Image sensor with microcrystalline germanium photodiode layer

• US 7,276,749 B2
• Filed: 02/24/2006
• Issued: 10/02/2007
• Est. Priority Date: 02/05/2002
• Status: Expired due to Fees

• Current Assignee: e-Phocus, Inc.
• Original Assignee: e-Phocus, Inc.
• Inventors: Martin, Peter, Chao, Calvin, Engelman, Michael G., Hsieh, Teu Chiang, Pender, Milan
• Primary Examiner(s): Pert; Evan
• Assistant Examiner(s): TRAN, TAN N
• Application Number:
  US11/361,426
• Publication Number:
  US 20060267054A1
• Time in Patent Office: 585 Days
• Field of Search: None
• US Class Current: 257/292
• CPC Class Codes: H01L 27/14632 Wafer-level processed structures
• CPC Class Codes: H01L 27/14643 Photodiode arrays; MOS imagers
• CPC Class Codes: H01L 27/14687 Wafer level processing
• CPC Class Codes: H01L 31/0322 comprising only AIBIIICVI chalcopyrite compounds, e.g. Cu In Se2, Cu Ga Se2, Cu In Ga Se2
• CPC Class Codes: H01L 31/03682 including only elements of Group IV of the Periodic Table
• CPC Class Codes: H01L 31/105 the potential barrier being of the PIN type
• CPC Class Codes: H01L 31/1055 the devices comprising amorphous materials of Group IV of the Periodic Table
• CPC Class Codes: H01L 31/1808 including only Ge
• CPC Class Codes: Y02E 10/541 CuInSe2 material PV cells
• CPC Class Codes: Y02E 10/546 Polycrystalline silicon PV cells

Abstract

A microcrystalline germanium image sensor array. The array includes a number of pixel circuits fabricated in or on a substrate. Each pixel circuit comprises a charge collecting electrode for collecting electrical charges and a readout means for reading out the charges collected by the charge collecting electrode. A photodiode layer of charge generating material located above the pixel circuits convert electromagnetic radiation into electrical charges. This photodiode layer includes microcrystalline germanium and defines at least an n-layer, and i-layer and a p-layer. The sensor array also includes and a surface electrode in the form of a grid or thin transparent layer located above the layer of charge generating material. The sensor is especially useful for imaging in visible and near infrared spectral regions of the electromagnetic spectrum and provides imaging with starlight illumination.

Claims

1. A microcrystalline germanium image sensor array comprising:

A) a substrate,

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

1) a charge collecting electrode for collecting electrical charges and

2) a readout means for reading out charges collected by said charge collecting electrode,

C) a single continuous un-pixelated photodiode layer of charge generating material located above said pixel circuits for converting electromagnetic radiation into electrical charges, said single continuous un-pixelated photodiode layer comprising microcrystalline germanium and defining at least an n-layer, and i-layer and a p-layer, 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 array as in claim 1 wherein said pixel circuits are CCD circuits.

3. An array as in claim 2 wherein said array is incorporated in a night vision device.

4. An array as in claim 2 wherein said array is incorporated in a night vision device having a pixel count of at least about 480×

640.

5. An array as in claim 4 wherein said array is adapted to run at a frame rate of at least about 30 frames per second.

6. An array as in claim 4 wherein said array is adapted to run at a system clock rate at least about 12 MHz.

7. An array as in claim 4 wherein the device is a hybrid device combining a CCD readout array, a CCD-based interline transfer device and a CMOS charge amplification circuit that is ball bonded to a periphery of the CCD read-out array.

8. The sensor array as in claim 1 wherein said pixel circuits are MOS or CMOS circuits.

9. An array as in claim 8 wherein said array is incorporated in a night vision device.

10. The sensor as in claim 1 wherein said electromagnetic radiation includes visible and infrared radiation.

11. The sensor as in claim 10 wherein said electromagnetic radiation also includes ultraviolet radiation.

12. The sensor as in claim 1 wherein said photodiode layer comprising microcrystalline germanium is grown using a radio frequency plasma enhanced chemical vapor deposition process.

13. The sensor as in claim 1 wherein said microcrystalline geranium is deposited using radio frequency enhanced chemical vapor deposition.

14. The sensor as in claim 1 wherein said microcrystalline geranium is deposited using pulsed radio frequency enhanced chemical vapor deposition.

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

16. The sensor as in claim 1 wherein said n-layer is located adjacent to said charge collecting electrodes in said plurality of pixel circuits and said n-layer comprises carbon.

17. The sensor as in claim 1 wherein said sensor comprises a focal plane array of a telescope.

18. An array as in claim 1 where said array is a component of a video camera.

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

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

21. 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.

22. An array as in claim 1 wherein said readout means is a CCD readout array and further comprising MOS or CMOS charge amplification circuit.

23. An array as in claim 22 wherein said MOS or CMOS charge amplification circuit is bonded to the periphery of the CCD readout array.

24. An array as in claim 1 wherein said photodiode layer covers all of said plurality of pixel circuits.

25. An array as in claim 1 wherein said array is incorporated in a night vision device.