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CN-122002939-A - Light detecting element

CN122002939ACN 122002939 ACN122002939 ACN 122002939ACN-122002939-A

Abstract

The light detection element of the present invention includes a first semiconductor layer having a first main surface and a second main surface as light incidence surfaces. The first semiconductor layer has a plurality of first semiconductor regions of a first conductivity type, a plurality of second semiconductor regions of a second conductivity type constituting a plurality of avalanche photodiodes together with the plurality of first semiconductor regions, and a frame region of the first conductivity type formed in a frame shape so as to surround the plurality of avalanche photodiodes. A trench is formed in the first semiconductor layer. The trench includes a plurality of frame portions that extend so as to surround the corresponding avalanche photodiodes, respectively. The impurity concentration of the frame region is higher than that of the plurality of first semiconductor regions. The width of the frame region is greater than the width of the region surrounded by the frame portion.

Inventors

  • Gang Tian Zhensheng
  • SHI YOUTAI
  • Earth house Okiayu Ryotaro
  • Rock entry

Assignees

  • 浜松光子学株式会社

Dates

Publication Date
20260508
Application Date
20251104
Priority Date
20241105

Claims (6)

  1. 1. A light detecting element, wherein, The device is provided with: A first semiconductor layer having a first main surface as a light incident surface and a second main surface opposite to the first main surface, and A plurality of quenching elements located on the second main surface side with respect to the first semiconductor layer, The first semiconductor layer has: A plurality of first semiconductor regions of a first conductivity type; a plurality of second semiconductor regions of a second conductivity type located closer to the second main surface than the plurality of first semiconductor regions, and forming a plurality of avalanche photodiodes together with the plurality of first semiconductor regions; A plurality of third semiconductor regions of the first conductivity type located closer to the first main surface than the plurality of first semiconductor regions and having an impurity concentration higher than that of the plurality of first semiconductor regions, and A frame region of the first conductivity type formed in a frame shape so as to surround the plurality of avalanche photodiodes when viewed from a direction perpendicular to the first main surface, and electrically connected to the first semiconductor region, Each of the plurality of quenching elements is electrically connected to a corresponding one of the plurality of second semiconductor regions, A trench extending so as to separate the plurality of avalanche photodiodes from each other is formed in the first semiconductor layer, The trench includes a plurality of frame portions extending so as to surround the corresponding avalanche photodiodes of the plurality of avalanche photodiodes, respectively, when viewed from a direction perpendicular to the first main surface, The frame region has an impurity concentration higher than that of the plurality of first semiconductor regions, The frame region has a width, as viewed from a direction perpendicular to the first main surface, that is greater than a width of each of a plurality of regions surrounded by the plurality of frame portions in the first semiconductor layer.
  2. 2. The light detecting element as in claim 1, wherein, The width of the frame region is 2 times or more the width of the region surrounded by each of the plurality of frame portions when viewed from a direction perpendicular to the first main surface.
  3. 3. The light detecting element according to claim 1 or 2, wherein, The frame region has a width, when viewed from a direction perpendicular to the first main surface, that is greater than a width of a region located between the frame region and the plurality of frame portions.
  4. 4. The photodetection element according to any one of claims 1 to 3, wherein, Further comprises a metal wiring formed on the first main surface, The trench is formed in such a manner as to separate the plurality of third semiconductor regions from each other and reach the second main surface from the first main surface, The metal wiring electrically connects the plurality of third semiconductor regions to each other.
  5. 5. The light detecting element as in claim 4, wherein, The first semiconductor layer further includes a fourth semiconductor region of the first conductivity type located closer to the first main surface than the frame region, having an impurity concentration higher than that of the plurality of first semiconductor regions, The fourth semiconductor region is formed in a frame shape so as to surround the plurality of frame portions when viewed from a direction perpendicular to the first main surface, The metal wiring electrically connects the fourth semiconductor region and the plurality of third semiconductor regions to each other.
  6. 6. The light detecting element as in claim 5, wherein, The frame region is formed so as to reach the fourth semiconductor region from the second main surface in a direction perpendicular to the first main surface.

Description

Light detecting element Technical Field One aspect of the present disclosure relates to a light detecting element. Background International publication No. 2018/174090 discloses an imaging device as an example of a light detection element, which includes a first semiconductor layer formed on a semiconductor substrate, a second semiconductor layer formed on the first semiconductor layer and having a conductivity type opposite to that of the first semiconductor layer, a third semiconductor layer formed on the second semiconductor layer and having a conductivity type identical to that of the second semiconductor layer, a pixel isolation portion defining a pixel region including the first semiconductor layer and the second semiconductor layer, a first electrode connected to the first semiconductor layer, and a second electrode connected to the second semiconductor layer. In such a light detection element, light incident on each pixel region is photoelectrically converted and detected as a current signal. For example, in the imaging device described in international publication No. 2018/174090, after charge carriers are generated (photoelectrically converted) in the third semiconductor layer by incidence of light, the charge carriers are multiplied in the first semiconductor layer and the second semiconductor layer after voltage is applied thereto via the first electrode and the second electrode. The multiplied charge carriers are detected as a current signal. Disclosure of Invention Problems to be solved by the invention In the above-described photodetecting element, for example, a voltage is applied to the first electrode and the second electrode from a power supply circuit formed in a circuit layer of the semiconductor substrate. For example, when the first electrode is disposed in the vicinity of some of the plurality of pixels and is disposed away from the other pixels, among the first electrode and the second electrode connected to the power supply circuit, a voltage value applied to the pixel positioned away from the first electrode becomes relatively small, and a potential gradient is generated between the pixels. This potential gradient produces a deviation in the current signal between pixels. When a voltage is applied from the power supply circuit to the first electrode and the second electrode via the wiring, a voltage drop and heat generation occur due to wiring resistance. Such voltage drop and heat generation cause a decrease in the current signal generated in the pixel. The deviation and decrease of the current signal reduce the detection accuracy. An object of an aspect of the present disclosure is to provide a light detection element capable of suppressing a decrease in detection accuracy. Technical scheme for solving problems The photodetection element according to one aspect of the present disclosure is [1] "a photodetection element comprising a first semiconductor layer having a first main surface as a light incidence surface and a second main surface opposite to the first main surface, and a plurality of quenching elements located on the second main surface side with respect to the first semiconductor layer, the first semiconductor layer comprising a plurality of first semiconductor regions of a first conductivity type, a plurality of second semiconductor regions of a second conductivity type located in the vicinity of the second main surface more than the plurality of first semiconductor regions, forming a plurality of avalanche photodiodes together with the plurality of first semiconductor regions, the plurality of third semiconductor regions of the first conductivity type located in the vicinity of the first main surface more than the plurality of first semiconductor regions, having an impurity concentration higher than that of the plurality of first semiconductor regions, and a frame region of the first conductivity type surrounding the plurality of avalanche photodiodes in a direction perpendicular to the first main surface, the avalanche semiconductor regions extending in a direction perpendicular to the first semiconductor frame, the avalanche semiconductor regions extending in a direction from the plurality of the first semiconductor frame, the plurality of semiconductor regions extending in a direction perpendicular to the first semiconductor frame, the plurality of semiconductor regions extending in a direction from the first semiconductor frame, the plurality of semiconductor regions extending in a direction perpendicular to the semiconductor frame, the plurality of semiconductor regions extending in the semiconductor frame, the frame region has a width, when viewed from a direction perpendicular to the first main surface, that is greater than a width of each of a plurality of regions surrounded by the plurality of frame portions in the first semiconductor layer. In the photodetector, a frame region of the first conductivity type electrically connected to the first semiconductor