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CN-122002937-A - Light detecting element

CN122002937ACN 122002937 ACN122002937 ACN 122002937ACN-122002937-A

Abstract

A light detection element includes 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, a layer structure formed on the first main surface, a metal wiring inside the layer structure, and a plurality of quenching elements. 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 which constitute a plurality of avalanche photodiodes together with the plurality of first semiconductor regions, and a plurality of third semiconductor regions of the first conductivity type which have an impurity concentration higher than that of the plurality of first semiconductor regions. The thickness of the metal wiring is greater than the distance from the first surface of the metal wiring on the opposite side from the first main surface to the surface of the layer structure on the opposite side from the first main surface, and is greater than the distance from the second surface of the metal wiring on the first main surface side to the surface of the layer structure on the first main surface side.

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 (9)

  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; A layer structure formed on the first main surface; a metal wiring formed on the first main surface and having at least a part thereof located inside the layer structure, 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 the second conductivity type located closer to the second main surface than the plurality of first semiconductor regions, together with the plurality of first semiconductor regions, a plurality of avalanche photodiodes, and A plurality of third semiconductor regions of the first conductivity type, which are located closer to the first main surface than the plurality of first semiconductor regions, have an impurity concentration higher than that of the plurality of first semiconductor regions, Each of the plurality of quenching elements is electrically connected to a corresponding one of the plurality of second semiconductor regions, Forming a trench extending so as to separate the plurality of third semiconductor regions from each other in the first semiconductor layer, The metal wiring is formed on the first main surface in such a manner as to extend along the trench, and electrically connects the plurality of third semiconductor regions to each other, The thickness of the metal wiring is larger than the distance from a first surface of the metal wiring opposite to the first main surface to a surface of the layer structure opposite to the first main surface, and is larger than the distance from a second surface of the metal wiring opposite to the first main surface to a surface of the layer structure opposite to the first main surface.
  2. 2. The light detecting element as in claim 1, wherein, The layer structure has a first insulating layer formed on the first main surface and a second insulating layer formed on the first insulating layer, The metal wiring is located inside the first insulating layer and the second insulating layer.
  3. 3. The light detecting element according to claim 2, wherein, The side surface of the metal wiring is in contact with the first insulating layer and the second insulating layer.
  4. 4. The light detecting element as in claim 1, wherein, The layer structure is a single insulating layer.
  5. 5. The photodetection element according to any one of claims 1 to 4, wherein, The lens unit is disposed on the layered structure.
  6. 6. The light detecting element as in claim 5, wherein, The thickness of the metal wiring is larger than a distance from the first main surface side surface to the first surface in the lens portion.
  7. 7. The light detecting element according to claim 5 or 6, wherein, Also comprises a plurality of lens parts which are respectively used as the lens parts, Each of the plurality of lens portions is arranged so as to overlap with a corresponding avalanche photodiode of the plurality of avalanche photodiodes in a direction perpendicular to the first main surface, When viewed from a direction perpendicular to the first main surface, the outer edges of the plurality of lens portions overlap the grooves.
  8. 8. The photodetection element according to any one of claims 1 to 4, wherein, The metal wiring is formed so as to cover the entire trench when viewed from a direction perpendicular to the first main surface, Each of the plurality of avalanche photodiodes is surrounded by the metal wiring when viewed from a direction perpendicular to the first main surface.
  9. 9. 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; A layer structure having a first insulating layer formed on the first main surface and a second insulating layer formed on the first insulating layer; a metal wiring formed on the first main surface and having at least a part thereof located inside the layer structure, 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 the second conductivity type located closer to the second main surface than the plurality of first semiconductor regions, together with the plurality of first semiconductor regions, a plurality of avalanche photodiodes, and A plurality of third semiconductor regions of the first conductivity type, which are located closer to the first main surface than the plurality of first semiconductor regions, have an impurity concentration higher than that of the plurality of first semiconductor regions, Each of the plurality of quenching elements is electrically connected to a corresponding one of the plurality of second semiconductor regions, Forming a trench extending so as to separate the plurality of third semiconductor regions from each other in the first semiconductor layer, The metal wiring is formed on the first main surface in such a manner as to extend along the trench, and electrically connects the plurality of third semiconductor regions to each other, In a direction perpendicular to the first main surface, a surface of the metal wiring on an opposite side to the first main surface is located farther from the first main surface than a surface of the first insulating layer on an opposite side to the first semiconductor layer.

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 photodetector described above, an avalanche photodiode is formed in each pixel, and charge carriers generated in the semiconductor layer by incidence of light are multiplied by the avalanche photodiode and detected. However, the charge carriers multiplied by the avalanche photodiode recombine, sometimes generating secondary photons. Secondary photons may become a major cause of crosstalk. In particular, secondary photons may be incident on other pixels to create new charge carriers. This crosstalk reduces the detection accuracy in the light detecting element. 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 light detection element according to one aspect of the present disclosure is [1] "a light detection element including 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; the semiconductor device includes a first semiconductor region having a first conductivity type, a second semiconductor region having a second conductivity type, a metal wire formed on the first main surface, at least a part of the metal wire being located inside the layer structure, and a plurality of quenching elements located on the second main surface side with respect to the first semiconductor region, the plurality of quenching elements each being electrically connected to a corresponding one of the plurality of second semiconductor regions, a plurality of avalanche photodiodes being formed in the vicinity of the second main surface with respect to the plurality of first semiconductor regions, the plurality of avalanche photodiodes being formed with the plurality of first semiconductor regions, and a plurality of third semiconductor regions of the first conductivity type being located in the vicinity of the first main surface with respect to the plurality of first semiconductor regions, the plurality of quenching elements each being electrically connected to a corresponding one of the plurality of second semiconductor regions, the plurality of semiconductor regions being formed with a trench, the plurality of semiconductor wires being electrically connected to each other by extending the plurality of semiconductor wires from the first main surface to the first main surface by a distance greater than the first semiconductor wire, the plurality of semiconductor wires being formed with a distance greater than the first main surface of the first semiconductor wire, is larger than a distance from the second surface on the first principal surface side in the metal wiring to the surface on the first principal surface side in the layer structure. In the light detecting element, a trench extending so as to separate a plurality of third semiconductor regions from each other is formed on the first semiconductor layer. Thus, the second photons of the charge carriers multiplied by the avalanche photodiode can be prevented from entering the adjacent avalanche photodiode through the third semiconductor region by the trench. The light detection element includes a metal wiring formed on the first main surface so as to extend along the trench, at least a part of the metal wiring being located inside the layer structure, and the thickness of the metal wiring is greater than the distance from the first