SEMICONDUCTOR LIGHT EMITTING DEVICE AND METHOD FOR MANUFACTURING THE SAME

• US 20130234178A1
• Filed: 08/31/2012
• Published: 09/12/2013
• Est. Priority Date: 02/01/2012
• Status: Abandoned Application

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Mitsugi, Satoshi, Sugiyama, Naoharu, Sato, Taisuke, Nunoue, Shinya
• Application Number:
  US13/601,015
• Publication Number:
  US 20130234178A1
• Time in Patent Office: Days
• US Class Current: 257/94
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/12 with a stress relaxation structure, e.g. buffer layer
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

According to one embodiment, a semiconductor light emitting device includes a silicon substrate, a buffer layer, a foundation semiconductor layer, a first semiconductor layer, a light emitting unit and a second semiconductor layer. The buffer layer is provided on a part of a major surface of the silicon substrate. The foundation semiconductor layer is crystal-grown from an upper surface of the buffer layer, covers a non-formed region of the major surface where the buffer layer is not provided, and is spaced apart from the non-formed region. The first semiconductor layer is provided on the foundation semiconductor layer and has a first conductivity type. The light emitting unit is provided on the first semiconductor layer. The second semiconductor layer is provided on the light emitting unit and has a second conductivity type.

Claims

1. A semiconductor light emitting device comprising:

a silicon substrate having a major surface;

a buffer layer provided on a part of the major surface;

a foundation semiconductor layer crystal-grown from an upper surface of the buffer layer, the foundation semiconductor layer covering a non-formed region of the major surface where the buffer layer is not provided, the foundation semiconductor layer being spaced apart from the non-formed region;

a first semiconductor layer of a first conductivity type provided on the foundation semiconductor layer;

a light emitting unit provided on the first semiconductor layer; and

a second semiconductor layer of a second conductivity type provided on the light emitting unit.

2. The device according to claim 1, wherein a ratio of a sectional area of the buffer layer cut along a plane parallel to the major surface to an area of the major surface is larger than 5% and less than 50%.

3. The device according to claim 1, wherein a distance between the major surface of the silicon substrate in the non-formed region and the foundation semiconductor layer is equal to or larger than ⅓

of a peak wavelength of a light emitted from the light emitting unit.

4. The device according to claim 1, wherein a gap and the buffer layer form Total Internal Reflection, the gap being provided between the foundation semiconductor layer and the non-formed region.

5. The device according to claim 1, wherein an impurity concentration in the foundation semiconductor layer is lower than an impurity concentration in the first semiconductor layer.

6. The device according to claim 1, wherein a space between the major surface of the silicon substrate in the non-formed region and the foundation semiconductor layer is in a reduced-pressure state or filled with a gas.

7. The device according to claim 1, further comprising a low-refractive-index layer provided in at least a part of a space between the major surface of the silicon substrate in the non-formed region and the foundation semiconductor layer, the low-refractive-index layer having a refractive index lower than the refractive index of the buffer layer.

8. The device according to claim 1, wherein a refractive index of the buffer layer is lower than a refractive index of the foundation semiconductor layer.

9. The device according to claim 1, wherein

the buffer layer includes a nitride semiconductor including aluminum, and

the foundation semiconductor layer, the first semiconductor layer, the light emitting unit, and the second semiconductor layer include a nitride semiconductor.

10. The device according to claim 1, wherein the non-formed region of the major surface of the silicon substrate is recessed from the part where the buffer layer is provided on the major surface.

11. The device according to claim 1, wherein the buffer layer is continuous, the non-formed region is provided in a plurality, and the plurality of the non-formed regions have an island-like shape.

12. The device according to claim 1, wherein the non-formed region is continuous, the buffer layer is provided in a plurality, and the plurality of buffer layers have an island-like shape.

13. The device according to claim 1, wherein a thickness of a gap provided between the foundation semiconductor layer and the non-formed region is 1 micrometer or less.

14. The device according to claim 1, wherein the buffer layer includes a plurality of first layers and a second layer provided between the first layers, and the second layer has a refractive index different from a refractive index of the first layer.

15. The device according to claim 1, further comprising:

a first electrode;

a light transmissive electrode; and

a light transmissive electrode,

the first semiconductor layer having a first part and a second part arranged with the first part in a direction from the first semiconductor layer toward the second semiconductor layer,

the first electrode being provided on the second part,

the light emitting unit being provided on a first part,

the light transmissive electrode being provided on the second semiconductor layer and being light transmissive to a light emitted from the light emitting unit, and

the second electrode being provided on the light transmissive electrode.

16. The device according to claim 15, wherein a lower surface of a portion facing the non-formed region of the foundation semiconductor layer is located lower than a lower surface of the first electrode.

17. The device according to claim 15, wherein the light transmissive electrode has an unevenness provided on an upper surface of the light transmissive electrode.

18. The device according to claim 15, further comprising:

an electronic circuit provided on the silicon substrate,

at least a part of the electronic circuit is electrically connected to at least one of the first semiconductor layer and the second semiconductor layer.

19. A method for manufacturing a semiconductor light emitting device, comprising:

forming a buffer layer on a part of a major surface of a silicon substrate;

laterally crystal-growing a foundation semiconductor layer from an upper surface of the buffer layer, the foundation semiconductor layer covering a non-formed region where the buffer layer is not provided on the major surface, the foundation semiconductor layer being spaced apart from the non-formed region;

crystal-growing a first semiconductor layer of a first conductivity type on the foundation semiconductor layer;

crystal-growing a light emitting unit on the first semiconductor layer; and

crystal-growing a second semiconductor layer of a second conductivity type on the light emitting unit.

20. The method according to claim 19, wherein

the crystal-growing the foundation semiconductor layer includes forming Total Internal Reflection mirror from a gap and the buffer layer, the gap being provided between the foundation semiconductor layer and the non-formed region.