LIGHT EMITTING DIODES

• US 20130210180A1
• Filed: 07/25/2011
• Published: 08/15/2013
• Est. Priority Date: 07/26/2010
• Status: Abandoned Application

• Current Assignee: Seren Photonics Limited
• Original Assignee: Seren Photonics Limited
• Inventors: Wang, Tao
• Application Number:
  US13/812,325
• Publication Number:
  US 20130210180A1
• Time in Patent Office: Days
• US Class Current: 438/29
• CPC Class Codes: H01L 21/3006 of AIIIBV compounds
• CPC Class Codes: H01L 33/0075 comprising nitride compounds
• CPC Class Codes: H01L 33/0095 Post-treatment of devices, e.g. annealing, recrystallisation or short-circuit elimination
• CPC Class Codes: H01L 33/08 with a plurality of light emitting regions, e.g. laterally discontinuous light emitting layer or photoluminescent region integrated within the semiconductor body H01L27/15 takes precedence
• CPC Class Codes: H01L 33/32 containing nitrogen

Abstract

A method of producing a light emitting device comprises providing a wafer structure including a light emitting layer of III-nitride semiconductor material; dry etching the wafer at least part way through the light emitting layer so as to leave exposed surfaces of the emitting layer; and treating the exposed surfaces of the emitting layer with a plasma. The treatment may be using hot nitric acid or a hydrogen plasma.

Claims

1. A method of producing a light emitting device comprising:

providing a wafer structure including a light emitting layer of III-nitride semiconductor material;

dry etching the wafer at least part way through the light emitting layer so as to leave exposed surfaces of the emitting layer; and

treating the exposed surfaces of the emitting layer with nitric acid at a temperature of at least 100°

C.

2. A method according to claim 1 wherein the light emitting layer includes at least one of InGaN, GaN, AlGaN and GaN.

3. A method according to claim 2 wherein the emitting layer comprises adjacent layers of GaN, and at least one of AlGaN and InGaN.

4. A method according to claim 1 wherein said temperature is at least 200°

C.

5. A method according to claim 4 wherein said temperature is at least 250°

C.

6. A method according to claim 1 wherein the nitric acid is at a concentration of at least 50%.

7. A method according to claim 1 wherein the surfaces are treated with the nitric acid for at least 1 minute.

8. A method according to claim 7 wherein the surfaces are treated with the nitric acid for at least 3 minutes.

9. A method of producing a light emitting device comprising:

providing a wafer structure including a light emitting layer of III-nitride semiconductor material;

dry etching the wafer at least part way through the light emitting layer so as to leave exposed surfaces of the emitting layer; and

treating the exposed surfaces of the emitting layer with a plasma.

10. A method according to claim 9 wherein the plasma is hydrogen plasma.

11. A method according to claim 9 wherein the plasma is at a pressure of from 5 to 100 mTorr.

12. A method according to claim 9 wherein the plasma is produced by introducing a gas into a chamber and applying a radio frequency signal to it via at least one electrode.

18. A method according to claim 9 wherein the plasma is at a pressure of at least 20 mTorr.

19. A method according to claim 9 wherein the plasma is at a pressure of not more than 50 mTorr.

13. A method of producing a light emitting device comprising:

providing a wafer structure including a light emitting layer of III-nitride semiconductor material;

dry etching the wafer so as to leave a plurality of pillars having exposed surfaces, and

performing a surface modification step to modify the exposed surfaces so as enhance the optical performance of the device.

14. A method according to claim 13 wherein the material has a surface region which has a Fermi energy, and the surface modification includes changing said Fermi energy.

15. A method according to claim 13 wherein the material has surface states, and the surface modification includes at least one of reducing and eliminating said surface states.

16. A method according to claim 14 wherein the pillars each have a main body having a main body Fermi energy and the surface modification comprises changing the Fermi level in the surface region towards the main body Fermi energy.

17. (canceled)