The sensor as in claim 18 wherein said array of more than 50 million pixels is an array of more than 100 million pixels.

20. An array as in claim 1 and also comprising data analyzing circuits fabricated on said substrate.

21. An array as in claim 1 wherein said sensor is configured with a Column-Parallel Analog-to Digital architecture.

22. An array as in claim 1 where said array is a component of a video camera and said array further comprises two 10-bit output ports representing video output from columns and odd columns respectively.

23. An array as in claim 1 wherein said surface electrode is comprised of a layer of indium tin oxide.

24. An array as in claim 1 and further comprising an array of color filters located on top of said surface electrode.

25. An array as in claim 24 wherein said color filters are comprised of red, green and blue filters arranged in four color quadrants of two green, one red and one blue.

26. An array as in claim 1 wherein said array is a part of a camera incorporated into a device chosen from the following group:

Analog camcorder Digital camcorder Security camera Digital still camera Personal computer camera Toy Military unmanned aircraft, bomb and missile Sports equipment High definition television camera Telescope ROBS Telescope.