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

• US 8,263,991 B2
• Filed: 11/13/2007
• Issued: 09/11/2012
• 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, Chuang, Chi-Yang, Chien, Fen-Ren
• Primary Examiner(s): Tran, Long
• Assistant Examiner(s): KLEIN, JORDAN M
• Application Number:
  US11/979,963
• Publication Number:
  US 20080303034A1
• Time in Patent Office: 1,764 Days
• Field of Search: 257/94, 257/98, 257/103, 257/E33.062, 257/E33.068
• US Class Current: 257/98
• 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;

an n-type semiconductor layer disposed over the substrate, said n-type semiconductor layer having an exposed and non-exposed areas;

an active layer arranged over said non-exposed area of the n-type semiconductor layer, said active layer generating light;

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

a resistant and reflective layer including a reflective layer made from a material selected from a group consisting of a metal and a dielectric, and being disposed over the p-type semiconductor layer, said resistant and reflective layer redirecting electrical current directed thereto toward areas surrounding said resistant and reflective layer, wherein the reflective layer is made from combinations of at least two materials with different refractive indices and the reflective layer is the bottom of the resistant and reflective layer and is disposed on the p-type semiconductor layer;

a conductive layer arranged over the p-type semiconductor layer and the resistant and reflective layer, said conductive layer being in contiguous contact with said p-type semiconductor layer around said resistant and reflective layer;

a first electrode disposed on the conductive layer and corresponding to the resistant and reflective layer, the first electrode having side surfaces in vertically aligned relationship with corresponding side surfaces of the resistant and reflective layer;

a second electrode arranged on said exposed area of the n-type semiconductor layer, said second electrode being laterally displaced from said first electrode;

wherein, upon applying a voltage to the first electrode and the second electrode, a current is generated and passes to said active layer around the resistant and reflective layer, thereby causing the active layer to generate the light, wherein the light passes through the resistant and reflective layer and emits from said light-emitting device effectively.

2. The device as claimed in claim 1, wherein the resistant and reflective layer further includes combinations of said dielectric and metal reflective layers.

3. The device as claimed in claim 1, 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 1, wherein the metal reflective layer comprises a plurality of metal particles.

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

a substrate;

an n-type semiconductor layer disposed over the substrate, said n-type semiconductor layer having an exposed and a non-exposed areas;

an active layer arranged over said non-exposed area of the n-type semiconductor layer, said active layer generating light;

a p-type semiconductor layer disposed on said active layer and having a contact window formed therein;

a resistant and reflective layer received within said contact window and including a reflective layer made from a material selected from a group consisting of a metal and a dielectric, said resistant and reflective layer redirecting electrical current directed thereto toward areas surrounding said resistant and reflective layer, wherein the dielectric reflective layer is made from combinations of at least two materials with different refractive indices;

a conductive layer arranged over said contact window formed in the p-type semiconductor layer and said resistant and reflective layer within said contact window;

a first electrode disposed on the conductive layer and in correspondence with the contact window, said resistant and reflective layer being separated from said first electrode by said conductive layer, the first electrode having side surfaces in vertically aligned relationship with corresponding side surfaces of the resistant and reflective layer; and

a second electrode arranged on said exposed area of the n-type semiconductor layer, said second electrode being laterally displaced from said first electrode;

wherein, upon applying a voltage to the first electrode and the second electrode, a current is generated and passes to said active layer around the contact window filled with said resistant and reflective layer, and wherein the generated current is effectively spread over the active layer.

6. The device as claimed in claim 5, wherein the contact window is formed by an etching process or an ion implantation process.

7. The device as claimed in claim 5, wherein the resistant and reflective layer further includes combinations of said dielectric and metal reflective layers.

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