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EP0076143A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Avalanche photodiode

Assignee: Fujitsu Ltd
•
Filing: 1982-09-28
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Granted: —
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Expires: 2002-09-28
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Abstract

Abstract A practical germanium avalanche photodiode (Ge APD) for use with 1.5 mu m band light with which a silica optical fibre has a minimum transmission loss is provided by forming a reach-through type Ge APD having a P<+>NN<-> structure. Typically the photodiode includes an N<-> type substrate 1 with a P<+> type region 2 in the substrate and adjacent its surface with an N type region 3 interposed between the P<+> type region 2 and the N<-> type region 1. Preferably the P<+> type region 2 and the N type region 3 are surrounded by a P type region 4 forming a guard ring. It is further preferred that the doping concentration of the N<-> type region 1 is below 1 x 10<1><5> cm<-><3> and the doping of the N type region 3 is between 1 x 10<1><6> and 1 x 10<1><7> cm<-><3>.

Inventors

  • 👤 Takashi Mikawa
  • 👤 Shuzo Kagawa
  • 👤 Katsuji Honma
  • 👤 Takao Kaneda

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-07 06:47
CPC Classifications
H; H10; H10F; H10F30/00; H10F30/20; H10F30/21; H10F30/22; H10F30/225

Claims Analysis

Total Claims: 7
Claim 1
Independent Claim 55 words
An avalanche photodiode comprising a germanium semiconductor substrate comprising an N - type region (1); a P + type region (2) in the substrate and adjacent the surface of the substrate; and an N type region (3) in the substrate interposed between the P + type region (2) and the N - type region (1).
Claim 2
Dependent Claim 55 words
An avalanche photodiode comprising a germanium semiconductor substrate comprising an N - type region (1); a P + type region (2) in the substrate and adjacent the surface of the substrate; and an N type region (3) in the substrate interposed between the P + type region (2) and the N - type region (1).
Claim 3
Dependent Claim 19 words
An avalanche photodiode according to claim 1, wherein the N type region (3) is doped with arsenic or phosphorus.
Claim 4
Dependent Claim 31 words
An avalanche photodiode according to claim 1 or 2, wherein the N - type region (1) has a concentration of N type impurity below 1 x 10 15 cm 3 .
Claim 5
Dependent Claim 105 words
An avalanche photodiode according to claim 2 or 3, wherein the N type region (3) doped with arsenic or phosphorus has in a direction from its one side adjacent the P + type region (2) towards its other side adjacent the N - type region an approximate Gaussian distribution of the arsenic or phosphorus concentration, the width of the distribution being between about 1.5 µm to 2.5 µm and the concentration of the arsenic or phosphorus at its side adjacent the the P + type region being at maximum between about 1 x 10 16 cm -3 and 1 x 10 17 cm -3 .
Claim 6
Dependent Claim 65 words
An avalanche photodiode according to claim 1, wherein the N type region has a concentration of an N type impurity below 1 x 10 15 cm -3 and the N type region is formed by implanting arsenic ions into the germanium semiconductor substrate in a dose in the range of from 5 x 10 12 cm -2 to 1 x 10 13 cm -2 .
Claim 7
Dependent Claim 37 words
An avalanche photodiode according to any one of the preceding claims, in which the P + type region (2) and the N type region (3) are surrounded by a P type region (4) forming a guard ring.

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