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CN-122002917-A - Avalanche photodiode, photoelectric detection chip and optical communication equipment

CN122002917ACN 122002917 ACN122002917 ACN 122002917ACN-122002917-A

Abstract

The embodiment of the application provides an avalanche photodiode, a photoelectric detection chip and optical communication equipment, relates to the technical field of photoelectric conversion devices, and aims to solve the problem that noise and dark current in a waveguide type avalanche photodiode are large. The avalanche photodiode comprises a first semiconductor layer and a second semiconductor layer, wherein the first semiconductor layer comprises a waveguide part and a device part which are arranged in a first direction, the device part comprises a first ohmic contact region, a first charge region, a first multiplication region, a second charge region and a second ohmic contact region which are arranged in sequence in a second direction perpendicular to the first direction, the first charge region, the second charge region and the first ohmic contact region are P-type doped regions, the second ohmic contact region is an N-type doped region, and the first multiplication region is an intrinsic region. The second semiconductor layer is arranged on one side of the first semiconductor layer and is in contact with the first charge region, and is used for absorbing incident light to generate photo-generated carriers. The avalanche photodiode described above can be applied to optical communication.

Inventors

  • WANG XU
  • CHEN WENJUN
  • SUN WEICHAO
  • CAO HENGZHEN
  • DAI DAOXIN

Assignees

  • 华为技术有限公司

Dates

Publication Date
20260508
Application Date
20241105

Claims (15)

  1. 1. An avalanche photodiode, characterized in that the avalanche photodiode comprises: A first semiconductor layer including a waveguide portion and a device portion arranged in a first direction; the device comprises a waveguide part, a first ohmic contact region, a first charge region, a first multiplication region, a second charge region and a second ohmic contact region, wherein the first ohmic contact region, the first charge region, the second charge region and the first ohmic contact region are all P-type doped regions, the second ohmic contact region is an N-type doped region, and the first multiplication region is an intrinsic region; A second semiconductor layer for generating photo-generated carriers by absorbing incident light, the second semiconductor layer and the first semiconductor layer being stacked in a third direction and covering a portion of the first charge region, wherein the first direction, the second direction, and the third direction are perpendicular to each other, the portion of the first charge region is adjacent to the second ohmic contact region with respect to the second semiconductor layer in the second direction, and A first electrode in contact with the first ohmic contact region and a second electrode in contact with the second ohmic contact region.
  2. 2. The avalanche photodiode according to claim 1 wherein the device portion further comprises a second multiplication region between the second charge region and the second ohmic contact region, the second multiplication region being an intrinsic region.
  3. 3. The avalanche photodiode according to claim 1 or 2 wherein the doping concentrations of the first and second charge regions are the same.
  4. 4. The avalanche photodiode according to any one of claims 1 to 3 wherein between the first multiplication region and the second charge region, the device portion further comprises at least one pair of a third charge region and a third multiplication region; In the second direction, the third charge region is in contact with the third multiplication region, the first charge region being proximate to the first ohmic contact region relative to the third multiplication region.
  5. 5. The avalanche photodiode according to claim 4 wherein doping concentrations of the third charge region, the first charge region and the second charge region are equal.
  6. 6. The avalanche photodiode according to any one of claims 1 to 5 wherein the first semiconductor layer is a ridge waveguide structure extending in the first direction, the second semiconductor layer being disposed on top of ridge protrusions in the ridge waveguide structure.
  7. 7. The avalanche photodiode according to any one of claims 1 to 6 wherein the device portion further comprises an intermediate intrinsic region located between the first charge region and the first ohmic contact region, the second semiconductor layer being in contact with the intermediate intrinsic region.
  8. 8. The avalanche photodiode according to any of claims 1 to 7 wherein the semiconductor material in the first semiconductor layer comprises silicon and the semiconductor material in the second semiconductor layer comprises germanium.
  9. 9. The avalanche photodiode according to any one of claims 1 to 7 wherein the semiconductor material in the first semiconductor layer comprises at least one of indium phosphide, indium aluminum arsenic and gallium arsenide; The material of the first multiplication region comprises at least one of indium phosphide, indium gallium arsenide, indium aluminum arsenide and indium gallium arsenide phosphide; the semiconductor material of the second semiconductor layer includes at least one of InGaAs, inAlAs, and GaAs.
  10. 10. The avalanche photodiode according to any one of claims 1 to 9, wherein a portion of the first charge region that is close to the second ohmic contact region with respect to the second semiconductor layer in the second direction is a first excess portion, a length of the first excess portion in the second direction being a first length; the length of the second charge region in the second direction is a second length; Wherein the first length is 40 nm to 160 nm, and/or the second length is 40 nm to 160 nm.
  11. 11. The avalanche photodiode according to any one of claims 1 to 10 wherein the length of the first multiplication region in the second direction is 50 to 300 nanometers.
  12. 12. The avalanche photodiode according to claim 2 wherein the length of the first multiplication region in the second direction is 50 to 300 nanometers and the length of the second multiplication region in the second direction is 50 to 300 nanometers; The total length of the first multiplication region and the second multiplication region in the second direction is less than or equal to 500 nanometers.
  13. 13. The avalanche photodiode according to any of claims 1 to 12 wherein the first ohmic contact region comprises a first sub-contact region and a second sub-contact region in contact, the first sub-contact region having a higher doping concentration than the second sub-contact region, the second sub-contact region having a higher doping concentration than the first charge region and the second charge region; The first ohmic contact region comprises a third sub-contact region and a fourth sub-contact region which are in contact, the doping concentration of the third sub-contact region is higher than that of the fourth sub-contact region, the doping concentration of the fourth sub-contact region is higher than that of the first charge region and the second charge region, and the second electrode is in contact with the third sub-contact region.
  14. 14. A photodetection chip, characterized in that the photodetection chip comprises: the avalanche photodiode according to any one of claims 1 to 13, and The packaging structure is used for packaging the avalanche photodiode and is provided with an optical port and a bonding pad, wherein the optical port is used for exposing an optical inlet end face of a waveguide part in the avalanche photodiode, and the bonding pad is used for leading out a first electrode and a second electrode in the avalanche photodiode.
  15. 15. An optical communication device, the optical communication device comprising: The photodetection chip according to claim 14, and And the signal processing circuit is electrically connected with the bonding pad in the photoelectric detection chip.

Description

Avalanche photodiode, photoelectric detection chip and optical communication equipment Technical Field The application relates to the technical field of photoelectric conversion devices, in particular to an avalanche photodiode, a photoelectric detection chip and optical communication equipment. Background The avalanche photodiode (AVALANCHE PHOTODIODE, APD) is a photoelectric conversion device based on photoelectric effect and avalanche multiplication effect, and can amplify photoelectric signals by utilizing the avalanche multiplication effect of carriers while realizing photoelectric conversion, so that the avalanche photodiode has higher sensitivity compared with a common photoelectric detection chip, and is favorable for realizing detection of weak optical signals. Avalanche photodiodes also have the advantage of fast response speed, and are widely used in the fields of optical communication, laser ranging, single photon counting and the like. Avalanche photodiodes can be classified into planar, mesa, and waveguide types according to the structure. In the planar and mesa avalanche photodiodes, the absorption direction of light is the same as the movement direction of carriers, resulting in a contradiction between responsivity and bandwidth, i.e., high responsivity and high bandwidth cannot be achieved at the same time. In the waveguide type avalanche photodiode, the light absorption direction is orthogonal to the carrier movement direction, so that decoupling between responsivity and bandwidth is realized, high responsivity and high bandwidth can be realized at the same time, and in particular, the germanium-silicon waveguide type APD is compatible with CMOS (Complementary Metal Oxide Semiconductor ) technology. The waveguide type avalanche photodiode still has the problem of large noise and dark current. Disclosure of Invention The application provides an avalanche photodiode, a photoelectric detection chip and optical communication equipment, which are used for improving the problem of larger noise and dark current in the waveguide type avalanche photodiode. In order to achieve the above purpose, the application adopts the following technical scheme: In a first aspect, an avalanche photodiode is provided that includes a first semiconductor layer, a second semiconductor layer, a first electrode, and a second electrode. The first semiconductor layer includes a waveguide portion and a device portion arranged in a first direction, the waveguide portion being for guiding incident light to the device portion. In a second direction perpendicular to the first direction, the device part comprises a first ohmic contact region, a first charge region, a first multiplication region, a second charge region and a second ohmic contact region which are sequentially arranged, wherein the first charge region, the second charge region and the first ohmic contact region are all P-type doped regions, the second ohmic contact region is an N-type doped region, and the first multiplication region is an intrinsic region. The first electrode is in contact with the first ohmic contact region, and the second electrode is in contact with the second ohmic contact region. The second semiconductor layer is used for absorbing incident light to generate photo-generated carriers, and the second semiconductor layer and the first semiconductor layer are stacked in a third direction and cover a part in the first charge region, wherein the first direction, the second direction and the third direction are perpendicular to each other. In the second direction, a portion of the first charge region is adjacent to the second ohmic contact region with respect to the second semiconductor layer. The avalanche photodiode provided by the application is a waveguide type avalanche photodiode, and adopts a design of transverse separation absorption charge multiplication (Separate Absorption CHARGE AND Multiplication, SACM), in this case, the direction of incident light entering the avalanche photodiode is parallel to a first direction, the movement direction of carriers in the avalanche photodiode is parallel to a second direction, and the first direction and the second direction are perpendicular. That is, the light absorption direction is orthogonal to the carrier movement direction, so that decoupling of the problems of responsivity and bandwidth can be achieved, which is advantageous for achieving both high responsivity and high bandwidth. In the avalanche photodiode provided by the application, a first charge region, a first multiplication region and a second charge region are included between a first ohmic contact region and a second ohmic contact region. The second charge region is a P-type doped region, and the second ohmic contact region is an N-type doped region. The second charge region and the second ohmic contact region are directly contacted to form a PN junction, and the PN junction can form a depletion region at the contact position of t