Semiconductor light-emitting device having a current adjusting layer and a uneven shape light emitting region, and method for producing same

• US 5,814,839 A
• Filed: 02/14/1996
• Issued: 09/29/1998
• Est. Priority Date: 02/16/1995
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Hosoba, Hiroyuki
• Primary Examiner(s): TRAN, MINH LOAN
• Application Number:
  US08/600,008
• Time in Patent Office: 958 Days
• Field of Search: 257/94, 257/98, 257/101, 257/102, 372/45, 372/46, 372/48, 357/96, 357/99, 357/622, 357/627
• US Class Current: 257/96
• CPC Class Codes: H01L 33/145 with a current-blocking structure
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/24 of the light emitting region, e.g. non-planar junction
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/382 the electrode extending partially in or entirely through the semiconductor body
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector

Abstract

A current path adjusting layer composed of a current blocking region and a current passing region is provided on a layered structure including an active layer. An n-type electrode is provided above the current path adjusting layer so as to oppose the current blocking region. A p-type GaAs substrate has a groove-formed region where a plurality of grooves are formed, and the conductivities of the current path adjusting layer containing Zn and Se as dopants, grown on the substrate, depend upon an orientation of each slope of the grooves and that of a flat region of the substrate surface.

Claims

1. A semiconductor light-emitting device comprising:

a semiconductor substrate of first conductivity type having a top surface and a bottom surface;

a current path adjusting layer including a current blocking region and a current passing region, containing a first dopant of the first conductivity type and a second dopant of a second conductivity type;

a multi-layer structure formed between the top surface of the semiconductor substrate and the current path adjusting layer, the multi-layer structure including an active layer for emitting light and a pair of cladding layers sandwiching the active layer;

a first electrode formed on the bottom surface of the semiconductor substrate; and

a second electrode formed over the current blocking region of the current path adjusting layer,

wherein the top surface of semiconductor substrate has a flat region and a groove-formed region in which at least one groove is formed and conductivity of the current path adjusting layer is locally changed depending upon a crystal orientation of a slope of the groove and a crystal orientation of the flat region of the top surface of the semiconductor substrate, and

the current blocking region above the groove-formed region has the first conductivity and the current passing region above the flat region has the second conductivity.

2. A semiconductor light-emitting device according to claim 1, wherein the crystal orientation of the flat region of the top surface of the semiconductor substrate is (100), and the crystal orientation of the slope of the groove in the groove-formed region is A orientation.

3. A semiconductor light-emitting device according to claim 1, wherein a cladding layer having the second conductivity type is formed between the current path adjusting layer and the second electrode.

4. A semiconductor light-emitting device according to claim 1, further comprising a current diffusion layer having the second conductivity type formed between the current path adjusting layer and the second electrode, diffusing a current so that a cross-sectional of a current path becomes larger on the current path adjusting layer side than on the side of the second electrode.

5. A semiconductor light-emitting according to claim 4,

wherein the current diffusion layer includes a second current path adjusting layer therein,

the second current path adjusting layer contains a first dopant for the first conductivity type and a second dopant for the second conductivity type, and

the second current path adjusting layer includes a second current blocking region having a first conductivity type by the first dopant based on the crystal orientation of the slope of the groove in the groove-formed region of the semiconductor substrate and a second current passing region has the second conductivity by the second dopant based on the crystal orientation of the flat region of the semiconductor substrate.

6. A semiconductor light-emitting according to claim 1, wherein the current blocking region of the current path adjusting layer is a high-resistance region.

7. A semiconductor light-emitting according to claim 1, wherein the multi-layer structure includes a reflective layer reflecting generated in the active layer.

8. A semiconductor light-emitting according to claim 1, wherein the multi-layer structure is made of (Al_x Ga_1-x)_1-y In_y P layers (0≦

x≦

1, 0≦

y≦

1).

9. A semiconductor light-emitting device according to claim 1, wherein the current path adjusting layer is made of a (Al_x Ga_1-x)_1-y In_y P layer (0≦

x≦

1, 0≦

y≦

1).

10. A semiconductor light-emitting device according to claim 1, wherein the current diffusion layer is made of Al_x Ga_1-x As (0≦

x≦

1).

11. A semiconductor light-emitting device according to claim 1, wherein the current diffusion layer is made of a In_y (Ga_1-x Al_x)_1-y P layer (0≦

x≦

1, 0≦

y≦

1).

12. A semiconductor light-emitting device comprising:

a semiconductor substrate of a first conductivity type having a top surface and a bottom surface;

a multi-layer structure above the substrate including an active layer for emitting light and a pair of cladding layers sandwiching the active layer;

a current path adjusting layer formed between the top surface of the semiconductor substrate and the multi-layer structure, the current path adjusting layer including a current blocking region and a current passing region, containing a first dopant of the first conductivity type and a second dopant of a second conductivity type;

a first electrode formed on the bottom surface of the semiconductor substrate,

a second electrode formed over the current blocking region of the current path adjusting layer; and

wherein the top surface of semiconductor substrate has a flat region and a groove-formed region in which at least one groove is formed, and conductivity of the current path adjusting layer is locally changed depending upon a crystal orientation of a slope of the grooves and a crystal orientation of the flat region of the top surface of the semiconductor substrate, and

the current blocking region above the groove-formed region has the flat conductivity and the current passing region above the flat region has the second conductivity.

13. A semiconductor light-emitting device according to claim 12, wherein the current blocking region of the current path adjusting layer is a high-resistance region.

14. A semiconductor light-emitting device according to claim 12, wherein the semiconductor substrate comprises a second cladding layer having the first conductivity formed between the semiconductor substrate and the current path adjusting layer.

15. A semiconductor light-emitting device according to claim 14, comprising a current diffusion layer having the second conductivity, provided between the multi-layer structure and the second electrode diffusing a current so that a cross-sectional of a current path becomes larger on the layered structure side than on the side of the second electrode.

16. A semiconductor light-emitting device according to claim 15, wherein a reflective layer reflecting light generated in the active layer is formed on the semiconductor substrate.

17. A semiconductor light-emitting device according to claim 16, wherein the multi-layer structure is made of a (Al_x Ga_1-x)_1-y In_y P layer (0≦

x≦

1, 0≦

y≦

1).

18. A semiconductor light-emitting device according to claim 16, wherein the current path adjusting layer is made of a (Al_x Ga_1-x)_1-y In_y P layer (0≦

x≦

1, 0≦

y≦

1).

19. A semiconductor light-emitting device according to claim 16, wherein the current diffusion layer is made of Al_x Ga_1-x As (0≦

x≦

1).

20. A semiconductor light-emitting device according to claim 16, wherein the current diffusion layer is made of a In_y (Ga_1-x Al_x)_1-y P layer (0≦

x≦

1, 0≦

y≦

1).

21. A semiconductor light-emitting device comprising:

a semiconductor substrate of a first conductivity type having a top surface and a bottom surface;

a current path adjusting layer above the substrate including a current blocking region and a current passing region, containing a first dopant of the first conductivity type and a second dopant of a second conductivity type;

a multi-layer structure formed between the top surface of the semiconductor substrate and the current path adjusting layer, the multi-layer structure including an active layer for emitting light and a pair of cladding layers sandwiching the active layer;

a first electrode formed on the bottom surface of the semiconductor substrate; and

a second electrode formed over the current blocking region of the current path adjusting layer and said current passing region being substantially uncovered by the second electrode,

wherein the top surface of the semiconductor substrate has a flat region and a grooved region on top surface having at least one groove, and conductivity of the current path adjusting layer is locally changed depending upon a crystal orientation of a slope of the at least one groove and a crystal orientation of the flat region of the top surface of the semiconductor substrate, and

the current blocking region above the flat region has the first conductivity type and the current passing region above the grooved region has the second conductivity type.

22. A semiconductor light-emitting device according to claim 21, comprising a current diffusion layer having the second conductivity formed between the current path adjusting layer and the second electrode, diffusing a current so that a cross-section of a current path becomes larger on the current path adjusting layer side than on the side of the second electrode.

23. A semiconductor light-emitting device according to claim 21, wherein the current blocking region is a high-resistance region.

24. A semiconductor light-emitting device according to claim 21, wherein a reflective layer reflecting light generated in the active layer is formed on the semiconductor substrate.

25. A semiconductor light-emitting device comprising:

a semiconductor substrate of a first conductivity type having a top surface and a bottom surface;

a current path adjusting layer above the substrate including a current blocking region and a current passing region, containing a first dopant of the first conductivity type and a second dopant of a second conductivity type;

a multi-layer structure formed between the top surface of the semiconductor substrate and the current path adjusting layer, the multi-layer structure including an active layer for emitting light and a pair of cladding layers sandwiching the active layer;

a first electrode formed on the bottom surface of the semiconductor substrate; and

a second electrode formed over the current blocking region of the current path adjusting layer;

wherein the top surface of the semiconductor substrate has a flat region and a grooved region on the top surface, and conductivity of the current path adjusting layer is locally changed depending upon a crystal orientation of a slope of the grooved region and a crystal orientation of the flat region of the top surface of the semiconductor substrate, and

the current blocking region above the flat region has the flat conductivity type and the current region above the grooved region has the second conductivity type;

further comprising a current diffusion layer having the second conductivity formed between the current path adjusting layer and the second electrode, diffusing a current so that a cross-section of a current path becomes larger on the current path adjusting layer side than on the side of the second electrode;

wherein the current diffusion layer includes a second current path adjusting layer,

the second current path adjusting layer contains a first dopant for the first conductivity and a second dopant for the second conductivity, and

the second current path adjusting layer includes a second current blocking region formed so as to have a conductivity of the first dopant based on the orientation of the flat region of the semiconductor substrate and a second current passing region formed so as to have a conductivity of the second dopant based on the orientation of the slope of the grooved region of the semiconductor substrate.

26. A semiconductor light-emitting device comprising:

a semiconductor substrate of a first conductivity type having a top surface and a bottom;

a multi-layer structure including an active for emitting light and a pair of cladding layers sandwiching the active layer;

a current path adjusting layer formed between the top surface of the semiconductor substrate and the multi-layer structure, the current path adjusting layer including a current blocking region and a current passing region, containing a first dopant of the first conductivity type and a second dopant for a second conductivity type;

a first electrode formed on the bottom surface of the semiconductor substrate; and

a second electrode formed over the current blocking region of the current path adjusting layer and said second electrode being substantially confined to an area over the current blocking region,

wherein the top surface of the semiconductor substrate has a flat region and a grooved region in which grooves are formed, and conductivity of the current path adjusting layer locally changed depending upon a crystal orientation of slopes of the grooves and a crystal orientation of the flat region of the top surface of the semiconductor substrate, and

the current blocking region above the flat region has the second conductivity type and the current passing region above the grooved region has the first conductivity type.

27. A semiconductor light-emitting device according to claim 26, wherein the current blocking region is a high-resistance region.

28. A semiconductor light-emitting device according to claim 26, comprising a current diffusion layer having the second conductivity provided between the multi-layer structure and the second electrode, and wherein a current is diffused by the current diffusion layer so that a cross-section of a current path becomes larger on the layered structure side than on the side of the second electrode.

29. A semiconductor light-emitting device according to claim 28, wherein a reflective layer reflecting light generated in the active layer is formed on the semiconductor substrate.

30. A semiconductor light-emitting device comprising:

a semiconductor substrate with a top surface with an uneven shape, and having a first conductivity type;

a current path adjusting layer above the substrate including a current blocking region and a current passing region, containing a first dopant of the first conductivity type and a second dopant conductivity type;

a light-emitting portion including an active layer and a pair of cladding layers sandwiching the active layer, the light-emitting portion disposed on the top surface of the semiconductor substrate, emitting light generated in the active layer;

a first electrode formed on a bottom surface of the semiconductor substrate; and

a second electrode formed over the light-emitting portion and being substantially confined to an area above the current blocking region of the current adjusting layer,

wherein each semiconductor layer included in the light-emitting portion has a front face with an uneven corresponding to the uneven shape of the top surface of the semiconductor substrate.

31. A semiconductor light-emitting device according to claim 30,

wherein a plurality of strip-shaped grooves are formed on the top surface of the semiconductor substrate of the semiconductor substrate so that the top surface becomes uneven, and

an orientation of slopes of the grooves is an A-plane with respect to a (100) plane of semiconductor crystal.

32. A semiconductor light-emitting device according to claim 30, wherein the top surface of the semiconductor substrate is tilted in a 011! direction from the (100) plane of semiconductor crystal.

33. A semiconductor light-emitting device according to claim 30, wherein the top surface of the semiconductor substrate includes a plane tilted in a 011! direction from a (100) plane semiconductor crystal and a (100) plane.