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CN-121986498-A - Light detection device

CN121986498ACN 121986498 ACN121986498 ACN 121986498ACN-121986498-A

Abstract

The present invention provides a light detection device that enables improved performance. The light detection device includes a semiconductor substrate having an incident surface on which light from the outside is incident, and a first unit pixel for phase difference detection provided to the semiconductor substrate. The first unit pixels for phase detection each have a first pixel including a first photoelectric conversion portion and a second pixel including a second photoelectric conversion portion having a light receiving area smaller than the first photoelectric conversion portion.

Inventors

  • SHIRAI YUKI

Assignees

  • 索尼半导体解决方案公司

Dates

Publication Date
20260505
Application Date
20241009
Priority Date
20231031

Claims (16)

  1. 1. A light detection device includes a semiconductor substrate having an incidence surface on which external light is incident, and a first unit pixel for phase difference detection provided in the semiconductor substrate, wherein the first unit pixel includes a first pixel provided with a first photoelectric conversion portion and a second pixel provided with a second photoelectric conversion portion having a light receiving area smaller than the first photoelectric conversion portion.
  2. 2. The light detection device according to claim 1, wherein the first unit pixel includes a light shielding film provided on the incidence surface side of the semiconductor substrate, and the light shielding film covers a part of the first photoelectric conversion portion.
  3. 3. The light detection device according to claim 1, wherein the first unit pixel includes a light shielding film provided on the incidence surface side of the semiconductor substrate, and the light shielding film covers a part of the second photoelectric conversion portion.
  4. 4. The light detection device according to claim 1, wherein the first unit pixel includes a light shielding film provided on the incidence surface side of the semiconductor substrate, and the light shielding film covers a portion of the first photoelectric conversion portion and a portion of the second photoelectric conversion portion.
  5. 5. The light detection device according to claim 4, wherein the first pixel includes a first light shielding region covered with the light shielding film and a first opening region uncovered by the light shielding film, the second pixel includes a second light shielding region covered with the light shielding film and a second opening region uncovered by the light shielding film, and the first light shielding region and the second light shielding region are adjacent to each other or the first opening region and the second opening region are adjacent to each other.
  6. 6. The light detection device according to claim 1, further comprising a second unit pixel provided in the semiconductor substrate for image capturing, wherein the first pixel and the second pixel are spaced apart from each other by the second unit pixel.
  7. 7. The light detection device according to claim 1, wherein the first pixel includes a first lens provided on the incidence plane side of the semiconductor substrate and facing the first photoelectric conversion portion, and the second pixel includes a second lens provided on the incidence plane side of the semiconductor substrate and facing the first photoelectric conversion portion.
  8. 8. The light detection device according to claim 1, wherein the first pixel has an L-shape in a plan view from a direction orthogonal to the incident surface of the semiconductor substrate, the second pixel has a quadrangular shape in the plan view, and a shape formed by combining the first pixel and the second pixel is a quadrangle in the plan view.
  9. 9. The light detection device according to claim 8, wherein the first pixel includes a first lens provided on the incidence plane side of the semiconductor substrate and facing the first photoelectric conversion portion, the second pixel includes a second lens provided on the incidence plane side of the semiconductor substrate and facing the first photoelectric conversion portion, and the first lens includes a plurality of lenses arranged along the L shape.
  10. 10. The light detection device according to claim 1, wherein the first pixel further includes a first lens provided on the incident surface side of the semiconductor substrate, the first photoelectric conversion portion includes a first photodiode, and a second photodiode is arranged at a position adjacent to the first photodiode in a direction parallel to the incident surface, and the first lens is arranged as a single lens at a position facing both the first photodiode and the second photodiode.
  11. 11. The light detection device according to claim 1, wherein the first unit pixel further includes a second lens provided on the incidence surface side of the semiconductor substrate, the second pixel includes a third photodiode and a fourth photodiode as the second photoelectric conversion portion, the fourth photodiode is arranged at a position adjacent to the third photodiode in a direction parallel to the incidence surface, and the second lens is arranged as a single lens at a position facing both the third photodiode and the fourth photodiode.
  12. 12. The light detection device according to claim 1, wherein the first unit pixel further includes a first lens provided on the incident surface side of the semiconductor substrate, and a second lens provided on the incident surface side, the first pixel includes a first photodiode and a second photodiode as a first photoelectric conversion portion, the second photodiode is arranged at a position adjacent to the first photodiode in a direction parallel to the incident surface, the first lens is arranged as a single lens at a position facing both the first photodiode and the second photodiode, the second pixel includes a third photodiode and a fourth photodiode as a second photoelectric conversion portion, the fourth photodiode is arranged at a position adjacent to the third photodiode in a direction parallel to the incident surface, and the second lens is arranged as a single lens at a position facing both the third photodiode and the fourth photodiode.
  13. 13. The light detection device according to claim 1, wherein the first unit pixel further includes an inter-pixel isolation portion provided in the semiconductor substrate to provide isolation between the first pixel and the second pixel.
  14. 14. The light detecting device according to claim 13, wherein the inter-pixel isolation portion includes a trench penetrating the semiconductor substrate, and an insulating film buried in the trench.
  15. 15. The light detection device according to claim 2, wherein a pair of the first unit pixels is provided, and the light shielding films of the pair of the first unit pixels are symmetrically arranged in a plan view from a direction orthogonal to the incident surface of the semiconductor substrate.
  16. 16. The light detection device according to claim 15, further comprising a second unit pixel for image capturing provided in the semiconductor substrate, wherein the second unit pixel for image capturing is arranged between one and the other of the pair of first unit pixels.

Description

Light detection device Technical Field The present disclosure relates to a light detection device. Background As a solid-state imaging element, a technique is known in which a structure for detecting a phase difference is provided in a pixel to improve autofocus performance. For example, patent document 1 discloses a structure in which a photodiode is divided into two parts, and two pixels are provided on the same lens on the same chip. Further, patent document 2 also discloses a structure in which a pixel has a light shielding region. With these structures, the phase difference is detected by differentiating the incident light state in the horizontal and vertical directions, so that the in-focus state can be determined. List of citations Patent document Patent document 1 Japanese patent application laid-open No. 2015-225311 Patent document 2 Japanese patent application laid-open No. 2012-173492 Disclosure of Invention Problems to be solved by the invention In order to perform phase difference detection in a high illuminance region, it is necessary for the image pickup apparatuses having the structures disclosed in patent documents 1 and 2 to shorten the charge accumulation time to prevent charge saturation. When the accumulation time is shortened, flickering (i.e., a phenomenon in which brightness changes due to flickering illumination occur in an image) may easily occur due to a periodic light source such as an LED, which may cause degradation in image capturing performance. The present disclosure has been made in view of such circumstances, and an object thereof is to provide a light detection device capable of improving performance. Solution to the problem According to one aspect of the present invention, a light detection device includes a semiconductor substrate having an incident surface on which external light is incident, and a first unit pixel for phase difference detection provided in the semiconductor substrate. The first unit pixel includes a first pixel provided with a first photoelectric conversion portion and a second pixel provided with a second photoelectric conversion portion having a smaller light receiving area than the first photoelectric conversion portion. With this configuration, in the unit pixel for phase difference detection, at least one of the first pixel or the second pixel may be equipped with a phase difference detection function. In performing phase difference detection, a signal may be supplemented between the first pixel and the second pixel. Further, in performing phase difference detection, the first pixel and the second pixel having different sensitivities may be selectively used according to an illuminance region. Therefore, the imaging performance can be improved. Drawings Fig. 1 is a diagram showing a configuration example of an image pickup apparatus according to a first embodiment of the present disclosure. Fig. 2 is a diagram showing an example of a circuit configuration of unit pixels arranged in the pixel array section shown in fig. 1. Fig. 3 is a timing chart for explaining an operation of the unit pixel shown in fig. 2 during readout. Fig. 4 is a plan view showing a configuration example of a unit pixel of the image pickup apparatus according to the first embodiment of the present disclosure. Fig. 5 is a cross-sectional view of the unit pixel shown in fig. 4 taken along a line A-A' parallel to the X-axis direction. Fig. 6 is a cross-sectional view of the unit pixel shown in fig. 4 taken along a line B-B' parallel to a direction in which large pixels and small pixels are arranged. Fig. 7 is a graph showing normal output signals output from large pixels of unit pixels for image capturing and light-shielding output signals 1 and 2 output from large pixels 150 of each of a pair of unit pixels for phase difference detection. Fig. 8 is a plan view schematically showing supplementing of output information using small pixels among unit pixels for phase difference detection according to the first embodiment of the present disclosure. Fig. 9 is a diagram schematically showing that adjacent pixels 500A are used to supplement output information in a pixel for phase difference detection according to a comparative example of the present disclosure. Fig. 10 is a plan view showing a first modification of the unit pixel for phase difference detection according to the first embodiment of the present disclosure. Fig. 11 is a plan view showing a second modification of the unit pixel for phase difference detection according to the first embodiment of the present disclosure. Fig. 12 is a plan view showing a configuration example of an image pickup apparatus according to a second embodiment of the present disclosure. Fig. 13 is a plan view showing a modification of the unit pixel for phase difference detection according to the second embodiment of the present disclosure. Fig. 14A is a plan view showing a configuration example of a unit pixel for phase difference detection of the im