STACKED PHOTODIODE MULTISPECTRAL IMAGER

• US 20150129747A1
• Filed: 11/12/2014
• Published: 05/14/2015
• Est. Priority Date: 11/12/2013
• Status: Active Grant

• Current Assignee: Owl Autonomous Imaging, Inc.
• Original Assignee: Intrinsix Corp. (CEVA Incorporated)
• Inventors: Petilli, Eugene M.
• Granted Patent: US 9,595,558 B2
• Time in Patent Office: Days
• US Class Current: 250/208.1
• CPC Class Codes: H01L 27/14621 Colour filter arrangements
• CPC Class Codes: H01L 27/14627 Microlenses
• CPC Class Codes: H01L 27/14636 Interconnect structures
• CPC Class Codes: H01L 27/1464 Back illuminated imager structures
• CPC Class Codes: H01L 27/14647 Multicolour imagers having a stacked pixel-element structure, e.g. npn, npnpn or MQW elements
• CPC Class Codes: H04N 25/17 Colour separation based on photon absorption depth, e.g. full colour resolution obtained simultaneously at each pixel location

Abstract

A photodiode architecture comprises first, second, and third independent photodiodes, and a shared electrode. The first, second, and third photodiodes are each connected to respective sources of bias voltage and to a common shared electrode, whereby the photodiode architecture comprises at least one of a shared anode and shared cathode photodiode architecture. The photodiode architecture selectively reverse biases the first, second, and third photodiodes so that, during operation, at least one of the first, second and third photodiodes is always operating in a photoconducting mode, to enable capture and storage of charge from any photodiode in the architecture operating in photoconducting mode. Advantageously, the first photodiode can be configured to respond to a first wavelength of light and at least one of the second and third photodiodes can be configured to be responsive to a respective second or third wavelength of light shorter than the first wavelength of light.

Claims

1. A photodiode architecture, comprising:

a first photodiode comprising first and second electrodes, the second electrode being operably coupled to a first source of bias voltage at a first potential, the first electrode being coupled to a shared electrode;

a second photodiode operably connected in series with the first photodiode, the second photodiode being independent of the first photodiode, comprising third and fourth electrodes, the fourth electrode being operably coupled to a second source of bias voltage at the first potential, the third electrode being coupled to the shared electrode; and

a third photodiode operably connected in series with the first photodiode, the third photodiode being independent of the first photodiode and comprising fifth and sixth electrodes, the sixth electrode being operably coupled to a third source of bias voltage at the first potential and the fifth electrode being coupled to the shared electrode;

wherein the shared electrode node is in operable communication with the first electrode, third electrode, and fifth electrode;

wherein the photodiode architecture comprises at least one of a shared anode photodiode architecture and a shared cathode photodiode architecture, wherein the shared electrode node is configured to operate, respectively, as either a shared anode node or a shared cathode node for the respective first, second, and third photodiodes; and

wherein the first photodiode, second photodiode, third photodiode and shared electrode are constructed and arranged to selectively reverse bias the first, second, and third photodiodes so that, during operation, at least one of the first, second and third photodiodes is always operating in a photoconducting mode, to enable capture and storage of charge from any photodiode in the photodiode architecture that is operating in photoconducting mode.

2. The photodiode architecture of claim 1, wherein the photodiode architecture is configured as part of a front-side-illumination device.

3. The photodiode architecture of claim 1, wherein the photodiode architecture is configured as part of a back-side illumination device.

4. The photodiode architecture of claim 1, wherein the first photodiode is configured to respond to a first wavelength of light and at least one of the second and third photodiodes is configured to be responsive to a respective second or third wavelength of light that is shorter than the first wavelength of light.

5. The photodiode architecture of claim 1, wherein at least one of the first, second, and third photodiodes is configured to be responsive to non-visible light and at least one of the first, second and third photodiodes is configured to be responsive to visible light.

6. The photodiode architecture of claim 1, wherein the second and third photodiodes are each constructed and arranged to be responsive to a respective one of visible red light, visible green light, visible blue light, and visible panchromatic light.

7. The photodiode architecture of claim 1, wherein the first photodiode is constructed and arranged to be responsive to any one of infrared light, near infrared (NIR) light, short-wavelength infrared (SWIR) light, long wavelength infrared (LWIR) light, ultraviolet (UV) light, radio wave light, x-ray wave light, and gamma ray light.

8. The photodiode architecture of claim 1, wherein any two of the first, second, and third photodiodes are responsive to the same type of light.

9. The photodiode architecture of claim 1, further comprising a color filter array (CFA) configured to be in operable communication with the first, second, and third photodiodes.

10. The photodiode architecture of claim 1, wherein the first, second, and third photodiodes are arranged in a stacked configuration.

11. The photodiode architecture of claim 1, wherein the photodiode architecture is implemented as part of at least one of an image capture device and an image fusion system.

12. A multispectral pixel device, comprising

a non-visible pixel layer, the non-visible pixel layer comprising a layer of semiconductor material constructed and arranged to be responsive to at least a first type of non-visible light and also comprising a first electrode coupled to a first bias voltage;

a shared electrode layer formed on top of at least a portion of the non-visible pixel layer, the electrode comprising one of a cathode and an anode, the shared electrode layer formed so as to leave at least a portion of the non-visible pixel layer exposed, the shared electrode layer comprising a layer of semiconductor material constructed and arranged to provide an electrode layer shareable by the non-visible pixel layer and a multicolored pixel layer;

a multicolored pixel layer formed on top of at least a portion of the shared electrode layer, the multicolored pixel layer formed so as to leave at least a portion of the shared electrode layer exposed, the multicolored pixel layer sharing an electrode with the non-visible pixel layer, wherein the multicolored pixel layer comprises;

a first pixel portion comprising a first region of material that is responsive to a first type of visible light, the first pixel region further comprising a respective first pixel electrode, the first pixel electrode comprising at least one of an anode and a cathode, wherein the first pixel electrode comprises a different type of electrode than the shared electrode, the first pixel electrode operably coupled to a respective source of first pixel bias voltage; and

a second pixel portion, the second pixel portion comprising a second pixel region of material that is responsive to a second type of visible light, the second pixel region further comprising a respective second pixel electrode, the second pixel electrode being the same type of electrode as the first pixel electrode and being operably coupled to a respective source of second pixel bias voltage;

wherein the nonvisible pixel layer, multicolored pixel layer, and shared electrode layer are constructed and arranged so that, during operation, at least one photodiode formed in the nonvisible pixel layer and multicolored pixel layer is always operating in a photoconducting mode, to enable capture and storage of charge for the photodiode in the device that is operating in photoconducting mode.

13. The multispectral pixel device of claim 12, further comprising a color filter array (CFA) layer operably configured to be in operable communication with the multicolored pixel layer.

14. The multispectral pixel device of claim 12 further comprising a plurality of multispectral pixel devices arranged in an array.

15. The multispectral pixel device of claim 12, wherein the CFA comprises a Red, Green, Black, White (RGBW) PANchromatic filter.

16. The multispectral pixel device of claim 12, wherein the non-visible pixel layer comprises:

a layer of semiconductor material, the material comprising at least one of n-type material and p-type material, wherein the semiconductor material is responsive to non-visible light, the non-visible light selected from the group consisting of infrared light, near infrared (NIR) light, short-wavelength infrared (SWIR) light, long wavelength infrared (LWIR) light, ultraviolet (UV) light, radio wave light, x-ray wave light, and gamma ray light.

17. The multispectral pixel device of claim 12, wherein the multicolored pixel layer comprises:

a red pixel portion, the red pixel portion comprising a first region of semiconductor material, the semiconductor material comprising one of n-type and p-type material, the semiconductor material being responsive to visible red light, the red pixel region further comprising a respective red electrode, the red electrode comprising one of an anode and a cathode and being operably coupled to a respective source of red pixel bias voltage;

a green pixel portion, the green pixel portion comprising a second region of semiconductor material, the semiconductor material comprising one of n-type and p-type material, the semiconductor material being responsive to visible green light, the green pixel region further comprising a respective green electrode, the green anode comprising one of an anode and a cathode and being operably coupled to a respective source of green pixel bias voltage;

a blue pixel portion, the blue pixel portion comprising a third region of semiconductor material, the semiconductor material comprising one of n-type and p-type material, the semiconductor material being responsive to visible blue light, the blue pixel region further comprising a respective blue electrode, the blue electrode comprising one of an anode and a cathode and being operably coupled to a respective source of blue pixel bias voltage; and

a panchromatic pixel portion, the panchromatic pixel portion comprising a fourth region of semiconductor material, the semiconductor material comprising one of n-type and p-type material, the semiconductor material being responsive to visible panchromatic light, the panchromatic pixel region further comprising a respective panchromatic electrode, the panchromatic electrode comprising one of an anode and a cathode and being operably coupled to a respective source of panchromatic pixel bias voltage;

wherein the nonvisible pixel layer, multicolored pixel layer, and shared electrode layer are constructed and arranged so that, during operation, at least one photodiode formed in the nonvisible pixel layer and multicolored pixel layer is always operating in a photoconducting mode, to enable capture and storage of charge for the photodiode in the device that is operating in photoconducting mode.

18. The multispectral pixel device of claim 12, wherein the multispectral pixel device is configured as part of a back side illumination device.

19. The multispectral pixel device of claim 12, wherein the multispectral pixel device is configured as part of a front side illumination device.

20. A method for capturing an image, the method comprising:

providing a first photodiode having first and second electrodes, the second electrode being operably coupled to a first source of bias voltage at a first potential;

coupling the first electrode to a shared electrode;

operably connecting a second photodiode in series with the first photodiode, the second photodiode being independent of the first photodiode and having third and fourth electrodes, the fourth electrode being operably coupled to a second source of bias voltage at the first potential and the third electrode being coupled to the shared electrode;

operably connecting a third diode in series with the first photodiode, the third photodiode being independent of the first photodiode and comprising fifth and sixth electrodes, the sixth electrode being operably coupled to a third source of bias voltage at the first potential and the fifth electrode being coupled to the shared electrode, wherein the shared electrode is in operable communication with the first, third, and fifth electrodes;

configuring the first photodiode to respond to a first wavelength of light and at least one of the second, and third photodiodes to be responsive to a respective second or third wavelength of light that is shorter than the first wavelength of light;

configuring an electrode node that is in operable communication with the first electrode and the third electrode to be a shared electrode that is configured to operate, respectively, as either a shared anode or a shared cathode for the first, second, and third photodiodes, respectively, wherein the photodiode architecture comprises at least one of a shared anode photodiode architecture and a shared cathode photodiode architecture, wherein the shared electrode node is configured to operate, respectively, as either a shared anode node or a shared cathode node; and

constructing and arranging the first photodiode, second photodiode, third photodiode, and shared electrode to selectively reverse bias the first, second, and/or third photodiodes so that, during operation, at least one of the first, second, and third photodiodes is always operating in a photoconducting mode, to enable capture and storage of charge from any photodiode in the photodiode architecture that is operating in photoconducting mode.