Photoelectric converter

• US 6,069,393 A
• Filed: 06/06/1995
• Issued: 05/30/2000
• Est. Priority Date: 06/26/1987
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Itabashi, Satoshi, Yamada, Katsuhiko, Tashiro, Kazuaki, Saika, Toshihiro, Ishii, Takayuki, Shimada, Tetsuya, Hatanaka, Katsunori
• Primary Examiner(s): Meier, Stephen D.
• Application Number:
  US08/468,518
• Time in Patent Office: 1,820 Days
• Field of Search: 357/30 R, 357/30 G, 357/30 H, 357/30 Q, 357/51, 357/31, 357/23.6, 257/434, 257/435, 257/443
• US Class Current: 257/434
• 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 27/14665 Imagers using a photoconductor layer
• CPC Class Codes: H01L 31/1126 the device being a field-effect phototransistor

Abstract

An image sensor includes a photoelectric conversion unit, a charge storage unit, a switch unit, and a wiring unit, all of which are formed on a single substrate. A capacitor of the charge storage unit is formed at the same substrate position as that of a pattern of said wiring unit.

Claims

1. A photoelectric converter comprising:

a substrate bearing a layered structure comprising in order, a first conductive layer, a first insulating layer, a semiconductor layer, an ohmic contact layer, a second conductive layer, a second insulating layer, and a third conductive layer, said photoelectric converter comprising the following components formed from said layered structure;

a plurality of one-dimensionally arranged photoelectric conversion elements, each photoelectric conversion element including a lower electrode formed from said first conductive layer, said first insulating layer, said semiconductor layer, said ohmic contact layer having a first gap therein, a pair of upper electrodes formed from said second conductive layer and separated by said first gap, and said second insulating layer formed over said first gap;

a plurality of thin-film transistors (TFT), each TFT having a gate electrode formed from said first conductive layer, said first insulating layer, said semiconductor layer, said ohmic contact layer having a second gap therein, and a drain electrode and a source electrode formed from said second conductive layer and separated by said second gap, and said second insulating layer formed over said second gap;

a plurality of output lines formed from said first conductive layer;

a first plurality of through holes formed from said second conductive layer, wherein a respective one of said drain and source electrodes is connected to a respective one of said upper electrodes of said photoelectric conversion device, and the other of said drain and source electrodes is connected to a respective one of said output lines through a respective one of said first plurality of through holes;

a plurality of common lines formed from said third conductive layer, each common line connecting to at least two of said plurality of output lines respectively through a second plurality of through holes formed from said second and third conductive layers, said second conductive layer being further positioned between one of said common lines and one of said output lines at a respective intersection where said one common line overlaps said one output line and capable of being maintained at a first predetermined potential sufficiently high to substantially eliminate stray capacitance at said intersection.

2. A photoelectric converter according to claim 1, further comprising a plurality of capacitors, each capacitor including a lower plate formed from said first conductive layer, said first insulating layer, said semiconductor layer, said ohmic contact layer, and an upper plate formed from said second conductive layer and electrically connected to one of said upper electrodes of said photoelectric conversion element.

3. A photoelectric converter according to claim 1, further comprising a first wiring pattern respectively arranged between pairs of said output lines, said first wiring pattern formed from said first conductive layer, and a second wiring pattern respectively arranged between pairs of said common lines, said second wiring pattern formed from said third conductive layer, said first and second wiring patterns being connected to each other by a third plurality of through holes formed from said second conductive layer and capable of being maintained at a second predetermined potential sufficiently high to eliminate interline capacitance between said output lines, and interline capacitance between said common lines.

4. A photoelectric converter according to claim 1, wherein said TFTs have a channel region, and further comprising a light shield formed from said third conductive layer and positioned over a portion of said second insulating layer covering the channel region of at least one of said TFTs.

5. A photoelectric converter according to claim 1, further comprising an electrostatic shield formed from said third conductive layer and positioned over a portion of said second insulating layer, said electrostatic shield circumferentially covering said pair of upper electrodes of at least one of said photoelectric conversion elements.

6. A photoelectric converter according to claim 1, wherein said TFTs have a channel region, and have a second gate formed from said third conductive layer and positioned over a portion of said second insulating layer covering the channel region of said TFTs.

13. A photoelectric converter according to any of claims 1 or 7, wherein said semiconductor layer comprises an amorphous silicon.

14. A photoelectric converter according to claim 13, wherein said amorphous silicon includes hydrogen.

15. A photoelectric converter according to any of claims 1 or 7, wherein said first insulating layer comprises a silicon nitride.

16. A photoelectric converter according to any of claims 1 or 7, wherein said ohmic contact layer comprises n⁺ amorphous silicon.

17. A photoelectric converter according to claim 16, wherein said n⁺ amorphous silicon includes hydrogen.

7. A photoelectric converter comprising:

a substrate bearing a layered structure comprising in order, a first conductive layer, a first insulating layer, a semiconductor layer, an ohmic contact layer, a second conductive layer, a second insulating layer, and a third conductive layer, said photoelectric converter comprising the following components formed from said layered structure;

a plurality of one-dimensionally arranged photoelectric conversion elements, each photoelectric conversion element including a lower electrode formed from said first conductive layer, said first insulating layer, said semiconductor layer, said ohmic contact layer having a first gap therein, a first upper electrode and a second upper electrode formed from said second conductive layer separated by said first gap, and said second insulating layer formed over said first gap;

a plurality of storage capacitors, each storage capacitor including a lower plate formed from said first conductive layer, said first insulating layer, said semiconductor layer, said ohmic contact layer, and an upper plate formed from said second conductive layer;

a plurality of readout capacitors, each readout capacitor including a lower plate formed from said first conductive layer, said first insulating layer, said semiconductor layer, said ohmic contact layer, and an upper plate formed from said second conductive layer;

a plurality of transfer thin-film transistors (transfer TFTs), each transfer TFT having a gate electrode formed from said first conductive layer, said first insulating layer, said semiconductor layer, said ohmic contact layer having a second gap therein, and a drain electrode and a source electrode formed from said second conductive layer and separated by said second gap, and said second insulating layer formed over said second gap;

a plurality of reset thin-film transistors (reset TFTs), each reset TFT having a gate electrode formed from said first conductive layer, said first insulating layer, said semiconductor layer, said ohmic contact layer having a second gap therein, and a drain electrode and a source electrode formed from said second conductive layer and separated by said second gap, and said second insulating layer formed over said second gap; and

a plurality of signal lines formed from said third conductive layer and connected through a respective first plurality of through holes to respective ones of said source electrodes of said transfer TFTs and to respective ones of said lower plates of said readout capacitors,

and wherein said plurality of signal lines overlie said plurality of storage capacitors, being electrically separated therefrom by said second insulating layer.

8. A photoelectric converter according to claim 7, further comprising a plurality of gate lines formed from said third conductive layer and connected via a second plurality of through holes to respective gate electrodes of said transfer TFTs and said reset TFTs, wherein said plurality of gate lines overlie said plurality of readout capacitors, being electrically separated therefrom by said second insulating layer.

9. A photoelectric converter according to claim 7, further comprising a sensor voltage line formed from said third conductive layer connected through a third plurality of through holes to said first upper electrodes of said photoelectric conversion elements, said second upper electrodes of said photoelectric conversion elements being respectively connected to (1) said lower electrodes of said photoelectric conversion elements, (2) said lower plates of said storage capacitors, (3) said drain electrodes of said reset TFTs and (4) said drain electrodes of said transfer TFTs.

10. A photoelectric converter according to claim 7, further comprising a reset voltage line formed from said third conductive layer, connected through a fourth plurality of through holes to the source electrodes of said reset TFTs.

11. A photoelectric converter according to claim 7, further comprising a first ground line formed from said second conductive layer and connected to said upper plates of said storage capacitors.

12. A photoelectric converter according to claim 7, further comprising a second ground line formed from said third conductive layer and connected via a fifth plurality of through holes to said upper plates of said readout capacitors.

18. A photoelectric converter comprising:

a substrate bearing a layered structure comprising in order, a first conductive layer, a first insulating layer, a semiconductor layer, an ohmic contact layer, a second conductive layer, a second insulating layer, and a third conductive layer, said photoelectric converter comprising the following components formed from said layered structure;

a plurality of one-dimensionally arranged photoelectric conversion elements, each photoelectric conversion element including a lower electrode formed from said first conductive layer, said first insulating layer, said semiconductor layer, said ohmic contact layer having a first gap therein, a pair of upper electrodes formed from said second conductive layer and separated by said first gap, and said second insulating layer formed over said first gap;

a plurality of thin-film transistors (TFT), each TFT having a gate electrode formed from said first conductive layer, said first insulating layer, said semiconductor layer, said ohmic contact layer having a second gap therein, and a drain electrode and a source electrode formed from said second conductive layer and separated by said second gap, and said second insulating layer formed over said second gap;

a plurality of output lines formed from said first conductive layer;

a first plurality of through holes formed from said second conductive layer, wherein a respective one of said drain and source electrodes is connected to a respective one of said upper electrodes of said photoelectric conversion device, and the other of said drain and source electrodes is connected to a respective one of said output lines through a respective one of said first plurality of through holes;

a plurality of common lines formed from said third conductive layer, each common line connecting to at least two of said plurality of output lines respectively through a second plurality of through holes formed from said second and third conductive layers; and

a first wiring pattern respectively arranged between pairs of said output lines, said first wiring pattern formed from said first conductive layer, and a second wiring pattern respectively arranged between pairs of said common lines, said second wiring pattern formed from said third conductive layer, said first and second wiring patterns being connected to each other by a third plurality of through holes formed from said second conductive layer and capable of being maintained at a predetermined potential sufficiently high to eliminate interline capacitance between said output lines, and interline capacitance between said common lines.

19. A photoelectric converter comprising:

a substrate bearing a layered structure comprising in order, a first conductive layer, a first insulating layer, a semiconductor layer, an ohmic contact layer, a second conductive layer, a second insulating layer, and a third conductive layer, said photoelectric converter comprising the following components formed from said layered structure;

a plurality of one-dimensionally arranged photoelectric conversion elements, each photoelectric conversion element including a lower electrode formed from said first conductive layer, said first insulating layer, said semiconductor layer, said ohmic contact layer having a first gap therein, a pair of upper electrodes formed from said second conductive layer and separated by said first gap, and said second insulating layer formed over said first gap;

a plurality of thin-film transistors (TFT), each TFT having a gate electrode formed from said first conductive layer, said first insulating layer, said semiconductor layer, said ohmic contact layer having a second gap therein, and a drain electrode and a source electrode formed from said second conductive layer and separated by said second gap, and said second insulating layer formed over said second gap, each of said TFTs having a channel region;

a first plurality of through holes formed from said second conductive layer, wherein a respective one of said drain and source electrodes is connected to a respective one of said upper electrodes of said photoelectric conversion device; and

a light shield formed from said third conductive layer and positioned over a portion of said second insulating layer covering the channel region of at least one of said TFTs.

20. A photoelectric converter comprising:

a substrate bearing a layered structure comprising in order, a first conductive layer, a first insulating layer, a semiconductor layer, an ohmic contact layer, a second conductive layer, a second insulating layer, and a third conductive layer, said photoelectric converter comprising the following components formed from said layered structure;

a plurality of one-dimensionally arranged photoelectric conversion elements, each photoelectric conversion element including a lower electrode formed from said first conductive layer, said first insulating layer, said semiconductor layer, said ohmic contact layer having a first gap therein, a pair of upper electrodes formed from said second conductive layer and separated by said first gap, and said second insulating layer formed over said first gap; and

an electrostatic shield formed from said third conductive layer and positioned over a portion of said second insulating layer, said electrostatic shield circumferentially covering said pair of upper electrodes of at least one of said photoelectric conversion elements.

21. A photoelectric converter comprising:

a substrate bearing a layered structure comprising in order, a first conductive layer, a first insulating layer, a semiconductor layer, an ohmic contact layer, a second conductive layer, a second insulating layer, and a third conductive layer, said photoelectric converter comprising the following components formed from said layered structure;

a plurality of one-dimensionally arranged photoelectric conversion elements, each photoelectric conversion element including a lower electrode formed from said first conductive layer, said first insulating layer, said semiconductor layer, said ohmic contact layer having a first gap therein, a pair of upper electrodes formed from said second conductive layer and separated by said first gap, and said second insulating layer formed over said first gap;

a plurality of thin-film transistors (TFT), each TFT having a gate electrode formed from said first conductive layer, said first insulating layer, said semiconductor layer, said ohmic contact layer having a second gap therein, and a drain electrode and a source electrode formed from said second conductive layer and separated by said second gap, and said second insulating layer formed over said second gap, each of said TFTs having a channel region and a second gate formed from said third conductive layer and positioned over a portion of said second insulating layer covering the channel region of said TFTs; and

a first plurality of through holes formed from said second conductive layer, wherein a respective one of said drain and source electrodes is connected to a respective one of said upper electrodes of said photoelectric conversion device.