Nitride micro light emitting diode with high brightness and method of manufacturing the same

• US 20060208273A1
• Filed: 08/08/2003
• Published: 09/21/2006
• Est. Priority Date: 08/08/2003
• Status: Active Grant

• Current Assignee: Sang-Kyu Kang
• Original Assignee: Sang-Kyu Kang
• Inventors: Kang, Sang-Kyu
• Granted Patent: US 7,595,511 B2
• Time in Patent Office: Days
• US Class Current: 257/103
• 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
• CPC Class Codes: H01L 33/42 Transparent materials
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating

Abstract

The present invention relates to a nitride micro light emitting diode (LED) with high brightness and a method of manufacturing the same. The present invention provides a nitride micro LED with high brightness and a method of manufacturing the same, wherein a plurality of micro-sized luminous pillars 10 are formed in a substrates, a gap filling material such as SiO₂, Si₃N₄, DBR(ZrO₂/SiO₂ HfO₂/SiO₂), polyamide or the like is filled in gaps between the micro-sized luminous pillars, a top surface 11 of the luminous pillar array and the gap filling material is planarized through a CMP processing, and then a transparent electrode 6 having a large area is formed thereon, so that all the luminous pillars can be driven at the same time. In addition, the present invention provides a nitride micro LED with high brightness in which uniformity in formation of electrodes on the micro-sized luminous pillars array is enhanced by employing a flip-chip structure.

Claims

1. A nitride micro LED (Light Emitting Diode) with high brightness, comprising:

a plurality of micro-sized luminous pillars having an n-type GaN layer formed on a substrate, and active layer formed on the n-type GaN layer, and a p-type GaN layer formed on the active layer;

a gap filling material filled between the luminous pillars to have substantially the same height as the luminous pillars;

a p-type transparent electrode formed on a top surface of the gap filling material and the luminous pillars;

a p-type electrode formed on the p-type transparent electrode; and

an n-type electrode electrically connected to the n-type GaN layer, wherein an array of the luminous pillars is driven at the same time.

2. The nitride micro LED with high brightness according to claim 1, wherein the gap filling material includes at least one selected from SiO₂, Si₃N₄, or a combination thereof, polyamide, and ZrO₂/SiO₂ or HfO₂/SiO₂.

3. The nitride micro LED with high brightness according to claim 2, wherein the gap filling material is formed to have substantially the same height as the luminous pillars through a CMP (Chemical Mechanical Polishing) process.

4. The nitride micro LED with high brightness according to claim 3, wherein a top surface of the p-type GaN layer of the luminous pillars has convex surfaces formed through the CMP process.

5. The nitride micro LED with high brightness according to claim 1, wherein the transparent electrode comprises a combination of oxidized Ni/Au(NiO/Au) or an ITO (Indium Tin Oxide).

6. The nitride micro LED with high brightness according to claim 1, further comprising a pair of DBR (Distributed Bragg Reflectors) layers formed on a top surface of the transparent electrode Hand a bottom surface of the substrate, respectively.

7. The nitride micro LED with high brightness according to claim 1, further comprising an AR (Anti-reflection) layer coated on a top surface of the transparent electrode or a bottom surface of the substrate.

8. The nitride micro LED with high brightness according to claim 1, wherein luminous pillars have side surfaces formed obliquely.

9. The nitride micro LED with high brightness according to claim 8, further comprising a DBR layer made of ZrO₂/SiO₂ or HfO₂/SiO₂ and formed below the gap filling material within gaps between the luminous pillars.

10. A nitride micro LED with high brightness which is mounted through a flip-chip method, comprising:

a sapphire substrate;

a plurality of micro-sized luminous pillars having an n-type GaN layer grown on the sapphire substrate, and active layer formed on the n-type GaN layer, and a p-type GaN layer formed on the active layer;

a gap filling material filled between the luminous pillars to have substantially the same height as the luminous pillars;

a metal electrode formed on a top surface of the gap filling material and the luminous pillars;

a p-type electrode formed on the metal electrode; and

an n-type electrode electronically connected to the n-type GaN layer, wherein an array of the luminous pillars is driven at the same time.

11. A method of manufacturing a nitride micro LED with high brightness having a plurality of micro luminous pillars, comprising:

(a) a step of sequentially growing an n-type GaN layer, an active layer, and a p-type GaN layer on a wafer or substrate;

(b) a step of dry-etching the processed wafer to form the luminous pillars having the n-type GaN layer, the active layer and the p-type GaN layer on the substrate;

(c) a step of depositing a gap filling material in gaps between the luminous pillars;

(d) a step of planarizing a top surface of an array of luminous pillars and a top surface of the gap filling material using a CMP process; and

(e) a step of depositing a transparent electrode on all of the top surfaces of the array of luminous pillars and the gap filling material, depositing a p-type electrode and an n-type electrode at predetermined positions, respectively, and heating the resultant structure.

12. The method of manufacturing a nitride micro LED with high brightness according to claim 11, wherein the step (c) is carried out such that the gaps between the luminous pillars are completely filled with the gap filling material, and wherein the step (d) is carried out such that the top surface of the luminous pillars and the top surface of the gap filling material have the same height as each other.

13. The method of manufacturing a nitride micro LED with high brightness according to claim 11, wherein the step (c) is carried out such that the gaps (between the luminous pillars are completely filled with the gap filling material, and wherein the step (d) is carried out such that the top surface of the p-type GaN layer in the luminous pillars is formed to have convex surfaces.

14. The method of manufacturing a nitride micro LED with high brightness according to claim 11, wherein the gap filling material includes at least one selected from SiO₂, Si₃N₄ or a combination thereof, polyamide, and ZrO₂/SiO₂ or HfO₂/SiO₂.

15. The method of manufacturing a nitride micro LED with high brightness according to claim 11, wherein the transparent electrode comprises a combination of oxidized Ni/Au(NiO/Au) or an ITO (Indium Tin Oxide).

16. The method of manufacturing a nitride micro LED with high brightness according to claim 11, after the step (e), further comprising a step of depositing a pair of DBR (Distributed Bragg Reflectors) layers on a top surface of the transparent electrode and a bottom surface of the substrate.

17. The method of manufacturing a nitride micro LED with high brightness according to claim 11, after the step (e), further comprising a step of coating an AR (Anti-reflection) layer on a top surface of the transparent electrode or a bottom surface of the substrate.

18. The method of manufacturing a nitride micro LED with high brightness according to claim 11, wherein in the step (b), process variables are controlled such that side surfaces of the luminous pillars Ware formed into oblique portions.

19. The method of manufacturing a nitride micro LED with high brightness according to claim 18, between the step (b) and the step (c), further comprising a step of depositing a DBR layer within the gaps between the luminous pillars.

20. A method of manufacturing a nitride micro LED with high brightness having a plurality of micro luminous pillars, comprising:

(a) a step of sequentially growing an n-type GaN layer, an active layer, and a p-type GaN layer on a sapphire wafer or substrate;

(b) a step of dry-etching the processed wafer to form the luminous pillars having the n-type GaN layer, the active layer and the p-type GaN layer on the substrate;

(c) a step of depositing a gap filling material in gaps between the luminous pillars;

(d) a step of planarizing a top surface of an array of luminous pillars and a top surface of the gap filling material musing a CMP process; and

(e) a step of depositing a metal electrode on the overall top surface of the array of luminous pillars, depositing a p-type electrode and an n-type electrode thereon, respectively, and heating the resultant structure.

21. A method of manufacturing a nitride micro LED with high brightness having a plurality of micro luminous pillars, comprising:

(a) a step of growing an n-type GaN buffer layer on a wafer or substrate;

(b) a step of depositing an oxide film on the n-type GaN buffer layer;

(c) a step of wet-etching and patterning the oxide film such that the oxide film has the plurality of pillars and gaps between the plurality of pillars;

(d) a step of sequentially re-growing an n-type GaN layer, an active layer and a p-type GaN layer up to a height of the oxide film pillars using the n-type GaN buffer layer exposed in a bottom surface of the gaps; and

(e) a step of depositing a transparent electrode on the overall top surface of the array of luminous pillars re-grown, depositing a p-type electrode at a predetermined position, depositing an n-type electrode on the n-type GaN layer, and heating the resultant structure.

22. The method of manufacturing a nitride micro LED with high brightness according to claim 21, after the step (e), further comprising a step of depositing a pair of DBR (Distributed Bragg Reflectors) layers on a top surface of the transparent electrode and a bottom surface of the substrate.

23. The method of manufacturing a nitride micro LED with high brightness according to claim 21, after the step (e), further comprising a step of coating an AR (Anti-reflection) layer on a top surface of the transparent electrode or a bottom surface of the substrate.