WO2010064870A2

WO2010064870A2 - Semiconductor light-emitting device

Info

Publication number: WO2010064870A2
Application number: PCT/KR2009/007236
Authority: WO
Inventors: 김창태; 남기연; 이태희
Original assignee: 주식회사 에피밸리
Priority date: 2008-12-04
Filing date: 2009-12-04
Publication date: 2010-06-10
Also published as: JP2012511248A; CN102239577A; KR101000277B1; WO2010064870A3; KR20100064050A

Abstract

The present disclosure relates to a semiconductor light-emitting device, and more particularly, to a semiconductor light-emitting device which generates light through electron-hole recombination, wherein said semiconductor light-emitting device comprises: a first bonding electrode and a second bonding electrode which supply current for the electron-hole recombination; a first branched finger electrode and a second branched finger electrode branched from the first bonding electrode; and a third branched finger electrode which is branched from a third bonding electrode, and which is interposed between the first branched finger electrode and the second branched finger electrode to have a first spacing from the first branched finger electrode and a second spacing from the second branched finger electrode, wherein said second spacing is narrower than the first spacing. The second branched finger electrode is located farther than the first branched finger electrode from the center of the light-emitting device, and the third branched finger electrode is located farther than the second branched finger electrode from the center of the light-emitting device.

Description

Semiconductor light emitting device

The present disclosure relates to a semiconductor light emitting device as a whole, and more particularly, to a semiconductor light emitting device having an electrode structure for current diffusion.

Here, the semiconductor light emitting device refers to a semiconductor optical device that generates light through recombination of electrons and holes, for example, a group III nitride semiconductor light emitting device. The group III nitride semiconductor consists of a compound of Al (x) Ga (y) In (1-x-y) N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ x + y ≦ 1). In addition, GaAs type semiconductor light emitting elements used for red light emission, etc. are mentioned.

This section provides backgound information related to the present disclosure which is not necessarily prior art.

1 is a view illustrating an example of a conventional Group III nitride semiconductor light emitting device, wherein the Group III nitride semiconductor light emitting device is grown on the substrate 100, the buffer layer 200 grown on the substrate 100, and the buffer layer 200. n-type group III nitride semiconductor layer 300, an active layer 400 grown on the n-type group III nitride semiconductor layer 300, p-type group III nitride semiconductor layer 500, p-type 3 grown on the active layer 400 The p-side electrode 600 formed on the group nitride semiconductor layer 500, the p-side bonding pad 700 formed on the p-side electrode 600, the p-type group III nitride semiconductor layer 500 and the active layer 400 are formed. The n-side electrode 800 and the passivation layer 900 are formed on the n-type group III nitride semiconductor layer 300 exposed by mesa etching.

As the substrate 100, a GaN-based substrate is used as the homogeneous substrate, and a sapphire substrate, a SiC substrate, or a Si substrate is used as the heterogeneous substrate. Any substrate may be used as long as the group III nitride semiconductor layer can be grown. When a SiC substrate is used, the n-side electrode 800 may be formed on the SiC substrate side.

Group III nitride semiconductor layers grown on the substrate 100 are mainly grown by MOCVD (organic metal vapor growth method).

The buffer layer 200 is intended to overcome the difference in lattice constant and thermal expansion coefficient between the dissimilar substrate 100 and the group III nitride semiconductor, and US Pat. A technique for growing an AlN buffer layer having a thickness of US Pat. No. 5,290,393 describes Al (x) Ga (1-x) N having a thickness of 10 kPa to 5000 kPa at a temperature of 200 to 900 C on a sapphire substrate. (0 ≦ x <1) A technique for growing a buffer layer is described, and US Patent Publication No. 2006/154454 discloses growing a SiC buffer layer (seed layer) at a temperature of 600 ° C. to 990 ° C., followed by In (x Techniques for growing a Ga (1-x) N (0 <x≤1) layer are described. Preferably, the undoped GaN layer is grown prior to the growth of the n-type Group III nitride semiconductor layer 300, which may be viewed as part of the buffer layer 200 or as part of the n-type Group III nitride semiconductor layer 300. .

In the n-type group III nitride semiconductor layer 300, at least a region (n-type contact layer) in which the n-side electrode 800 is formed is doped with impurities, and the n-type contact layer is preferably made of GaN and doped with Si. . U. S. Patent No. 5,733, 796 describes a technique for doping an n-type contact layer to a desired doping concentration by controlling the mixing ratio of Si and other source materials.

The active layer 400 is a layer that generates photons (light) through recombination of electrons and holes, and is mainly composed of In (x) Ga (1-x) N (0 <x≤1), and one quantum well layer (single quantum wells) or multiple quantum wells.

The p-type III-nitride semiconductor layer 500 is doped with an appropriate impurity such as Mg, and has an p-type conductivity through an activation process. U.S. Patent No. 5,247,533 describes a technique for activating a p-type group III nitride semiconductor layer by electron beam irradiation, and U.S. Patent No. 5,306,662 annealing the p-type Group III nitride semiconductor layer at a temperature of 400 占 폚 or higher. A technique for activating is described, and US Patent Publication No. 2006/157714 discloses a p-type III-nitride semiconductor layer without an activation process by using ammonia and a hydrazine-based source material together as a nitrogen precursor for growth of the p-type III-nitride semiconductor layer. Techniques for having this p-type conductivity have been described.

The p-side electrode 600 is provided to supply a good current to the entire p-type group III nitride semiconductor layer 500. US Patent No. 5,563,422 is formed over almost the entire surface of the p-type group III nitride semiconductor layer. A light-transmitting electrode made of Ni and Au in ohmic contact with the p-type III-nitride semiconductor layer 500 is described. US Pat. No. 6,515,306 discloses n on the p-type III-nitride semiconductor layer. A technique is described in which a type superlattice layer is formed and then a translucent electrode made of indium tin oxide (ITO) is formed thereon.

On the other hand, the p-side electrode 600 may be formed to have a thick thickness so as not to transmit light, that is, to reflect the light toward the substrate side, this technique is referred to as flip chip (flip chip) technology. U. S. Patent No. 6,194, 743 describes a technique relating to an electrode structure including an Ag layer having a thickness of 20 nm or more, a diffusion barrier layer covering the Ag layer, and a bonding layer made of Au and Al covering the diffusion barrier layer.

The p-side bonding pad 700 and the n-side electrode 800 are for supplying current and wire bonding to the outside, and US Patent No. 5,563,422 describes a technique in which the n-side electrode is composed of Ti and Al.

The passivation layer 900 is formed of a material such as silicon dioxide and may be omitted.

Meanwhile, the n-type III-nitride semiconductor layer 300 or the p-type III-nitride semiconductor layer 500 may be composed of a single layer or a plurality of layers, and recently, the substrate 100 may be formed by laser or wet etching. A technique for manufacturing a vertical light emitting device by separating from group III nitride semiconductor layers has been introduced.

2 is a view showing an example of the electrode structure described in U.S. Patent No. 5,563,422, wherein the p-side bonding pad 700 and the n-side electrode 800 are positioned at diagonal corners of the light emitting device to improve current spreading. It is described.

3 is a diagram illustrating an example of an electrode structure described in US Pat. No. 6,307,218. The light emitting device has branches having equal intervals between the p-

side bonding pads

710 and 710 and the n-

side electrodes

810 and 810 as the light emitting device becomes larger. Techniques for improving current spreading with

electrodes

910 and 910 are described.

However, a light emitting device having such an electrode structure has a problem in that current may be concentrated in an area R close to the distance between the p-side bonding pads 710 and the n-side electrodes 810.

On the other hand, when a bonding failure occurs in the wires connected to the p-side bonding pads 710 or the n-side bonding pads 810, there is a problem that the current diffusion of the light emitting device is not smooth.

FIG. 4 is a diagram illustrating an example of a photograph of a semiconductor light emitting device in which wire bonding defects occur. FIG. 4A illustrates a light emitting device in which four wires are normally bonded, and FIG. 4B. Is a picture in which two wires fall, and the light emitting device in which two wires are diagonally bonded emits light, and FIG. 4 (c) shows that the light emitting device in which two wires are dropped and two wires are bonded only in one direction is lighted. It is a photograph to emit. It can be seen that light does not come out evenly due to poor bonding of the wire.

In order to solve this problem, a light emitting device in which two bonding pads are attached to each other has been introduced, but it does not solve the problem of current concentration occurring between the bonding pads located on opposite sides.

This will be described later in the section on Embodiments of the Invention.

This section provides a general summary of the disclosure and is not a comprehensive disclosure of its full scope or all, provided that this is a summary of the disclosure. of its features).

According to one aspect of the present disclosure, in a semiconductor light emitting device that generates light through recombination of electrons and holes, a first bonding supplying a current for recombination of electrons and holes An electrode and a second bonding electrode; A first branch electrode and a second branch electrode extending from the first bonding electrode; A third extending from the second bonding electrode and positioned between the first branch electrode and the second branch electrode with a first gap with respect to the first branch electrode and with a second gap narrower than the first gap with respect to the second branch electrode; Wherein the second branch electrode is located farther from the center of the light emitting device than the first branch electrode, and the third branch electrode is located farther from the center of the light emitting device than the second branch electrode. A light emitting element is provided.

According to an aspect according to the present disclosure, in a semiconductor light emitting device that generates light through recombination of electrons and holes, a first bonding supplying a current for recombination of electrons and holes An electrode and a second bonding electrode, wherein at least one of the first bonding electrode and the second bonding electrode comprises: a first bonding electrode and a second bonding electrode having two bonding pads; A first branch electrode and a second branch electrode extending from the first bonding electrode; A third extending from the second bonding electrode and positioned between the first branch electrode and the second branch electrode with a first gap with respect to the first branch electrode and with a second gap narrower than the first gap with respect to the second branch electrode; There is provided a semiconductor light emitting device comprising a branch electrode.

According to one semiconductor light emitting device according to the present disclosure, it is possible to improve the concentration of current.

According to the other semiconductor light emitting device according to the present disclosure, it is possible to improve the concentration of the current in the case of poor wire bonding.

1 is a view showing an example of a conventional group III nitride semiconductor light emitting device,

2 is a view showing an example of an electrode structure described in US Patent No. 5,563,422;

3 is a view showing an example of an electrode structure described in US Pat. No. 6,307,218;

4 is a diagram illustrating an example of a photograph of a semiconductor light emitting device in which wire bonding defects occur;

5 is a view illustrating an example of an electrode structure of a semiconductor light emitting device according to the present disclosure;

6 illustrates an example of a semiconductor light emitting device according to the present disclosure.

The present disclosure will now be described in detail with reference to the accompanying drawing (s).

5 is a view illustrating an example of an electrode structure of a light emitting device according to the present disclosure. The electrode structure includes

bonding pads

70 and 80 and

branch electrodes

91, 92, 93, and 94.

Current is applied to the

bonding pads

70 and 80. When a current is applied to the

bonding pads

70 and 80, a current may not be evenly spread between the

bonding pads

70 and 80, and a driving region (hereinafter, referred to as a concentrated region R) may occur. Here, the concentrated region R is often located on a straight line distance between the bonding pad 70 and the bonding pad 80, but in the present disclosure, the concentrated region R is the bonding pad 70 and the bonding pad 80. It is not limited to the area | region R1 located on the linear distance between them, and it means the area | region which a current concentrates relatively compared with surrounding. That is, the region R1 may be the concentrated region R with respect to the region R2, and the region R2 may be the concentrated region R with respect to the region R3 (FIG. 5A). Reference). Therefore, the concentrated region R may be formed by relatively changing the distribution of current even in the region R1.

The branch electrode 91 is connected to the bonding pad 70 and is positioned in the concentrated region R. The branch electrode 92 is connected to the bonding pad 80 and is positioned at a distance G1 from the branch electrode 91. The branch electrode 93 is connected to the branch electrode 91 and is positioned at a distance G2 from the branch electrode 92. At this time, the interval G1 is wider than the interval G2 (see FIG. 5B). Accordingly, the concentrated region R may be relaxed or eliminated. The branch electrode 92 and the branch electrode 93 may be sequentially removed from the branch electrode 91 so as to be more advantageous in relaxing or eliminating the concentrated region R. FIG. It is preferred to be arranged as.

Referring to FIG. 5C, the branch electrode 94 is positioned at a gap G3 narrower than the gap G1 with the branch electrode 93, and the gap G3 is preferably narrower than the gap G2. Do. The relationship between the gap G1 formed by the branch electrode 91 and the branch electrode 92 and the gap G2 formed by the branch electrode 92 and the branch electrode 93 is the interval G2 and the gap G3. Because it can be applied to.

FIG. 6 is a diagram illustrating an example of a semiconductor light emitting device according to the present disclosure. The light emitting device includes

bonding pads

70 and 80 and

branch electrodes

91, 92, 93, 94, and 95. Here, the light emitting device is an example of the size of 1mm horizontal, 1mm vertical.

The bonding pad 70 and the bonding pad 80 supply current to emit light in the active layer (see FIG. 1) by recombination of electrons and holes. The bonding pad 70 and the bonding pad 80 are located between both sides of the light emitting element. The bonding pads 70 are formed by attaching two

circular pads

72 and 74 to each other. Meanwhile, in the bonding pad 70, two

pads

72 and 74 which are circular are positioned apart from each other, and the two

pads

72 and 74 are connected to each other by the

branch electrodes

91, 93 and 95. It may be. The bonding pad 80 may also be formed in the same manner as the bonding pad 70. Meanwhile, the

pads

72, 74, 82, and 84 may have various shapes such as ellipses and polygons.

The branch electrode 91 extends from the bonding pad 70 toward the bonding pad 80, which means that the branch electrode 91 is located in the concentrated region R, described with reference to FIG. 5.

The branch electrode 92 is positioned at a distance G1 from the branch electrode 91. For example, the branch electrode 92 extends from the bonding pad 80 toward the bonding pad 70 so that the current can be smoothly spread with the branch electrode 91 at a gap G1 of about 128 μm. It is divided into and is bent and extended in the shape which embraces the branch electrode 91 as a whole.

The branch electrode 93 is positioned at a distance G2 narrower than the distance G1 with the branch electrode 92. For example, the branch electrode 93 is branched from the branch electrode 91 to both sides so that the current spreads smoothly with the branch electrode 92 at an interval G2 of about 89 μm. It is bent and extended in a shape to hold.

The branch electrode 94 is positioned at a distance G3 from the branch electrode 93. The interval G3 is narrower than the interval G1. As described with reference to FIG. 5, the interval G3 is preferably narrower than the interval G2. For example, the branch electrode 94 is divided from both sides of the branch electrode 92 so that the current can be smoothly spread with the branch electrode 93 at an interval G3 of about 80 μm. It is bent and extended in a shape to hold.

The branch electrode 95 may be positioned with respect to the branch electrode 94 at an interval G4 of, for example, about 89 μm, and the interval G4 is wider and narrower than the interval G3 depending on the degree of current concentration. Can also be formed.

The

branch electrodes

92, 93, 94, and 95 have an annular extension e. Through the extension portion e, the current can be spread around, thereby further improving the spread of the current.

Hereinafter, various embodiments of the present disclosure will be described.

(1) A semiconductor light emitting device comprising a plurality of branch electrodes at different intervals. This can improve the concentration of the current.

(2) A semiconductor light emitting element comprising an electrode to which a plurality of wires can be bonded. This can improve the concentration of current even when the wire is poorly bonded to the electrode.

(3) a first bonding electrode and a second bonding electrode for supplying a current for recombination of electrons and holes; A first branch electrode and a second branch electrode extending from the first bonding electrode; A third extending from the second bonding electrode and positioned between the first branch electrode and the second branch electrode with a first gap with respect to the first branch electrode and with a second gap narrower than the first gap with respect to the second branch electrode; A branch electrode; wherein the second branch electrode is located farther from the center of the light emitting device than the first branch electrode, and the third branch electrode is located farther from the center of the light emitting device than the second branch electrode. At least one of the second bonding electrodes is located at the central portion of the light emitting device on one side of the semiconductor light emitting device. Thus, the current can be diffused from the center of the light emitting element to the surroundings.

Claims

In a semiconductor light emitting device that generates light through recombination of electrons and holes,

A first bonding electrode and a second bonding electrode supplying a current for recombination of electrons and holes;

A first branch electrode and a second branch electrode extending from the first bonding electrode;

A third extending from the second bonding electrode and positioned between the first branch electrode and the second branch electrode with a first gap with respect to the first branch electrode and with a second gap narrower than the first gap with respect to the second branch electrode; And a branch electrode;

The second branch electrode is located farther from the center of the light emitting device than the first branch electrode, and the second branch electrode is located farther from the center of the light emitting device than the third branch electrode.
The method according to claim 1,

At least one of the first bonding electrode and the second bonding electrode includes two bonding pads.
The method according to claim 1,

At least one of the first bonding electrode and the second bonding electrode is a semiconductor light emitting device, characterized in that located in the central portion at one side of the light emitting device.
The method according to claim 3,

The first bonding electrode and the second bonding electrode are positioned facing each other.
The method according to claim 1,

The first branch electrode extends toward the second bonding electrode.
The method according to claim 1,

And a fourth branch electrode extending from the second bonding electrode and positioned at a third interval narrower than the second interval with respect to the second branch electrode.
The method according to claim 2,

At least one of the first bonding electrode and the second bonding electrode is located at the central portion of one side of the light emitting device,

The first bonding electrode and the second bonding electrode are located facing each other,

The first branch electrode extends toward the second bonding electrode.
The method according to claim 7,

And a fourth branch electrode extending from the second bonding electrode and positioned at a third interval narrower than the second interval with respect to the second branch electrode.
The method according to claim 8,

The light emitting device is a semiconductor light emitting device, characterized in that the Group III nitride semiconductor light emitting device.
In a semiconductor light emitting device that generates light through recombination of electrons and holes,

A first bonding electrode and a second bonding electrode for supplying a current for recombination of electrons and holes, wherein at least one of the first bonding electrode and the second bonding electrode includes a first bonding electrode and a second bonding pad; Bonding electrodes;

A first branch electrode and a second branch electrode extending from the first bonding electrode;

A third extending from the second bonding electrode and positioned between the first branch electrode and the second branch electrode with a first gap with respect to the first branch electrode and with a second gap narrower than the first gap with respect to the second branch electrode; A branch light emitting device comprising a; electrode.