Solid-state image pickup element and image pickup apparatus

Patent metadata

Field	Value
Publication number	US-11483507-B2
Application number	US-201916490339-A
Country	US
Kind code	B2
Filing date	Mar 13, 2019
Priority date	May 2, 2018
Publication date	Oct 25, 2022
Grant date	Oct 25, 2022

Abstract

There is provided a solid-state image pickup element including: a photodiode configured to convert incident light into a photocurrent; an amplification transistor configured to amplify a voltage between a gate having a potential depending on the photocurrent and a source having a predetermined reference potential and output the amplified voltage from a drain; and a potential supply section configured to supply an anode of the photodiode and a back-gate of the amplification transistor with a predetermined potential lower than the reference potential.

First claim

The invention claimed is:

1. A solid-state image pickup element, comprising:
a first substrate;
a second substrate laminated in a stacked arrangement with the first substrate;
a photodiode arranged in the first substrate and configured to convert incident light into a photocurrent;
an amplification transistor arranged in the first substrate and including a gate, a source and a drain, the source is connected to a predetermined reference potential, the amplification transistor is configured to amplify a voltage between the gate being connected to a potential depending on the photocurrent and the source being connected to the predetermined reference potential, and is configured to output the amplified voltage to the drain;
a potential supply section configured to supply an anode of the photodiode and a back-gate of the amplification transistor with a same predetermined potential lower than the predetermined reference potential;
a buffer circuit connected to the amplification transistor and arranged in the second substrate; and
a quantizer arranged in the second substrate.

2. The solid-state image pickup element according to claim 1 , further comprising
a conversion transistor configured to convert the photocurrent into a voltage between a gate and a source, wherein
the conversion transistor includes a source which is connected to a cathode of the photodiode and the gate of the amplification transistor, and
the drain of the amplification transistor is directly electrically connected to the gate of the conversion transistor.

3. The solid-state image pickup element according to claim 2 , wherein
the photodiode and the amplification transistor are arranged in each of an effective pixel in which light is not shielded and a light-shielding pixel in which light is shielded, and
the potential supply section supplies the anode of the photodiode corresponding to the effective pixel with the same predetermined potential and supplies the anode of the photodiode corresponding to the light-shielding pixel with the predetermined reference potential.

4. The solid-state image pickup element according to claim 2 , wherein
the conversion transistor is arranged in the first substrate.

5. The solid-state image pickup element according to claim 4 , further comprising
a subtractor configured to lower a level of the voltage signal from the buffer; and
a comparator configured to compare the lowered voltage signal with a predetermined threshold.

6. The solid-state image pickup element according to claim 5 , wherein
the conversion transistor and the amplification transistor are arranged in a current-to-voltage conversion circuit configured to convert the photocurrent into the voltage signal, and
the current-to-voltage conversion circuit has a power supply voltage different from a power supply voltage of the buffer, the subtractor, and the comparator.

7. The solid-state image pickup element according to claim 5 , wherein
the subtractor and the comparator include at least a part arranged in the second substrate.

8. An image pickup apparatus, comprising:
a first substrate;
a second substrate laminated in a stacked arrangement with the first substrate;
a photodiode arranged in the first substrate and configured to convert incident light into a photocurrent;
an amplification transistor arranged in the first substrate and including a gate, a source and a drain, the source is connected to a predetermined reference potential, the amplification transistor is configured to amplify a voltage between the gate being connected to a potential depending on the photocurrent and the source being connected to the predetermined reference potential, and is configured to output the amplified voltage to the drain;
a potential supply section configured to supply an anode of the photodiode and a back-gate of the amplification transistor with a same predetermined potential lower than the predetermined reference potential;
a buffer circuit connected to the amplification transistor and arranged in the second substrate; and
a quantizer arranged in the second substrate; and
a signal processing circuit configured to process a signal output from the amplification transistor.

9. The image pickup apparatus according to claim 8 , further comprising
a conversion transistor configured to convert the photocurrent into a voltage between a gate and a source, wherein
the conversion transistor includes a source which is connected to a cathode of the photodiode and the gate of the amplification transistor, and
the drain of the amplification transistor is directly electrically connected to the gate of the conversion transistor.

10. The image pickup apparatus according to claim 9 , wherein
the photodiode and the amplification transistor are arranged in each of an effective pixel in which light is not shielded and a light-shielding pixel in which light is shielded, and
the potential supply section supplies the anode of the photodiode corresponding to the effective pixel with the same predetermined potential and supplies the anode of the photodiode corresponding to the light-shielding pixel with the predetermined reference potential.

11. The image pickup apparatus according to claim 9 , wherein
the conversion transistor is arranged in the first substrate.

12. The image pickup apparatus according to claim 11 , further comprising
a subtractor configured to lower a level of the voltage signal from the buffer; and
a comparator configured to compare the lowered voltage signal with a predetermined threshold.

13. The image pickup apparatus according to claim 12 , wherein
the conversion transistor and the amplification transistor are arranged in a current-to-voltage conversion circuit configured to convert the photocurrent into the voltage signal, and
the current-to-voltage conversion circuit has a power supply voltage different from a power supply voltage of the buffer, the subtractor, and the comparator.

14. The image pickup apparatus according to claim 12 , wherein
the subtractor and the comparator include at least a part arranged in the second substrate.

15. The solid-state image pickup element according to claim 1 , wherein the source of the amplification transistor is directly electrically connected to the predetermined reference potential.

16. The image pickup apparatus according to claim 8 , wherein the source of the amplification transistor is directly electrically connected to the predetermined reference potential.

Assignees

• Sony Semiconductor Solutions Corp
• Sony Semiconductor Solution Corp

Inventors

• Niwa Atsumi

Classifications

• H04N25/77

  Pixel circuitry, e.g. memories, A/D converters, pixel amplifiers, shared circuits or shared components · CPC title

• H04N25/709

  Circuitry for control of the power supply · CPC title

• H04N25/75 Primary

  Circuitry for providing, modifying or processing image signals from the pixel array · CPC title

• H04N25/79

  Arrangements of circuitry being divided between different or multiple substrates, chips or circuit boards, e.g. stacked image sensors · CPC title

• H04N5/3745

  Electricity · mapped topic