Light-emitting gallium nitride-based III-V group compound semiconductor device and manufacturing method thereof

• US 20080303034A1
• Filed: 11/13/2007
• Published: 12/11/2008
• Est. Priority Date: 06/08/2007
• Status: Active Grant

• Current Assignee: Epistar Corporation (Ennostar, Inc.)
• Original Assignee: Formosa Epitaxy Incorporated (Ennostar, Inc.)
• Inventors: Huang, Kuo-Chin, Pan, Shyi-Ming, Huang, Cheng-Kuo, Chien, Fen-Ren, Chuang, Chi-Yang
• Granted Patent: US 8,263,991 B2
• Time in Patent Office: Days
• US Class Current: 257/76
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/40 Materials therefor
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector

Abstract

A light-emitting gallium nitride-based III-V group compound semiconductor device and a manufacturing method thereof are disclosed. The light emitting device includes a substrate, a n-type semiconductor layer over the substrate, an active layer over the n-type semiconductor layer, a p-type semiconductor layer over the active layer, a conductive layer over the p-type semiconductor layer, a first electrode disposed on the conductive layer and a second electrode arranged on exposed part of the n-type semiconductor layer. A resistant reflective layer or a contact window is disposed on the p-type semiconductor layer, corresponding to the first electrode so that current passes beside the resistant reflective layer or by the contact window to the active layer for generating light. When the light is transmitted to the conductive layer for being emitted, it is not absorbed or shielded by the first electrode. Thus the current is distributed efficiently over the conductive layer. Therefore, both LED brightness and efficiency are improved. Moreover, adhesion between the conductive layer and the p-type semiconductor layer is improved so that metal peel-off problem during manufacturing processes can be improved.

Claims

1. A light-emitting gallium nitride-based III-V group compound semiconductor device comprising:

a substrate;

a n-type semiconductor layer disposed over the substrate;

an active layer arranged over the n-type semiconductor layer and part of the n-type semiconductor layer is exposed;

a p-type semiconductor layer arranged over the active layer;

a resistant and reflective layer disposed over the p-type semiconductor layer;

a conductive layer arranged over the p-type semiconductor layer as well as the resistant and reflective layer;

a first electrode disposed on the conductive layer and corresponding to the resistant and reflective layer;

a second electrode arranged on exposed part of the n-type semiconductor layer;

wherein after applying a voltage to the first electrode and the second electrode, a current is generated and is passing beside the resistant and reflective layer to the active layer so as to make the active layer generate light while the light passes through the resistant and reflective layer and emits out effectively without being shielded or absorbed by the first electrode and the current is effectively spread over the active layer.

2. The device as claimed in claim 1, wherein the resistant and reflective layer is a dielectric reflective layer, a metal reflective layer or combinations of them.

3. The device as claimed in claim 2, wherein the dielectric reflective layer is made from silicon dioxide, silicon monoxide, silicon tetranitride, nitride, amorphous semiconductor, non-crystal semiconductor, zinc oxide, nickel oxide, titanium dioxide, oxide or combinations of them.

4. The device as claimed in claim 2, wherein the dielectric reflective layer is made from combinations of at least two materials with different refractive index.

5. The device as claimed in claim 2, wherein the metal reflective layer comprising a plurality of metal particles.

6. A manufacturing method of light-emitting gallium nitride-based III-V group compound semiconductor devices comprising the steps of:

providing a substrate;

forming a n-type semiconductor layer over the substrate;

forming an active layer over the n-type semiconductor layer;

forming a p-type semiconductor layer over the active layer;

performing an etching process to expose part of the n-type semiconductor layer;

forming a resistant and reflective layer over the p-type semiconductor layer;

forming a conductive layer over the resistant and reflective layer and the p-type semiconductor layer;

forming a first electrode that is corresponding to the resistant and reflective layer over the conductive layer;

forming a second electrode over exposed part of the n-type semiconductor layer.

7. The method as claimed in claim 6, wherein the resistant and reflective layer is a dielectric reflective layer, a metal reflective layer or combinations of them.

8. The method as claimed in claim 7, wherein the dielectric reflective layer is made from silicon dioxide, silicon monoxide, silicon tetranitride, nitride, amorphous semiconductor, non-crystal semiconductor, zinc oxide, nickel oxide, titanium dioxide, oxide or combinations of them.

9. The method as claimed in claim 7, wherein the dielectric reflective layer is made from combinations of at least two materials with different refractive index.

10. The method as claimed in claim 7, wherein the metal reflective layer comprising a plurality of metal particles.

11. A light-emitting gallium nitride-based III-V group compound semiconductor device comprising:

a substrate;

a n-type semiconductor layer disposed over the substrate;

an active layer arranged over the n-type semiconductor layer and part of the n-type semiconductor layer is exposed;

a p-type semiconductor layer having a contact window arranged over the active layer;

a conductive layer arranged over the p-type semiconductor layer;

a first electrode disposed on the conductive layer and corresponding to the contact window; and

a second electrode arranged on exposed part of the n-type semiconductor layer;

wherein after applying a voltage to the first electrode and the second electrode, a current is generated and is passing beside the contact window so as to spread the current effectively over the active layer.

12. The device as claimed in claim 11, wherein the contact window is formed by an etching process or an ion implantation process.

13. The device as claimed in claim 11, wherein a resistant and reflective layer is arranged over the contact window.

14. The device as claimed in claim 13, wherein the resistant and reflective layer is a dielectric reflective layer, a metal reflective layer or combinations of them.

15. The device as claimed in claim 14, wherein the dielectric reflective layer is made from silicon dioxide, silicon monoxide, silicon tetranitride, nitride, amorphous semiconductor, non-crystal semiconductor, zinc oxide, nickel oxide, titanium dioxide, oxide or combinations of them.

16. The device as claimed in claim 14, wherein the dielectric reflective layer is made from combinations of at least two materials with different refractive index.

17. The device as claimed in claim 14, wherein the metal reflective layer comprising a plurality of metal particles.

18. A manufacturing method of light-emitting gallium nitride-based III-V group compound semiconductor devices comprising the steps of:

providing a substrate;

forming a n-type semiconductor layer over the substrate;

forming an active layer over the n-type semiconductor layer;

forming a p-type semiconductor layer over the active layer;

forming a contact window on the p-type semiconductor layer;

performing an etching process to expose part of the n-type semiconductor layer;

forming a conductive layer over the contact window and the p-type semiconductor layer;

forming a first electrode over the conductive layer and corresponding to the contact window; and

forming a second electrode over exposed part of the n-type semiconductor layer.

19. The method as claimed in claim 18, wherein the contact window is formed by an etching process or an ion implantation process.

20. The method as claimed in claim 18, wherein a resistant and reflective layer is arranged over the contact window.

21. The method as claimed in claim 20, wherein the resistant and reflective layer is a dielectric reflective layer, a metal reflective layer or combinations of them.

22. The method as claimed in claim 21, wherein the dielectric reflective layer is made from silicon dioxide, silicon monoxide, silicon tetranitride, nitride, amorphous semiconductor, non-crystal semiconductor, zinc oxide, nickel oxide, titanium dioxide, oxide or combinations of them.

23. The method as claimed in claim 21, wherein the dielectric reflective layer is made from combinations of at least two materials with different refractive index.

24. The method as claimed in claim 21, wherein the metal reflective layer comprising a plurality of metal particles.