Semiconductor light emitting device

• US 8,946,752 B2
• Filed: 09/04/2013
• Issued: 02/03/2015
• Est. Priority Date: 09/11/2012
• Status: Active Grant

• Current Assignee: ROHM Co., Ltd.
• Original Assignee: ROHM Co., Ltd.
• Inventors: Shinohara, Toshikuni, Kawase, Tomohito
• Primary Examiner(s): YUSHIN, NIKOLAY K
• Application Number:
  US14/017,957
• Publication Number:
  US 20140070253A1
• Time in Patent Office: 517 Days
• Field of Search: 257/98, 257/88, 257/79
• US Class Current: 257/98
• CPC Class Codes: H01L 2933/0083 Periodic patterns for optical field-shaping in or on the semiconductor body or semiconductor body package, e.g. photonic bandgap structures
• CPC Class Codes: H01L 33/0091 for devices with an active region comprising only IV-VI compounds
• CPC Class Codes: H01L 33/10 with a light reflecting structure, e.g. semiconductor Bragg reflector
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/465 with a resonant cavity structure

Abstract

The semiconductor device includes a substrate, a semiconductor layer which is formed on the substrate and includes a light emitting layer, and a diffraction/scattering film for diffracting or scattering light generated at the light emitting layer. The diffraction/scattering film is formed between the light emitting layer and the substrate, has a side surface slanted with respect to a film thickness direction thereof, and has a composition gradient in the film thickness direction.

Claims

1. A semiconductor light emitting device comprising:

a substrate;

a semiconductor layer which is formed on the substrate and includes a light emitting layer; and

a diffraction/scattering film, which is formed between the light emitting layer and the substrate, for diffracting or scattering light generated at the light emitting layer, the diffraction/scattering film having a side surface slanted with respect to a film thickness direction thereof and having a composition gradient in the film thickness direction, the diffraction/scattering film including a film portion having a gradient oxygen composition which decreases monotonically from the substrate toward the light emitting layer.

2. The semiconductor light emitting device according to claim 1, wherein the diffraction/scattering film includes silicon and nitrogen, and a composition of nitrogen has a gradient in the film thickness direction.

4. The semiconductor light emitting device according to claim 1, wherein the diffraction/scattering film includes a film portion having a composition varying in the film thickness direction from SiO₂ to SiN.

5. The semiconductor light emitting device according to claim 1, wherein the diffraction/scattering film includes a film portion having a composition varying in the film thickness direction from SiON to SiN.

6. The semiconductor light emitting device according to claim 1, wherein the diffraction/scattering film includes a film portion of SiO_aN_b in which a composition a (a>

0) of oxygen and a composition b (b>

0) of nitrogen vary in the film thickness direction.

7. The semiconductor light emitting device according to claim 1, wherein the diffraction/scattering film includes a film portion of SiN_x having a nitrogen composition x varying in the film thickness direction.

8. The semiconductor light emitting device according to claim 1, wherein the diffraction/scattering film includes a film portion having a gradient nitrogen composition which increases monotonically from the substrate toward the light emitting layer.

9. The semiconductor light emitting device according to claim 1, wherein the diffraction/scattering film includes a film portion having an oxygen composition larger than a nitrogen composition.

10. The semiconductor light emitting device according to claim 1, wherein the diffraction/scattering film includes a film portion having a nitrogen composition larger than an oxygen composition.

11. The semiconductor light emitting device according to claim 1, wherein the diffraction/scattering film has a constant silicon composition in the film thickness direction.

3. A semiconductor light emitting device comprising:

a substrate;

a semiconductor layer which is formed on the substrate and includes a light emitting layer; and

a diffraction/scattering film, which is formed between the light emitting layer and the substrate, for diffracting or scattering light generated at the light emitting layer, the diffraction/scattering film having a side surface slanted with respect to a film thickness direction thereof and having a composition gradient in the film thickness direction,

wherein the diffraction/scattering film includes a film portion having a linear-gradient composition in the film thickness direction.

14. The semiconductor light emitting device according to claim 3, wherein the diffraction/scattering film includes silicon, nitrogen and oxygen, and a composition of nitrogen and a composition of oxygen have a gradient in the film thickness direction.

12. A semiconductor light emitting device comprising:

a substrate;

a semiconductor layer which is formed on the substrate and includes a light emitting layer; and

a diffraction/scattering film, which is formed between the light emitting layer and the substrate, for diffracting or scattering light generated at the light emitting layer, the diffraction/scattering film having a side surface slanted with respect to a film thickness direction thereof and having a composition gradient in the film thickness direction,

wherein the diffraction/scattering film includes a film portion having a composition varying in the film thickness direction from SiO₂ to SiON.

13. The semiconductor light emitting device according to claim 12, wherein the diffraction/scattering film includes a film portion having a gradient oxygen composition which decreases monotonically from the substrate toward the light emitting layer.