Semiconductor optical element

Patent metadata

Field	Value
Publication number	US-9269869-B2
Application number	US-201114364074-A
Country	US
Kind code	B2
Filing date	Dec 12, 2011
Priority date	Dec 12, 2011
Publication date	Feb 23, 2016
Grant date	Feb 23, 2016

Abstract

In order to provide a highly reliable silicon-germanium semiconductor optical element of high luminous efficiency or of low power consumption that can reduce or prevent the occurrence of dislocations or crystal defects on the interface between a light emitting layer or a light absorption layer and a cladding layer, in a silicon-germanium semiconductor optical element, a germanium protective layer 11 of non-light emission is disposed between a germanium light emitting layer or the light absorption layer 10 and a cladding layer 12 disposed above a substrate. The germanium protective layer 11 has the electrical conductivity different from electrical conductivity of the germanium light emitting layer or the light absorption layer 10.

First claim

The invention claimed is:

1. A semiconductor optical element comprising:
a semiconductor substrate;
a germanium light emitting layer or a germanium light absorption layer formed on the substrate; and
an insulating film formed on the substrate,
wherein the semiconductor optical element includes a structure in which:
a germanium protective layer whose electrical conductivity is different from electrical conductivity of the light emitting layer or the light absorption layer is disposed above the light emitting layer or the light absorption layer;
a cladding layer whose electrical conductivity is the same as electrical conductivity of the protective layer is formed above the germanium protective layer; and
an insulating layer is disposed on both side surfaces of the light emitting layer or the light absorption layer.

2. The semiconductor optical element according to claim 1 , wherein the cladding layer includes the same constituent element as a constituent element of the germanium protective layer.

3. The semiconductor optical element according to claim 1 , wherein the cladding layer includes Si 1-x Ge x (0≦x≦1).

4. The semiconductor optical element according to claim 1 , wherein the cladding layer includes a structure in which germanium composition Si 1-x Ge x (0≦x≦1) is changed step by step or continuously in the layer.

5. The semiconductor optical element according to claim 1 , wherein the protective layer includes a structure in which germanium composition Si 1-x Ge x (0≦x≦1) is changed step by step or continuously in the layer and Ge is rich at the germanium light emitting layer side.

6. The semiconductor optical element according to claim 1 ,
wherein a conductive type of the germanium light emitting layer or the light absorption layer is n-type; and
a conductive type of the protective layer is p-type.

7. The semiconductor optical element according to claim 1 , wherein the light emitting layer includes germanium.

8. The semiconductor optical element according to claim 1 , wherein a Si 1-x Ge x (0≦x≦1) layer whose electrical conductivity is the same as electrical conductivity of the germanium light emitting layer or the light absorption layer is provided below the germanium light emitting layer or the light absorption layer.

9. The semiconductor optical element according to claim 1 , wherein the germanium light emitting layer or the light absorption layer, and the protective layer, the cladding layer, and the polysilicon layer are formed on a silicon substrate.

10. The semiconductor optical element according to claim 1 , wherein the germanium light emitting layer or the light absorption layer is formed thicker than the insulating layers on both sides.

11. The semiconductor optical element according to claim 10 , wherein the germanium light emitting layer or the light absorption layer is formed wider than a width of an opening portion of the insulating film, above an end of the opening portion.

12. The semiconductor optical element according to claim 1 , wherein a polysilicon layer whose conductive type is the same as a conductive type of the cladding layer is formed on the cladding layer.

13. The semiconductor optical element according to claim 12 , wherein the germanium light emitting layer or the light absorption layer, and the protective layer, the cladding layer, and the polysilicon layer are formed on an SOI substrate.

14. The semiconductor optical element according to claim 12 , wherein the germanium light emitting layer or the light absorption layer, and the protective layer, the cladding layer, and the polysilicon layer are formed on a GeOI substrate.

15. A semiconductor optical element comprising:
a substrate including silicon;
a n-type germanium buffer layer formed above the substrate;
a n-type germanium light emitting layer or an n-type germanium light absorption layer formed on the n-type germanium buffer layer;
a p-type germanium protective layer of non-light emission formed on the light emitting layer or the light absorption layer; and
a cladding layer including a p-type silicon-germanium mixed-crystal layer and formed on the p-type germanium protective layer.

16. The semiconductor optical element according to claim 15 , wherein the germanium light emitting layer or the light absorption layer has dimensions larger at a top end than at a lower end portion.

Assignees

• Okumura Tadashi
• Saito Shinichi
• Tani Kazuki
• Nomoto Etsuko
• Oda Katsuya
• Hitachi Ltd

Inventors

• Okumura Tadashi
• Saito Shinichi
• Tani Kazuki
• Nomoto Etsuko
• Oda Katsuya

Classifications

• H10H20/826 Primary

  comprising only Group IV materials · CPC title

• H10F30/221

  the potential barrier being a PN homojunction · CPC title

• H10F77/14

  Shape of semiconductor bodies; Shapes, relative sizes or dispositions of semiconductor regions within semiconductor bodies · CPC title

• H10H20/84

  Coatings, e.g. passivation layers or antireflective coatings · CPC title

• H01S5/2214

  based on oxides or nitrides · CPC title