MATERIALS, SYSTEMS AND METHODS FOR OPTOELECTRONIC DEVICES

• US 20100187408A1
• Filed: 03/19/2010
• Published: 07/29/2010
• Est. Priority Date: 04/18/2007
• Status: Active Grant

• Current Assignee: InVisage Technologies, Inc. (Apple Inc.)
• Original Assignee: InVisage Technologies, Inc. (Apple Inc.)
• Inventors: Konstantatos, Gerasimos, Klem, Ethan Jacob Dukenfield, Brading, Michael Charles, Tang, Jiang, Sargent, Edward Hartley, Tian, Hui, Macneil, Dean Delehanty
• Granted Patent: US 8,013,412 B2
• Time in Patent Office: Days
• US Class Current: 250/214.100
• CPC Class Codes: G06V 40/1318 using electro-optical elements or layers, e.g. electroluminescent sensing
• CPC Class Codes: H01L 27/14601 Structural or functional details thereof
• CPC Class Codes: H01L 27/14603 Special geometry or disposition of pixel-elements, address-lines or gate-electrodes
• 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 27/14641 Electronic components shared by two or more pixel-elements, e.g. one amplifier shared by two pixel elements
• CPC Class Codes: H01L 27/14647 Multicolour imagers having a stacked pixel-element structure, e.g. npn, npnpn or MQW elements
• CPC Class Codes: H01L 27/14652 Multispectral infrared imagers, having a stacked pixel-element structure, e.g. npn, npnpn or MQW structures
• CPC Class Codes: H01L 27/14687 Wafer level processing
• CPC Class Codes: H01L 27/14692 Thin film technologies, e.g. amorphous, poly, micro- or nanocrystalline silicon
• CPC Class Codes: H01L 31/036 characterised by their crystalline structure or particular orientation of the crystalline planes
• CPC Class Codes: H01L 31/1013 devices sensitive to two or more wavelengths, e.g. multi-spectrum radiation detection devices

Abstract

A photodetector is described along with corresponding materials, systems, and methods. The photodetector comprises an integrated circuit and at least two optically sensitive layers. A first optically sensitive layer is over at least a portion of the integrated circuit, and a second optically sensitive layer is over the first optically sensitive layer. Each optically sensitive layer is interposed between two electrodes. The two electrodes include a respective first electrode and a respective second electrode. The integrated circuit selectively applies a bias to the electrodes and reads signals from the optically sensitive layers. The signal is related to the number of photons received by the respective optically sensitive layer.

Claims

1. A photodetector comprising:

an integrated circuit;

at least two optically sensitive layers, a first optically sensitive layer and a second optically sensitive layer, the first optically sensitive layer over at least a portion of the integrated circuit and the second optically sensitive layer over the first optically sensitive layer;

a plurality of electrodes including at least two electrodes between which the two optically sensitive layers are interposed, the electrodes including a respective first electrode and a respective second electrode; and

circuitry coupled to the integrated circuit, the circuitry outputting signals from the optically sensitive layers, the signals corresponding to light absorbed by the optically sensitive layers.

2. The photodetector of claim 1, wherein the integrated circuit includes the circuitry.

3. The photodetector of claim 1, wherein the circuitry comprises bias circuitry that selectively applies a bias and reads from the optically sensitive layers pixel information corresponding to the light absorbed by the optically sensitive layers.

4. The photodetector of claim 1, wherein the circuitry comprises conversion circuitry.

5. The photodetector of claim 4, wherein the conversion circuitry converts the signals from a first type to a second type.

6. The photodetector of claim 4, wherein the conversion circuitry converts the signals from analog signals to digital signals.

7. The photodetector of claim 4, wherein the conversion circuitry converts the signals from digital signals to analog signals.

8. The photodetector of claim 1, wherein the circuitry comprises compensation circuitry.

9. The photodetector of claim 8, wherein the compensation circuitry adjusts the signal to compensate for different properties among the optically sensitive layers.

10. The photodetector of claim 8, wherein the compensation circuitry at least partially compensates for nonlinearity of signals output from the optically sensitive layers.

11. The photodetector of claim 8, wherein the compensation circuitry at least partially linearizes digital data derived from the signals.

12. The photodetector of claim 8, wherein the compensation circuitry at least partially linearizes the signals using a polynomial function.

13. The photodetector of claim 8, wherein the compensation circuitry at least partially linearizes the signals using piecewise linear inversion of a relationship between intensity of the light and electrical properties of at least one optically sensitive layer.

14. The photodetector of claim 8, wherein the compensation circuitry at least partially compensates for variance in a rate of current flow in at least one optically sensitive layer over an integration period for a constant intensity of light.

15. The photodetector of claim 8, wherein the compensation circuitry at least partially compensates for variance in a rate of current flow in at least one optically sensitive layer over an integration period for differing intensities of light.

16. The photodetector of claim 8, wherein the compensation circuitry at least partially compensates for variance in gain in at least one optically sensitive layer over an integration period for a constant intensity of light.

17. The photodetector of claim 8, wherein the compensation circuitry at least partially compensates for variance in gain in at least one optically sensitive layer over an integration period for differing intensities of light.

18. The photodetector of claim 8, wherein the compensation circuitry:

at least partially compensates for nonlinearity of signals output from the optically sensitive layers; and

at least partially compensates for a difference between dark currents of signals output from the optically sensitive layers.

19. The photodetector of claim 8, wherein the compensation circuitry includes a read out circuit and demosaicing algorithm that outputs a corrected color matrix based on analog quantities read out from the respective optically sensitive layers.

20. The photodetector of claim 19, wherein the corrected color matrix includes a red, green, blue (RGB) matrix.

21. The photodetector of claim 8, wherein the compensation circuitry compensates for transmission leakage between layers.

22. The photodetector of claim 8, wherein the compensation circuitry includes image circuitry to generate image data.

23. The photodetector of claim 22, wherein the first optically sensitive layer comprises a nanocrystal material having first photoconductive gain and the second optically sensitive layer comprises a nanocrystal material having a second photoconductive gain, the image circuitry compensating for a difference between the first photoconductive gain and the second photoconductive gain.

24. The photodetector of claim 8, wherein the compensation circuitry applies black level correction that compensates for a difference between dark currents among the at least two optically sensitive layers by applying a plurality of dark current compensations to the signal.

25. The photodetector of claim 24, wherein the compensation circuitry applies a first dark current compensation to a first signal from the first optically sensitive layer and a second dark current compensation to a second signal from the second optically sensitive layer.

26. The photodetector of claim 25, wherein the first dark current compensation is different from the second dark current compensation.

27. The photodetector of claim 24, comprising at least one black pixel.

28. The photodetector of claim 27, wherein the at least one black pixel comprises at least two optically sensitive opaque layers, a first optically sensitive opaque layer and a second optically sensitive opaque layer, the first optically sensitive opaque layer and the second optically sensitive opaque layer each comprising an optically sensitive layer covered with an opaque material, the first optically sensitive opaque layer over at least a portion of a black pixel integrated circuit and the second optically sensitive opaque layer over the first optically sensitive opaque layer, wherein each optically sensitive opaque layer is interposed between a respective first electrode of the black pixel and a respective second electrode of the black pixel, wherein the integrated circuit selectively applies a bias to the respective first and second electrodes of the black pixel and reads a dark current signal from the optically sensitive opaque layers, wherein the dark current signal is related to the number of photons received by the respective optically sensitive opaque layer.

29. The photodetector of claim 27, wherein the black pixel generates a dark current.

30. The photodetector of claim 29, wherein the dark current density is approximately in a range of 10 nanoamps (nA)/square centimeter (cm) to 500 nA/square cm.

31. The photodetector of claim 29, wherein the dark current compensations include subtracting the dark current from the signals of the optically sensitive layers in different proportions.

32. The photodetector of claim 31, wherein the dark current compensations include subtracting a first portion of the dark current from a first signal of the second optically sensitive layer and subtracting a second portion of the dark current from a second signal of the second optically sensitive layer.

33. The photodetector of claim 32, wherein the first portion is larger than the second portion.

34. The photodetector of claim 27, wherein the at least one black pixel comprises a first black pixel corresponding to the first optically sensitive layer and a second black pixel corresponding to the second optically sensitive layer.

35. The photodetector of claim 34, wherein the first black pixel generates a first dark current and the second black pixel that generates a second dark current.

36. The photodetector of claim 35, wherein the dark current compensation includes subtracting the first dark current from a first signal of the first optically sensitive layer and subtracting the second dark current from a second signal of the second optically sensitive layer.

37. The photodetector of claim 27, wherein the at least one black pixel comprises a plurality of black pixels generating a plurality of dark currents, wherein the compensation circuitry generates the plurality of dark current compensations from the plurality of dark currents.

38. The photodetector of claim 24, wherein responsivities of each of the optically sensitive layers are approximately equal when a thickness of the second optically sensitive layer is less than a thickness of the first optically sensitive layer.

39. The photodetector of claim 24, wherein the circuitry comprises bandgap reference circuitry.

40. The photodetector of claim 39, wherein the black level correction is based on temperature monitoring by tracking a voltage from the bandgap reference circuitry.