KR101009653B1 - Group III nitride semiconductor light emitting device - Google Patents

Abstract

The present disclosure relates to a group III nitride semiconductor light emitting device, and in particular, a substrate having a scattering region formed therein, wherein the scattering region is formed such that the substrate is transformed inside the substrate by a laser to have various scattering angles. Board; And a first group III nitride semiconductor layer formed on the substrate and having a first conductivity, a second group III nitride semiconductor layer formed on the first group III nitride semiconductor layer and having a second conductivity different from the first conductivity, and And a plurality of Group III nitride semiconductor layers positioned between the Group 1 III nitride semiconductor layers and the second Group III nitride semiconductor layers and having an active layer that generates light by recombination of electrons and holes. It relates to a nitride semiconductor light emitting device.

Group III nitride, semiconductor, light emitting device, scattering, substrate, sapphire, laser

Description

Group III nitride semiconductor light emitting device {III-NITRIDE SEMICONDUCTOR LIGHT EMITTING DEVICE}

The present disclosure relates to a group III nitride semiconductor light emitting device as a whole, and more particularly, to a group III nitride semiconductor light emitting device in which a scattering region is formed inside a substrate to improve light extraction efficiency. Here, the group III nitride semiconductor light emitting device has a compound semiconductor layer of Al (x) Ga (y) In (1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ x + y ≦ 1). Means a light emitting device, such as a light emitting diode comprising a, and does not exclude the inclusion of a material consisting of elements of other groups such as SiC, SiN, SiCN, CN or a semiconductor layer of these materials.

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, the 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. good.

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 at a temperature of 400 DEG C or higher to provide a p-type group III nitride semiconductor layer. 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 growing 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.

FIG. 2 is a view showing an example of the semiconductor light emitting device described in US Patent No. 6,657,236, which forms a rough surface 310 having a different refractive index in the group III nitride semiconductor layer 300 to scatter light outside Techniques for improving quantum efficiency have been described.

3 is a view showing another example of the semiconductor light emitting device described in US Patent No. 6,657,236, which forms a material layer 120 (SiO ₂ or nitride layer) having a different refractive index on the substrate 100 on which the protrusions 110 are formed. Then, a technique of increasing the external quantum efficiency by forming the group III nitride semiconductor layer 300 thereon is described.

FIG. 4 is a view showing an example of a method of manufacturing a semiconductor light emitting device disclosed in US Patent Publication No. 2008/121906. In separating the light emitting devices into individual chips, a groove is first formed on the substrate 100 using a laser. A technique is described that facilitates separation into individual chips by forming 130 and then further forming grooves 140. In the formation of the groove 140, the laser is irradiated to the substrate 100 from the opposite side of the substrate 100, that is, the side where the groove 130 is formed, and by matching the focus of the laser to the area where the groove 140 is formed 140 can be formed.

FIG. 5 is a view showing an example of a method for manufacturing a semiconductor light emitting device disclosed in Japanese Patent Laid-Open No. 11-163403. A laser is irradiated to form a processing deformed layer 110, and then a groove 130 is formed. To separate the chips into individual chips.

This will be described later in the Specification for Implementation of the Invention.

SUMMARY OF THE INVENTION Herein, a general summary of the present disclosure is provided, which should not be construed as limiting the scope of the present disclosure. of its features).

According to one aspect of the disclosure, a substrate having a scattering region formed therein, wherein the scattering region is transformed into a substrate in a substrate by means of a laser, A substrate formed to have a catering angle; And a first group III nitride semiconductor layer formed on the substrate and having a first conductivity, a second group III nitride semiconductor layer formed on the first group III nitride semiconductor layer and having a second conductivity different from the first conductivity, and And a plurality of Group III nitride semiconductor layers positioned between the Group 1 III nitride semiconductor layers and the second Group III nitride semiconductor layers and having an active layer that generates light by recombination of electrons and holes. A nitride semiconductor light emitting device is provided.

This will be described later in the Specification for Implementation of the Invention.

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

6 is a diagram illustrating an example of a group III nitride semiconductor light emitting device according to the present disclosure, in which the group III nitride semiconductor light emitting device is epitaxially grown on the substrate 10, the substrate 10, and the buffer layer 20. On the n-type group III nitride semiconductor layer 30 epitaxially grown on the n-type group III nitride semiconductor layer 30, the active layer 40 epitaxially generates light by recombination of electrons and holes, and on the active layer 40 An epitaxially grown p-type group III nitride semiconductor layer 50 and a scattering region 90.

The substrate 10 may be made of a sapphire substrate.

FIG. 7 is a diagram illustrating an example of a substrate included in a group III nitride semiconductor light emitting device according to the present disclosure. A scattering zone 90 is formed in the substrate 10 to form an active layer 40. Scatters the light generated by the &lt; RTI ID = 0.0 &gt; The scattering region 90 is formed by deforming the substrate 10 (eg, sapphire is transformed in the case of a sapphire substrate) inside the substrate 10. Thus, the scattering region 90 may vary in size or shape, and one scattering region 90 may provide various scattering angles. On the other hand, the scattering region 90 may be continuously formed transversely or longitudinally between the upper and lower surfaces of the substrate 10. P represents an example of the light path.

FIG. 8 is a diagram illustrating another example of a substrate included in a group III nitride semiconductor light emitting device according to the present disclosure. A plurality of scattering regions 90 may be formed, and the distribution of scattering regions 90 may be Distribution of scattering zones may be irregular and may be made while maintaining a predetermined interval. In order to make the distribution of the scattering regions 90 even, it is preferable that the scattering regions 90 are formed while maintaining a predetermined interval. P represents another example of the light path.

9 is a view showing another example of a substrate provided in the group III nitride semiconductor light emitting device according to the present disclosure, wherein the scattering region 90 is formed transversely across the upper and lower surfaces of the substrate 10 and is continuously formed. The scattering regions 90 are formed while maintaining a predetermined interval.

Hereinafter, a method of manufacturing a group III nitride semiconductor light emitting device according to the present disclosure will be described using an sapphire substrate as an example.

10 is a view showing an example of a method of manufacturing a group III nitride semiconductor light emitting device according to the present disclosure.

First, the board | substrate 10 is prepared (refer FIG. 10 (a)).

Next, the scattering area | region 90 is formed by irradiating the laser 88 to the inside A of the board | substrate 10 from the upper surface 12 side of the board | substrate 10 (refer FIG.10 (b)). Irradiation of the laser 88 may be performed on the lower surface 14 side of the substrate 10. The size, shape, and the like of the scattering region 90 may vary depending on the irradiation conditions of the laser 88. The scattering region 90 may be moved by moving the substrate 10 or the laser 88 while the laser 88 is irradiated. ) May be continuously formed transversely or longitudinally between the upper surface 12 and the lower surface 14 of the substrate 10 (see (c) of FIG. 10). Irradiation conditions of the laser 88 will be described in detail in the following experimental example. At this time, the focal point of the laser 88 is located in the interior A of the substrate 10. On the other hand, when the light emitting device is divided into individual light emitting devices to reduce the thickness of the substrate 10 to facilitate the separation to the individual light emitting devices, when polishing the lower surface 14 of the substrate 10, scattering area 90 In order to prevent () from being damaged or lost, the focus of the laser 88 is preferably located on the upper surface 12 side in the interior A of the substrate 10.

Next, the buffer layer 20, the n-type Group III nitride semiconductor layer 30, the active layer 40, and the p-type Group III nitride semiconductor layer 50 are grown on the upper surface 12 of the substrate 10 (Fig. (D) of 10). Here, the scattering region 90 is formed on the upper surface 12 of the substrate 10 by the buffer layer 20, the n-type Group III nitride semiconductor layer 30, the active layer 40, and the p-type Group III nitride semiconductor layer. It may be made after growing (50).

Experimental Example

FIG. 11 shows a micrograph of the substrate processed according to the present experimental example as seen from above, and the scattering region 90 deformed by the laser is visible inside the substrate 10. No surface damage of the substrate 10 was found.

FIG. 12 illustrates a micrograph of the scattering regions viewed from above according to the present experimental example, wherein the scattering regions 90 are formed on the substrate 10 at intervals of 300 μm. can see.

FIG. 13 is a photograph viewed from above of a group III nitride semiconductor light emitting device including a substrate processed according to the present experimental example, and it is seen that much light is emitted from the scattering region 90 formed inside the substrate 10 (see FIG. 6). Can be.

Substrate 10 is a flat substrate made of sapphire, a thickness of 400㎛ and 2inch diameter was used.

The laser 88 is a type of UV pulse laser, has a wavelength of 532 nm, has a pulse of 7 ns, and uses a micro spot lens with a focal point of the laser 88 at a depth of 130 μm from the upper surface 12 of the substrate 10. The substrate 10 was processed. On the other hand, the laser 88 was irradiated so that the interval of the scattering regions 90 became 300 mu m. (See Figures 10-12)

Various embodiments of the present disclosure will be described below.

(1) A scattering region is a group III nitride semiconductor light emitting element, wherein the substrate is deformed by a laser.

(2) A group III nitride semiconductor light emitting element, wherein the scattering region is formed continuously across the substrate.

(3) A group III nitride semiconductor light emitting element, characterized in that a plurality of scattering regions are formed on a substrate.

(4) A group III nitride semiconductor light emitting element, wherein the substrate is made of sapphire.

(5) A group III nitride semiconductor light emitting element, wherein the scattering region is formed above the inside of the substrate.

(6) A group III nitride semiconductor light emitting element, wherein the substrate is made of sapphire, and the scattering region is a region where the substrate is deformed by a laser, and is formed on the inside of the substrate.

According to one group III nitride semiconductor light emitting device according to the present disclosure, it is possible to improve the light extraction efficiency of the light emitting device.

In addition, according to another group III nitride semiconductor light emitting device according to the present disclosure, it is possible to form a scattering region without being limited in the order of the steps.

In addition, according to another group III nitride semiconductor light emitting device according to the present disclosure, it is possible to improve the light extraction efficiency of the light emitting device through various scattering angles.

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 a semiconductor light emitting device described in US Patent No. 6,657,236

3 is a view showing another example of the semiconductor light emitting device described in US Patent No. 6,657,236;

4 is a view showing an example of a method of manufacturing a semiconductor light emitting device disclosed in US Patent Publication No. 2008/121906;

5 is a view showing an example of a method of manufacturing a semiconductor light emitting device disclosed in Japanese Patent Laid-Open No. 11-163403;

6 is a view showing an example of a group III nitride semiconductor light emitting device according to the present disclosure;

7 is a view showing an example of a substrate provided in a group III nitride semiconductor light emitting device according to the present disclosure;

8 is a view showing another example of a substrate provided in the group III nitride semiconductor light emitting device according to the present disclosure;

9 is a view showing another example of a substrate provided in the group III nitride semiconductor light emitting device according to the present disclosure;

10 is a view showing an example of a method of manufacturing a group III nitride semiconductor light emitting device according to the present disclosure;

11 is a micrograph viewed from above of a substrate processed according to this Experimental Example;

12 is a photomicrograph of the substrate from above, in which scattering regions are formed at intervals according to the present experimental example;

FIG. 13 is a photograph seen from above of a group III nitride semiconductor light-emitting device comprising a substrate processed according to this Experimental Example. FIG.

Claims (8)

A substrate having a scattering region formed therein; The scattering region may include: a substrate formed such that a substrate is transformed inside the substrate by a laser to have various scattering angles; And, A first group III nitride semiconductor layer formed on the substrate and having a first conductivity, a second group III nitride semiconductor layer formed on the first group III nitride semiconductor layer and having a second conductivity different from the first conductivity, and the first third A group III nitride semiconductor layer comprising a plurality of group III nitride semiconductor layers positioned between the group nitride semiconductor layer and the second group III nitride semiconductor layer and having an active layer that generates light by recombination of electrons and holes; Light emitting element. delete In claim 1, A scattering region is a group III nitride semiconductor light emitting device, characterized in that formed continuously across the substrate. In claim 1, A group III nitride semiconductor light emitting device, characterized in that a plurality of scattering regions are formed on the substrate. In claim 1, A group III nitride semiconductor light emitting device, characterized in that the substrate is made of sapphire. In claim 1, A scattering region is a group III nitride semiconductor light emitting device, characterized in that formed on the inside of the substrate. delete delete

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