KR100585918B1 - Electrode of GaN-based semiconductor LED - Google Patents

Electrode of GaN-based semiconductor LED Download PDF

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KR100585918B1
KR100585918B1 KR1020040022010A KR20040022010A KR100585918B1 KR 100585918 B1 KR100585918 B1 KR 100585918B1 KR 1020040022010 A KR1020040022010 A KR 1020040022010A KR 20040022010 A KR20040022010 A KR 20040022010A KR 100585918 B1 KR100585918 B1 KR 100585918B1
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electrode
layer
type
light emitting
nitride
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KR20050096582A (en
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이브라크로와
이영주
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서울옵토디바이스주식회사
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    • H—ELECTRICITY
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    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/36—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/0004—Devices characterised by their operation
    • H01L33/0008—Devices characterised by their operation having p-n or hi-lo junctions
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/10—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a light reflecting structure, e.g. semiconductor Bragg reflector
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/14—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure
    • H01L33/145—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure with a current-blocking structure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/36—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the electrodes
    • H01L33/40—Materials therefor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2933/00—Details relating to devices covered by the group H01L33/00 but not provided for in its subgroups
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    • H01L2933/0016—Processes relating to electrodes

Abstract

본 발명은 질화물계 반도체 발광소자에 관한 것으로 특히, 전극의 구조를 개선하여 접촉저항을 감소시키고, 광적출을 향상시킬 수 있는 질화물계 반도체 발광소자의 피형 전극에 관한 것이다. 본 발명에 따른 질화물계 반도체소자의 p형 전극은 기판 상에 n형 접촉층, 활성층 및 p형 접촉층이 순차적으로 형성되고 상기 n형 접촉층 및 상기 p형 접촉층의 소정 부분 상에 n형 전극 및 p형 전극이 형성되는 질화물계 반도체 발광소자에 있어서, 전극층/확산방지층/반사층이 순차적으로 적층된 다층전극을 포함하는 것을 특징으로 한다. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nitride semiconductor light emitting device, and more particularly, to an electrode of a nitride based semiconductor light emitting device which can improve the structure of an electrode to reduce contact resistance and improve light extraction. In the p-type electrode of the nitride semiconductor device according to the present invention, the n-type contact layer, the active layer and the p-type contact layer are sequentially formed on the substrate, and the n-type contact layer and the n-type contact portion on the predetermined portion of the p-type contact layer. A nitride semiconductor light emitting device in which an electrode and a p-type electrode are formed, characterized in that it comprises a multilayer electrode in which an electrode layer / diffusion prevention layer / reflective layer is sequentially stacked.

따라서, 본 발명의 질화물계 반도체 발광소자는 p형 접촉층 상의 일부에 전극층/확산방지층/반사층을 적층하여 일정 두께를 갖는 다층전극으로 접촉저항을 낮추어 소자의 구동 전압이 낮아져 고출력 소자 제작을 용이하게 하며, 외부양자효율을 증가시켜 고효율 소자를 제작할 수 있는 이점이 있다. Therefore, the nitride semiconductor light emitting device of the present invention is a multilayer electrode having a predetermined thickness by stacking an electrode layer / diffusion prevention layer / reflective layer on a portion of the p-type contact layer to lower the contact resistance, thereby lowering the driving voltage of the device, thereby facilitating the manufacture of a high output device. In addition, there is an advantage to manufacture a high efficiency device by increasing the external quantum efficiency.

확산방지막, 외부양자효율, 접촉저항, 질화물계 반도체소자, 광적출Diffusion barrier, external quantum efficiency, contact resistance, nitride semiconductor device, light extraction

Description

질화물계 반도체소자의 전극{Electrode of GaN-based semiconductor LED}Electrode of nitride-based semiconductor device {Electrode of GaN-based semiconductor LED}

도 1은 일반적인 질화물계 반도체 발광소자를 개략적으로 도시하는 단면도.1 is a cross-sectional view schematically showing a general nitride semiconductor light emitting device.

도 2는 일반적인 질화물계 반도체 발광소자를 개략적으로 도시하는 평면도.2 is a plan view schematically showing a general nitride semiconductor light emitting device.

도 3은 본 발명의 실시 예에 따른 질화물계 반도체 발광소자를 개략적으로 도시하는 단면도.3 is a cross-sectional view schematically showing a nitride-based semiconductor light emitting device according to an embodiment of the present invention.

도 4는 본 발명의 실시 예에 따른 질화물계 반도체 발광소자를 개략적으로 도시하는 평면도.4 is a plan view schematically showing a nitride-based semiconductor light emitting device according to an embodiment of the present invention.

도 5는 본 발명의 실시 예에 따른 질화물계 반도체 발광소자의 광자적출 개념도. 5 is a conceptual diagram of photon extraction of a nitride-based semiconductor light emitting device according to an exemplary embodiment of the present invention.

<도면의 주요 기호에 대한 상세한 설명><Detailed Description of Main Symbols in Drawings>

31 : 기판 33 : n형 접촉층31 substrate 33 n-type contact layer

35 : 활성층 37 : p형 접촉층35 active layer 37 p-type contact layer

39 : 전극층 40 : 확산방지층39: electrode layer 40: diffusion barrier layer

41 : 반사층 45 : n형 전극41: reflective layer 45: n-type electrode

본 발명은 질화물계 반도체 발광소자에 관한 것으로 특히, 전극의 구조를 개선하여 접촉저항을 감소시키고, 광적출을 향상시킬 수 있는 질화물계 반도체 발광소자의 전극에 관한 것이다. The present invention relates to a nitride-based semiconductor light emitting device, and more particularly, to an electrode of a nitride-based semiconductor light emitting device that can improve the structure of the electrode to reduce the contact resistance, and improve light extraction.

대표적인 질화물계 반도체인 질화갈륨(GaN)은 에너지 밴드갭이 3.4 eV로 매우 크고, 높은 전자이동도를 가지고 있기 때문에 고출력 소자에 사용할 수 있다는 장점 및 광대역 밴드갭을 가지고 있으므로 밴드갭 조절에 의해 가시영역 및 자외 영역의 발광소자를 제작할 수 있다는 커다란 장점을 가지고 있다. Gallium nitride (GaN), a typical nitride-based semiconductor, has an energy band gap of 3.4 eV, which is very large, and has high electron mobility, so it can be used for high-power devices and broadband band gap. And it has a great advantage that it can manufacture a light emitting device in the ultraviolet region.

그리고, 통상적으로 가시영역 발광다이오드 재료로 사용하는 GaP는 간접천이형 밴드갭을 가지고 있어 내부양자효율이 낮은 반면 GaN의 경우 직접천이형 밴드갭을 가지고 있으므로 상대적으로 높은 내부양자효율을 얻을 수 있다. In addition, GaP, which is generally used as a visible light emitting diode material, has an indirect transition type bandgap to have low internal quantum efficiency, while GaN has a direct transition type bandgap to obtain a relatively high internal quantum efficiency.

그러므로 청색 발광다이오드(Light Emitting Diode ; LED), 단파장 레이저 다이오드, 자외선 검출기(Ultra violet Detector) 등과 같은 광소자에 응용 될 뿐만 아니라 고전자 이동도 트랜지스터(High Electron Mobility Transistor ; HEMT), 이종접합트랜지스터(Hetero-junction Bipolar Transistor ; HBT) 등과 같은 고온 고출력 소자에도 많이 사용되고 있다. Therefore, it is not only applied to optical devices such as blue light emitting diodes (LEDs), short wavelength laser diodes, and ultra violet detectors, but also high electron mobility transistors (HEMTs) and heterojunction transistors. It is also widely used in high-temperature, high-power devices such as heterojunction bipolar transistors (HBTs).

질화갈륨 발광다이오드의 발광원리는 외부에서 인가되는 전계가 n형 질화갈륨에 유입되면 전자가 AlGaN/InGaN양자우물 쪽으로 이동하고 역시 p형 질화갈륨에서는 정공이 이동하여 양자우물에서 재결합 후 InGaN 밴드갭에 해당하는 빛을 발광하여 p형 질화갈륨을 통하여 발광다이오드 상단으로 발광하거나 측면 및 하부 기판을 통해 외부로 발광하게 된다. The luminescence principle of the gallium nitride light emitting diode is that when an external electric field flows into the n-type gallium nitride, electrons move toward the AlGaN / InGaN quantum well, and in p-type gallium nitride, holes move and recombine in the quantum well. The corresponding light is emitted to emit light to the top of the light emitting diode through the p-type gallium nitride, or to the outside through the side and bottom substrate.

일반적인 질화물계 반도체 발광소자는 도 1에 도시된 바와 같이 사파이어 기판(11)의 일면 상에 n형 접촉층(13), 활성층(15) 및 p형 접촉층(17)이 순차적으로 적층되고, 상기 p형 접촉층(17) 및 활성층(15)의 소정 부분이 제거되어, 그 제거로 노출된 n형 접촉층(13) 상의 각각 소정 부분에 n형 전극(21)이 형성되고, 상기 p형 접촉층(17) 상의 전면을 덮는 투명전극(19)과 상기 투명전극(19) 상의 소정 부분에 p형 전극(23)이 형성된 구조를 갖는다. In the general nitride based semiconductor light emitting device, as shown in FIG. 1, an n-type contact layer 13, an active layer 15, and a p-type contact layer 17 are sequentially stacked on one surface of the sapphire substrate 11. Predetermined portions of the p-type contact layer 17 and the active layer 15 are removed, and n-type electrodes 21 are formed at predetermined portions on the n-type contact layer 13 exposed by the removal, and the p-type contact The transparent electrode 19 covering the entire surface of the layer 17 and the p-type electrode 23 are formed in a predetermined portion on the transparent electrode 19.

이렇게 형성된 소자의 평면도가 도 2로 n형 및 p형 전극(21)(23)은 패키지 조립시 진행되는 전도성 와이어 조립 및 전류 확산 효과 등의 이유로 발광다이오드의 양 끝단에 위치하고, 질화물 청색 발광다이오드는 통상적으로 부도체인 사파이어를 기판으로 하여 성장되므로 발광다이오드 상단에 n형 및 p형 전극(21)(23)이 모두 형성되는 두 상부 전극구조를 갖게된다. As shown in FIG. 2, the n-type and p-type electrodes 21 and 23 are positioned at both ends of the light emitting diodes due to conductive wire assembly and current spreading effect. Typically, since the substrate is grown using a sapphire, which is a non-conductor, it has two upper electrode structures in which both the n-type and p-type electrodes 21 and 23 are formed on the top of the light emitting diode.

또한, p형 질화갈륨은 낮은 p형 운반자 농도와 같은 이유로 말미암아 높은 저항을 갖게된다. 따라서, 통상적인 발광다이오드 제작시 p형 질화갈륨 전면에 낮은 접촉저항을 갖고 일정 광 투과성을 갖는 투명 전극을 형성할 수밖에 없는 실정이다. In addition, p-type gallium nitride has high resistance for the same reasons as low p-type carrier concentrations. Therefore, when manufacturing a conventional light emitting diode, there is no choice but to form a transparent electrode having low contact resistance and constant light transmittance on the entire surface of the p-type gallium nitride.

이와 같은 p형 전극물질은 높은 투광성을 갖도록 높은 일함수를 갖는 Ni, Pt, Pd, Au, Ru, W, Co, Re 및 Rh 등의 물질을 수십에서 수백 Å의 낮은 두께로 형성하여 얻는다. 하지만 이렇게 전면에 형성된 p형 전극은 현재까지 보고된 바에 의하면 10-3 Ω㎠ 정도의 접촉저항 및 청색 파장에서 약 80 % 정도의 광 투과성을 나타낼 수 밖에 없다. Such a p-type electrode material is obtained by forming a material having a high work function such as Ni, Pt, Pd, Au, Ru, W, Co, Re, and Rh with a low thickness of several tens to several hundreds of microseconds. However, the p-type electrode formed on the front surface has been reported so far to show a contact resistance of about 10-3 μm 2 and light transmittance of about 80% at a blue wavelength.

접촉저항을 높이기 위하여 p형 금속 전극의 두께를 증가시킬 경우는 반대로 양자우물에서 발생된 광자가 두꺼운 p형 전극을 통해 외부로 빠져나오지 못하게되므로 광 투과율이 현저히 저하되는 결과를 초래하게된다. Increasing the thickness of the p-type metal electrode in order to increase the contact resistance, on the contrary, since the photons generated in the quantum well cannot escape through the thick p-type electrode, the light transmittance is significantly reduced.

이와 같은 문제로 두꺼운 p형 전극 및 광 반사층을 갖고 역전된 형태로 조립하는 플립칩 형태의 칩이 구상되어 많은 연구가 진행되고 있다. 역전된 발광소자, 즉, 플립칩의 경우에는 두꺼운 p형 전극으로 말미암아 낮은 접촉저항을 나타내고 양자우물에서 발생된 광자가 p형 전극에 반사되어 통상적으로 사용되는 사파이어 및 탄화규소 기판을 통해 외부로 빠져나오게 된다.  Due to such a problem, a lot of researches have been conducted since a chip of a flip chip type having a thick p-type electrode and a light reflecting layer and assembled in an inverted form is envisioned. Inverted light emitting devices, i.e. flip-chips, exhibit low contact resistance due to thick p-type electrodes, and photons generated from quantum wells are reflected by the p-type electrodes and fall outside through commonly used sapphire and silicon carbide substrates. Come out.

그러나 이와 같은 좋은 장점이 있음에도 불구하고 플립칩 제작 및 조립 시 낮은 수율 문제와 제조원가의 상승으로 소자 제작 시 제약이 따르게된다. 때문에 플립칩 형태의 발광다이오드는 한정된 소자에만 부분적으로 생산이 진행되고 있는 실정이다.However, despite this good advantage, low chip yield and manufacturing cost increase in flip chip fabrication and assembly, resulting in restrictions in device fabrication. As a result, a light emitting diode of a flip chip type is partially produced in a limited device.

따라서, 본 발명의 목적은 질화물계 반도체소자의 전극 형성시 접촉 저항을 감소시키고, 광 적출을 향상시킬 수 있는 질화물계 반도체소자의 전극을 제공함에 있다.Accordingly, it is an object of the present invention to provide an electrode of a nitride-based semiconductor device capable of reducing contact resistance and improving light extraction when forming an electrode of a nitride-based semiconductor device.

상기 목적을 달성하기 위한 본 발명에 따른 질화물계 반도체소자의 p형 전극은 기판 상에 n형 접촉층, 활성층 및 p형 접촉층이 순차적으로 형성되고 상기 n형 접촉층 및 상기 p형 접촉층의 소정 부분 상에 n형 전극 및 p형 전극이 형성되는 질화물계 반도체 발광소자에 있어서, 전극층/확산방지층/반사층이 순차적으로 적층된 다층 전극을 포함하는 것을 특징으로 한다. The p-type electrode of the nitride-based semiconductor device according to the present invention for achieving the above object is an n-type contact layer, an active layer and a p-type contact layer is sequentially formed on the substrate and the n-type contact layer and the p-type contact layer A nitride semiconductor light emitting device in which an n-type electrode and a p-type electrode are formed on a predetermined portion, characterized in that it comprises a multilayer electrode in which electrode layers / diffusion prevention layers / reflective layers are sequentially stacked.

이하, 첨부된 도면을 참조하여 본 발명을 상세히 설명한다. Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

도 3 및 도 4는 본 발명에 따른 질화물계 반도체소자를 개략적으로 도시하는 단면도 및 평면도이고, 도 5는 본 발명에 따른 질화물계 반도체소자의 광자 적출 개념도이다. 3 and 4 are cross-sectional views and plan views schematically illustrating a nitride semiconductor device according to the present invention, and FIG. 5 is a conceptual diagram of photon extraction of the nitride semiconductor device according to the present invention.

본 발명은 접촉저항을 저하시키고 높은 광 투과율을 위하여 도 3에 도시된 바와 같이 p형 질화갈륨 표면에 전극층, 확산방지층, 반사층이 순차적으로 적층된 다층 전극(42)과 전류확산층 구조를 갖는다. 이때, 상기 다층 전극(42)은 두 개 이상일 수 있다.The present invention has a multi-layer electrode 42 and a current diffusion layer structure in which an electrode layer, a diffusion barrier layer, and a reflective layer are sequentially stacked on a p-type gallium nitride surface as shown in FIG. 3 to decrease contact resistance and high light transmittance. In this case, two or more multilayer electrodes 42 may be provided.

이와 같은 구조를 형성하기 위해 사파이어(Al2O3), 질화알루미늄(AlN), 질화갈륨(GaN), 탄화규소(SiC), 셀레늄아연(ZnSe), 또는 질화붕소(BN) 등을 이용한 기판(31) 상에 n형 접촉층(33), 활성층(35) 그리고 p형 접촉층(37)이 순차적으로 적층되어 있고, 상기 p형 접촉층(37) 및 활성층(35)의 소정 부분이 제거되어, 그 제거로 노출된 n형 접촉층(33)에 n형 전극(45)을 형성한다. A substrate using sapphire (Al 2 O 3 ), aluminum nitride (AlN), gallium nitride (GaN), silicon carbide (SiC), selenium zinc (ZnSe), or boron nitride (BN) to form such a structure ( 31, the n-type contact layer 33, the active layer 35 and the p-type contact layer 37 are sequentially stacked, and predetermined portions of the p-type contact layer 37 and the active layer 35 are removed. The n-type electrode 45 is formed on the n-type contact layer 33 exposed by the removal.

그리고, 상기 p형 접촉층(37) 상에 Ni/Au 또는 Ru/Ni 등을 이용하여 접촉전극(39)을 형성하고, 상기 전극층(39) 상에 ITO(Indium Tin Oxide) 또는 IZO(Indium Zinc Oxide) 등의 확산방지층(40)과, 상기 확산방지층(40) 상에 Al 또는 Ag 등의 반사층(41)을 적층하여 다층 전극(42)을 형성한다. 상기 다층 전극(42)은 p형 접촉층(37) 상의 전면에 형성되지 않고 서로 분리되어 부분적으로만 형성된다. 그런 다음에, 상기 다층 전극(42)을 덮는 전류 확산층(43)과 상기 전류 확산층(43)의 소정 부분 상에 p형 전극(47)을 형성한다. 통상적으로 ITO 및 IZO의 경우 가시영역에서 약 90 % 이상의 광투과율을 나타내는 것으로 알려져 있고, 전도성 향상을 위해 상기 ITO 또는 IZO에 소량의 불순물을 첨가 할 수도 있다. In addition, a contact electrode 39 is formed on the p-type contact layer 37 using Ni / Au or Ru / Ni, and indium tin oxide (ITO) or indium zinc (IZO) on the electrode layer 39. A multilayer electrode 42 is formed by stacking a diffusion barrier layer 40 such as oxide) and a reflective layer 41 such as Al or Ag on the diffusion barrier layer 40. The multilayer electrode 42 is not formed on the front surface on the p-type contact layer 37 but is formed to be separated from each other only partially. Then, the p-type electrode 47 is formed on the current spreading layer 43 covering the multilayer electrode 42 and a predetermined portion of the current spreading layer 43. In general, ITO and IZO are known to exhibit light transmittance of about 90% or more in the visible region, and a small amount of impurities may be added to the ITO or IZO to improve conductivity.

상기 다층 전극(42)을 부분적으로 형성하기 위해서는 p형 접촉층(37) 전면에 전극층(39)/확산방지층(40)/반사층(41)을 순차적으로 적층한 후, 상기 다층 전극(42)을 패터닝한다. In order to partially form the multilayer electrode 42, the electrode layer 39, the diffusion barrier layer 40, and the reflection layer 41 are sequentially stacked on the entire surface of the p-type contact layer 37, and then the multilayer electrode 42 is formed. Pattern.

도 4는 상술한 본 발명의 실시 예에 따른 질화갈륨계 발광다이오드의 평면도로서, 일정 두께를 갖는 p형 전극(47) 및 다층 전극(42)의 반사층(41)은 발광다이오드의 소자 내부에서 발생된 광자의 외부적출을 방해하는 요소이므로 p형 질화갈륨 표면의 소정 영역에만 위치하게된다. 4 is a plan view of a gallium nitride-based light emitting diode according to an embodiment of the present invention, the p-type electrode 47 and the reflective layer 41 of the multi-layer electrode 42 having a predetermined thickness is generated inside the device of the light emitting diode. Since it prevents the external extraction of the photons, it is located only in a predetermined region of the p-type gallium nitride surface.

도 5는 본 발명에 따른 질화물계 발광다이오드의 광자 적출개념도로서, 외부에서 인가되는 전계가 n형 질화갈륨에 유입되면 전자가 AlGaN/InGaN로 구성된 양자우물 쪽으로 이동하고 역시 p형 질화갈륨에서는 정공이 이동하여 양자우물에서 재결합한 후 InGaN 밴드갭에 해당하는 광자가 형성된다. 광자는 p형 전극이 형성되어 있지 않은 부분에서는 90 % 이상 높은 투과율을 갖는 전류 확산층(43)을 통해 외부로 빠져나올 수 있다. 그리고, p형 전극과 만나는 광자들은 높은 반사율을 갖는 전극에 반사되고 다시 GaN와 사파이어 기판 사이의 굴절률 차이에 의해 계면에서 일부 반사되는 광자들은 재반사를 일으켜 외부로 빠져나오거나 사파이어로 투과된 광자 역시 측면을 통해 발광 다이오드 외부로 빠져나오거나 전면은 전류 확산층(43)을 통해 빠져나오게 되므로 외부 양자효율이 종래 발광다이오드에 비해 약 20 % 이상 증가 된다. 5 is a conceptual diagram of photon extraction of a nitride-based light emitting diode according to the present invention. When an electric field applied from the outside flows into n-type gallium nitride, electrons move toward a quantum well composed of AlGaN / InGaN, and holes are also formed in p-type gallium nitride. After moving and recombining in the quantum well, photons corresponding to the InGaN bandgap are formed. The photons may be emitted to the outside through the current diffusion layer 43 having a high transmittance of 90% or more in the portion where the p-type electrode is not formed. Photons that meet the p-type electrode are reflected by the electrode with high reflectivity, and photons that are partially reflected at the interface due to the difference in refractive index between GaN and the sapphire substrate are re-reflected, and the photons transmitted to the outside or transmitted by sapphire are also Since the light exits to the outside of the light emitting diode through the side surface or the front surface of the light emitting diode through the current diffusion layer 43, the external quantum efficiency is increased by about 20% or more compared with the conventional light emitting diode.

따라서, 본 발명의 질화물계 반도체 발광소자는 전극층/확산방지층/반사층을 적층하여 일정 두께를 갖는 다층 전극 형성함으로서 접촉저항을 낮추어 소자의 구동 전압이 낮아져 고출력 소자 제작을 용이하게 하며, 외부양자효율을 증가시켜 고효율 소자를 제작할 수 있는 이점이 있다. Therefore, the nitride-based semiconductor light emitting device of the present invention forms a multilayer electrode having a predetermined thickness by stacking electrode layers / diffusion prevention layers / reflective layers to lower the contact resistance, thereby lowering the driving voltage of the device, thereby facilitating the manufacture of high output devices, and increasing external quantum efficiency. There is an advantage that can be increased to manufacture a high efficiency device.

Claims (5)

기판 상에 n형 접촉층, 활성층 및 p형 접촉층이 순차적으로 형성되고 상기 n형 접촉층 및 상기 p형 접촉층의 소정 부분 상에 n형 전극 및 p형 전극이 형성되는 질화물계 반도체 발광소자의 전극 구조에 있어서,A nitride based semiconductor light emitting device in which an n-type contact layer, an active layer, and a p-type contact layer are sequentially formed on a substrate, and an n-type electrode and a p-type electrode are formed on a portion of the n-type contact layer and the p-type contact layer. In the electrode structure of, 전극층/확산방지층/반사층이 순차적으로 적층된 것을 특징으로 하는 질화물계 반도체소자의 전극 구조.Electrode structure of the nitride-based semiconductor device, characterized in that the electrode layer / diffusion prevention layer / reflection layer are sequentially stacked. 청구항 1에 있어서, The method according to claim 1, 상기 전극층/확산방지층/반사층은 두 개 이상이 상기 발광소자 상에 이격 형성된 것을 특징으로 하는 질화물계 반도체소자의 전극 구조.Electrode structure of the nitride-based semiconductor device, characterized in that two or more electrode layer / diffusion prevention layer / reflection layer formed on the light emitting device spaced apart. 청구항 1에 있어서, The method according to claim 1, 상기 전극층은 Ni/Au 또는 Ru/Ni을 포함하는 것을 특징으로 하는 질화물계 반도체소자의 전극 구조.The electrode layer is an electrode structure of the nitride-based semiconductor device, characterized in that containing Ni / Au or Ru / Ni. 청구항 1에 있어서, The method according to claim 1, 상기 확산방지층은 ITO(Indium Tin Oxide) 또는 IZO(Indium Zinc Oxide)을 포함하는 것을 특징으로 하는 질화물계 반도체소자의 전극 구조.The diffusion barrier layer is an electrode structure of a nitride-based semiconductor device, characterized in that it comprises indium tin oxide (ITO) or indium zinc oxide (IZO). 청구항 1에 있어서, The method according to claim 1, 상기 반사층은 Al 또는 Ag을 포함하는 것을 특징으로 하는 질화물계 반도체소자의 전극 구조.The reflective layer is an electrode structure of a nitride-based semiconductor device, characterized in that containing Al or Ag.
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