Semiconductor device with roughened surface increasing external quantum efficiency

• US 6,441,403 B1
• Filed: 10/14/2000
• Issued: 08/27/2002
• Est. Priority Date: 06/23/2000
• Status: Expired due to Term

• Current Assignee: Epistar Corporation (Ennostar, Inc.)
• Original Assignee: United Epitaxy Company, Ltd. (Ennostar, Inc.)
• Inventors: Tsai, Tzong-Liang, Chang, Chih-Sung, Chang, Chung-Ying
• Primary Examiner(s): CRANE, SARA W
• Application Number:
  US09/688,605
• Time in Patent Office: 682 Days
• Field of Search: 257/94, 257/96, 257/97, 257/98, 257/103
• US Class Current: 257/94
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/32 containing nitrogen

Abstract

The present invention provides a semiconductor device with a roughened surface that increases external quantum efficiency thereof. Roughening of the semiconductor device surface is done by epitaxial growth techniques that may include hydride vapor phase epitaxy (HVPE) technique, organometallic vapor phase epitaxy (OMVPE) technique, or molecular beam epitaxy (MBE) technique.

Claims

1. A light emitting device of semiconductor, comprising:

a substrate;

an Al_xIn_yGa<sub>1−

x−

y</sub>N buffer layer which is grown on the substrate, wherein 0≦

x≦

1, 0≦

y≦

1, and 0≦

x+y≦

1;

a n-type Al_sIn_tGa<sub>1−

s−

t</sub>N epitaxial layer which is grown on the buffer layer, wherein 0≦

s≦

1, 0≦

t≦

1, and 0≦

s+t≦

1;

an InGaN active layer that is grown on the n-type epitaxial layer;

a p-type Al_uIn_vGa<sub>1−

u−

v</sub>N epitaxial layer which is grown on the active layer, wherein 0≦

u≦

1, 0≦

v≦

1, and 0≦

u+v≦

1; and

a p-type Al_pIn_qGa<sub>1−

p−

q</sub>N rough layer which is grown on the p-type epitaxial layer, wherein 0≦

p≦

1, 0≦

q≦

1, and 0≦

p+q≦

1;

wherein the p-type rough layer is grown at a temperature between 400°

C. and 1000°

C.

2. The light emitting device of claim 1, wherein the p-type rough layer is grown at a rate between 10 Å

/min and 1000 Å

/min.

3. The light emitting device of claim 1, wherein a V/III ratio of the p-type rough layer is between 1000 and 500000.

4. The light emitting device of claim 1, wherein the substrate is composed of aluminum oxide, silicon carbide, or GaAs.

5. The light emitting device of claim 1, wherein the n-type epitaxial layer is doped with Si, Ge, or Tn.

6. The light emitting device of claim 1, wherein the InGaN active layer comprises a double-hetero structure or a quantum well structure.

7. A light emitting device of semiconductor, comprising:

a substrate;

an Al_xIn_yGa<sub>1−

x−

y</sub>N buffer layer which is grown on the substrate, wherein 0≦

x≦

1, 0≦

y≦

1, and 0≦

x+y≦

1;

a n-type Al_sIn_tGa<sub>1−

s−

t</sub>N epitaxial layer which is grown on the buffer layer, wherein 0≦

s≦

1, 0≦

t≦

1, and 0≦

s+t≦

1;

an InGaN active layer that is grown on the n-type epitaxial layer;

a p-type Al_uIn_vGa<sub>1−

u−

v</sub>N rough layer which is grown on the active layer, wherein 0≦

u≦

1, 0≦

v≦

1, and 0≦

u+v≦

1;

wherein the p-type rough layer is grown at a temperature between 400°

C. and 10000°

C.

8. The light emitting device of claim 7, wherein the p-type rough layer is grown at a rate between 10 Å

/min and 1000 Å

/min.

9. The light emitting device of claim 7, wherein a V/III ratio of the p-type rough layer is between 1000 and 500000.

10. The light emitting device of claim 7, wherein the substrate is composed of aluminum oxide, silicon carbide, or GaAs.

11. The light emitting device of claim 7, wherein the n-type epitaxial layer is doped with Si, Ge, or Tn.

12. The light emitting device of claim 7, wherein the InGaN active layer comprises a double-hetero structure or a quantum well structure.

13. A light emitting device of semiconductor, comprising:

a substrate;

an Al_xIn_yGa<sub>1−

x−

y</sub>N buffer layer which is grown on the substrate, wherein 0≦

x≦

1, 0≦

y≦

1, and 0≦

x+y≦

1;

a p-type Al_sIn_tGa<sub>1−

s−

t</sub>N epitaxial layer which is grown on the buffer layer, wherein 0≦

s≦

1, 0≦

t≦

1, and 0≦

s+t≦

1;

an InGaN active layer that is grown on the p-type epitaxial layer;

a n-type Al_uIn_vGa<sub>1−

u−

v</sub>N epitaxial layer which is grown on the active layer, wherein 0≦

u≦

1, 0≦

v≦

1, and 0≦

u+v≦

1; and

a n-type A_pIn_qGa<sub>1−

p−

q</sub>N rough layer which is grown on the n-type epitaxial layer, wherein 0≦

p≦

1, 0≦

q≦

1, and 0≦

p+q≦

1;

wherein the n-type rough layer is grown at a temperature between 400°

C. and 1000°

C.

14. The light emitting device of claim 13, wherein the n-type rough layer is grown at a rate between 10 Å

/min and 1000 Å

/min.

15. The light emitting device of claim 13, wherein a V/III ratio of the n-type rough layer is between 1000 and 500000.

16. The light emitting device of claim 13, wherein the substrate is composed of aluminum oxide, silicon carbide, or GaAs.

17. The light emitting device of claim 13, wherein the p-type epitaxial layer is doped with Zn, Cd, Be, Mg, Ca, or Ba.

18. The light emitting device of claim 13, wherein the InGaN active layer comprises a double-hetero structure or a quantum well structure.

19. A light emitting device of semiconductor, comprising:

a substrate;

an Al_xIn_yGa<sub>1−

x−

y</sub>N buffer layer which is grown on the substrate, wherein 0≦

x≦

1, 0≦

y≦

1, and 0≦

x+y≦

1;

a p-type Al_sIn_tGa<sub>1−

s−

t</sub>N epitaxial layer which is grown on the buffer layer, wherein 0≦

s≦

1, 0≦

t≦

1, and 0≦

s+t≦

1;

an InGaN active layer that is grown on the p-type epitaxial layer;

a n-type Al_uIn_vGa<sub>1−

u−

v</sub>N rough layer which is grown on the active layer, wherein 0≦

u≦

1, 0≦

v≦

1, and 0≦

u+v≦

1;

wherein the n-type rough layer is grown at a temperature between 400°

C. and 1000°

C.

20. The light emitting device of claim 19, wherein the n-type rough layer is grown at a rate between 10 Å

/min and 1000 Å

/min.

21. The light emitting device of claim 19, wherein a V/Ill ratio of the n-type rough layer is between 1000 and 500000.

22. The light emitting device of claim 19, wherein the substrate is composed of aluminum oxide, silicon carbide, or GaAs.

23. The light emitting device of claim 19, wherein the p-type epitaxial layer is doped with Zn, Cd, Be, Mg, Ca, or Ba.

24. The light emitting device of claim 19, wherein the InGaN active layer comprises a double-hetero structure or a quantum well structure.