KR100513349B1 - Nitride based semiconductor light emitting device and fabricating method thereof - Google Patents

Abstract

The present invention relates to a nitride semiconductor light emitting device and a method of manufacturing the same. The present invention provides a substrate for growing a nitride semiconductor material; An n-type nitride semiconductor layer formed on the substrate; An active layer formed on the n-type nitride semiconductor layer to expose at least a portion of the region on the n-type nitride semiconductor layer; A p-type nitride semiconductor layer formed on the active layer; A transparent electrode layer formed on the p-type nitride semiconductor layer to make ohmic contact; A p-side bonding electrode comprising a first Cr layer formed on the transparent electrode layer and a first Au layer formed on the first Cr layer; And a second Cr layer formed on the exposed portion of the n-type nitride semiconductor layer and having the same thickness as the first Cr layer, and formed on the second Cr layer and having the same thickness as the first Au layer. A nitride semiconductor light emitting device comprising an n-side electrode made of a second Au layer is provided.

Description

Nitride semiconductor light emitting device and its manufacturing method {NITRIDE BASED SEMICONDUCTOR LIGHT EMITTING DEVICE AND FABRICATING METHOD THEREOF}

The present invention relates to a nitride semiconductor light emitting device, and more particularly, by forming the p-side bonding electrode and the n-side electrode of the nitride semiconductor light emitting device in a double layer of Cr / Au, ohmic contact can be formed at room temperature without a separate heat treatment process. The present invention relates to a nitride semiconductor light emitting device capable of excellent appearance and excellent wire bonding characteristics, and a method of manufacturing the same.

In recent years, nitride semiconductors using nitrides such as GaN have been spotlighted as core materials for photoelectric materials and electronic devices due to their excellent physical and chemical properties. In particular, the nitride semiconductor light emitting device can generate light up to the green, blue, and ultraviolet regions, and has been applied to the fields of full color display boards, lighting devices, etc., as the brightness is dramatically improved due to the development of technology.

Such a nitride semiconductor light emitting device is a light emitting device for obtaining light in a blue or green wavelength band, and has a composition formula of Al _x In _y Ga _(1-xy) N (where 0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ x + y ≦ 1). The nitride semiconductor crystal is grown on a nitride single crystal growth substrate such as a sapphire substrate in consideration of lattice matching. Since the sapphire substrate is an electrically insulating substrate, the final nitride semiconductor light emitting device has a structure in which the p-side electrode and the n-side electrode are formed on the same surface.

In general, a nitride semiconductor light emitting device includes an n-type nitride semiconductor layer sequentially formed on a substrate, an active layer having a multi-well structure, and a p-type nitride semiconductor layer, and the p-type nitride semiconductor layer and the active layer are partially removed. The upper surface of a portion of the n-type nitride semiconductor layer is exposed. An n-side electrode (also referred to as N-metal) is formed on the exposed n-type nitride semiconductor layer, and a transparent electrode layer (T-metal) is formed on the p-type nitride semiconductor layer to form ohmic contact and improve current injection efficiency. After forming a P-side bonding electrode (also referred to as B-metal) on the upper surface of the transparent electrode layer.

One of the important processes for fabricating a nitride semiconductor light emitting device is a process of forming an electrode capable of passing a current through a diode. In the general nitride semiconductor light emitting device having the above-described structure, a component referred to as an 'electrode' includes an n-side electrode, a transparent electrode layer, and a p-side bonding electrode. The n-side electrode should have ohmic characteristics in contact with the n-nitride semiconductor layer, and the transparent electrode layer should have ohmic characteristics in contact with the p-nitride semiconductor layer and at the same time have a high transmittance to transmit light. In addition, the p-side bonding electrode is used as a wire bonding electrode for electrical connection with an external circuit, and the wire bonding property must be good so that wire bonding can be made firmly. Similarly, since the n-side electrode is also used for wire bonding for electrical connection with an external circuit, the n-side electrode should have excellent ohmic properties and excellent bonding properties with the n-nitride semiconductor layer.

Conventionally, the transparent electrode layer bonded to the p-type nitride semiconductor layer to form a low driving voltage and low contact resistance (ohmic contact) characteristics of the nitride semiconductor light emitting device forms a double layer of Ni / Au or an ITO layer. After the heat treatment, the p-side bonding electrode for wire bonding was formed as a double layer of Cr / Au on the upper surface of the transparent electrode layer. In addition, the n-side electrode was used by forming a double layer of Ti / Al on the exposed upper surface of the n-type nitride semiconductor layer.

In such a conventional nitride semiconductor light emitting device, the n-side electrode having a dual layer structure of Ti / Al is heat-treated at a temperature of 400 ° C. or higher to obtain excellent ohmic characteristics because the ohmic characteristics are inferior at room temperature (the contact resistance is large). The process must be involved. Therefore, the conventional nitride semiconductor light emitting device may have a complicated production process and a problem in that the manufacturing cost increases.

In addition, when Ti / Al is used as the p-side bonding electrode in the conventional nitride semiconductor light emitting device, the p-side bonding electrode cannot use Ti / Al because the ohmic characteristic is very deteriorated. Therefore, since the p-side bonding electrode and the n-side electrode should be made of Cr / Au and Ti / Al, respectively, the p-side bonding electrode and the n-side electrode cannot be simultaneously formed on the nitride semiconductor layer. As such, in the related art, a material for forming the p-side bonding electrode and the n-side electrode must be separately provided, and must be formed through a separate process, which also complicates the production process, resulting in an increase in manufacturing cost. Can be.

In particular, Al, which is conventionally used as one of the materials for forming the n-side electrode, is easily damaged by an alkaline solution or the like, and is easily damaged during subsequent processing, resulting in a poor appearance of the nitride semiconductor light emitting device. 3A and 3B are photographs showing appearance defects occurring in an n-side electrode using Al in the related art. As shown in FIG. 3A, the conventional n-side electrode has a poor appearance in which stains occur due to contamination, oxidation, and corrosion of Al.

In addition, since wire bonding characteristics are degraded due to contamination, oxidation, and corrosion of Al, the conventional n-side electrode has a potential problem of always causing wire bonding defects.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to form a p-side bonding electrode and an n-side electrode, which are electrodes of a nitride semiconductor light emitting device, by forming a double layer of Cr / Au, and simultaneously p-side bonding electrode and n-side electrode. The present invention provides a nitride semiconductor light emitting device capable of forming an electrode, forming an ohmic contact even at room temperature without a separate heat treatment process, improving appearance defects, and having excellent wire bonding characteristics, and a method of manufacturing the same.

The present invention to achieve the above technical problem,

A substrate for growing a nitride semiconductor material;

An n-type nitride semiconductor layer formed on the substrate;

An active layer formed on the n-type nitride semiconductor layer to expose at least a portion of the region on the n-type nitride semiconductor layer;

A p-type nitride semiconductor layer formed on the active layer;

A transparent electrode layer formed on the p-type nitride semiconductor layer to make ohmic contact;

A p-side bonding electrode comprising a first Cr layer formed on the transparent electrode layer and a first Au layer formed on the first Cr layer; And

A second Cr layer formed on the exposed portion of the n-type nitride semiconductor layer and having the same thickness as the first Cr layer, and formed on the second Cr layer and having the same thickness as the first Au layer. A nitride semiconductor light emitting device including an n-side electrode including a second Au layer is provided.

In the nitride semiconductor light emitting device according to the present invention, the first Cr layer and the second Cr layer have a thickness of 50 kPa to 1000 kPa, and the first Au layer and the second Au layer have a thickness of 2000 kPa to 7000 kPa. It is preferable.

The present invention also provides a method of manufacturing the nitride semiconductor device. The method,

Providing a substrate for growing a nitride semiconductor material;

Sequentially forming an n-type nitride semiconductor layer, an active layer, and a p-type nitride semiconductor layer on the substrate;

Removing a portion of the at least p-type nitride semiconductor layer and the active layer to expose a portion of the n-type nitride semiconductor layer;

Forming a transparent electrode layer on the p-type nitride semiconductor layer; And

Simultaneously forming a first Cr layer and a second Cr layer on the transparent electrode layer and the exposed n-type nitride semiconductor layer at the same thickness; And simultaneously forming a first Au layer and a second Au layer on the first Cr layer and the second Cr layer, respectively, at the same thickness.

Preferably, the forming of the first Cr layer and the second Cr layer is selected from the group consisting of chemical vapor deposition, electron beam evaporation, and sputtering on exposed portions of the transparent electrode layer and the n-type nitride semiconductor layer. And forming each of the first Cr layer and the second Cr layer by using a method of 50 kPa to 1000 kPa on exposed portions of the transparent electrode layer and the n-type nitride semiconductor layer. Each step is formed in thickness.

Preferably, the forming of the first Au layer and the second Au layer may be performed using a method selected from the group consisting of chemical vapor deposition, electron beam evaporation, and sputtering on the first Cr layer and the second Cr layer, respectively. Forming.

Preferably, the forming of the first Au layer and the second Au layer is a step of forming a thickness of 2000 kPa to 7000 kPa on the first Cr layer and the second Cr layer, respectively.

In addition, the method of manufacturing the nitride semiconductor light emitting device according to the present invention may further include heat-treating the first and second Cr layers and the first and second Au layers at 400 ° C to 600 ° C.

Hereinafter, a nitride semiconductor light emitting device and a method of manufacturing the same according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view of a nitride semiconductor light emitting device according to one embodiment of the present invention. As shown in FIG. 1, a nitride semiconductor light emitting device according to an exemplary embodiment of the present invention includes a substrate 11 for growing a nitride semiconductor material, formed on the substrate 11, and formed with the substrate 11. A buffer layer 11a for relaxing lattice mismatch with the upper n-type nitride semiconductor layer 12, an n-type nitride semiconductor layer 12 formed on the buffer layer 11a, and the n-type nitride semiconductor layer ( 12) an active layer 13 formed on the n-type nitride semiconductor layer so that at least a portion of the region is exposed, the p-type nitride semiconductor layer 14 formed on the active layer, and the p-type nitride semiconductor layer A double layer of Cr / Au on the exposed portion of the transparent electrode layer 15 and a p-side bonding electrode 17 formed of a double layer of Cr / Au on the transparent electrode layer 15 and the n-type nitride semiconductor layer. N-side electrode 16 is formed.

The substrate 11 is a sapphire substrate or a SiC substrate in consideration of lattice matching because no commercial substrate having the same crystal structure and lattice matching as the crystal structure of the nitride semiconductor material grown thereon exists. In particular, the sapphire substrate is a Hexa-Rhombo R3c symmetric crystal and has a lattice constant of 13.001Å in the c-axis direction and 4.765Å in the a-axis direction, and has a sapphire orientation plane. ) Is characterized by having a C (0001) plane, an A (11 2 0) plane, an R (1 1 02) plane, and the like. In the case of the C surface of the sapphire substrate, the GaN thin film is relatively easy to grow, and is cheaper than the SiC substrate and stable at high temperature, and thus, sapphire substrate is mainly used as a substrate for a blue or green light emitting device.

The buffer layer 11a is formed to mitigate lattice mismatch between the substrate 11 and the n-type nitride semiconductor layer formed on the substrate 11, and is usually made of GaN or AlN having a thickness of several tens of nm. Low temperature nucleus growth layer is used. In the present embodiment, the buffer layer 11a is included in the structure of the nitride light emitting device, but this is merely an example for explaining the structure of a general nitride light emitting device and is not intended to limit the present invention.

The n-type nitride semiconductor layer 12 is n-doped with Al _x In _y Ga _(1-xy) N composition formula, where 0 ≦ x ≦ 1, 0 ≦ y ≦ 1, and 0 ≦ x + y ≦ 1. It can be made of a semiconductor material, a typical nitride semiconductor material is GaN, AlGaN, GaInN. As an impurity used for the doping of the n-type nitride semiconductor layer 12, Si, Ge, Se, Te, or C may be used. The n-type nitride semiconductor layer 12 may be formed of a metal organic chemical vapor deposition (MOCVD) method, a molecular beam growth method (MBE), or a hydride vapor deposition method (Hydride Vapor Phase Epitaxy). It is formed by growing on the buffer layer 11a using a known deposition process such as HVPE).

The active layer 13 is a layer for emitting light and is composed of a nitride semiconductor layer such as GaN or InGaN having a single or multiple quantum well structure. The active layer 13 is formed on the n-type nitride semiconductor layer 12 using a known deposition process such as organometallic vapor deposition, molecular beam growth, or hydride vapor deposition, like the n-type nitride semiconductor layer 12. It is formed on the n-type nitride semiconductor layer 12 to expose at least a portion of the region. A portion of the n-type nitride semiconductor layer 12 exposed is provided to form the n-side electrode 16 described later.

The p-type nitride semiconductor layer 14 is similar to the n-type nitride semiconductor layer 12, Al _x In _y Ga _(1-xy) N composition formula (where 0≤x≤1, 0≤y≤1, 0 ≦ x + y ≦ 1), and typical nitride semiconductor materials include GaN, AlGaN, and GaInN. Mg, Zn, or Be may be used as an impurity used for the doping of the p-type nitride semiconductor layer 14. The p-type nitride semiconductor layer 14 may be formed by using a known deposition process such as organometallic vapor deposition (MOCVD), molecular beam growth (MBE), or hydride vapor deposition (HVPE). 13) is formed by growing on.

Since the p-type nitride semiconductor layer 14 has a low impurity doping concentration and high contact resistance, ohmic characteristics are not good. Thus, in order to improve ohmic characteristics, a transparent electrode layer 15 (also called a T metal) is formed on the p-type nitride semiconductor layer 14. The transparent electrode layer 15 may be made of a metal having a relatively high transmittance, and a transparent electrode layer composed of a double layer of Ni / Au is widely used. The transparent electrode layer composed of the Ni / Au double layer is known to reduce the forward voltage V _f by forming an ohmic contact while increasing the current injection area. The transparent electrode layer 15 may be formed by a known deposition method such as chemical vapor deposition (CVD) and an electron beam evaporator (E-beam evaporator) or by a method such as sputtering.

The n-side electrode 16 (also referred to as N metal) is formed of a double layer composed of a Cr layer 16a and an Au layer 16b on an exposed portion of the n-type nitride semiconductor layer 12. The n-side electrode 16 should have good wire bonding characteristics to form wire bonding for current supply, and at the same time, it should be able to form ohmic contact with the n-type nitride semiconductor layer. The inventors of the present invention, through repeated experiments and studies in order to find the most suitable material that can satisfy the characteristics of the n-side electrode 16, it is most preferable to form the n-side electrode with a double layer of Cr / Au Got.

The n-side electrode 16 made of Cr / Au is formed on the exposed region of the n-type nitride semiconductor layer by a known deposition method such as chemical vapor deposition (CVD) and electron beam evaporation or sputtering. After forming the Cr layer 16a with a thickness, the Au layer 16b may be formed on the Cr layer 16a with a thickness of 2000 kPa to 7000 kPa.

The n-side electrode 16 made of Cr / Au has a feature of forming an ohmic contact even at room temperature. Conventional n-side electrode using Ti / Al does not form ohmic contact at room temperature, so the ohmic characteristics should be improved through a high temperature heat treatment process. However, since the n-side electrode 16 made of Cr / Au according to the present invention can form ohmic contact at room temperature, it does not need to undergo a separate heat treatment process. Therefore, the manufacturing process of the nitride semiconductor light emitting device can be simplified, and the manufacturing cost of the device can be reduced. In addition, since Al is not easily used, which is easily corroded to the alkaline solution and easily damaged during the process, the appearance defect of the nitride semiconductor light emitting device does not occur.

The p-side bonding electrode 17 (also referred to as B metal) is formed for wire bonding for current supply, and, like the n-side electrode 16, is composed of a Cr layer 17a and an Au layer 17b. The double layer is formed on the transparent electrode layer 15. The p-side bonding electrode 17 made of Cr / Au has a Cr layer 17a on the transparent electrode layer 15 with a thickness of 50 mV to 1000 mV by a known deposition method such as chemical vapor deposition, electron beam evaporation, or sputtering. After the formation, the Au layer 17b may be formed on the Cr layer 17a with a thickness of 2000 GPa to 7000 GPa. Since the p-side bonding electrode 17 made of Cr / Au is made of the same material as the n-side electrode 16, the p-side bonding electrode 17 may be formed simultaneously with the n-side electrode in the manufacturing process of the device. That is, Cr layers 16a and 17a are simultaneously formed on the exposed region of the n-type nitride semiconductor layer 12 and the transparent electrode layer 15, respectively, and then each Au layer (on the Cr layers 16a and 17a) is formed. 16b, 17b) can be formed simultaneously. Therefore, there is an advantage that the manufacturing process can be simplified as compared to the conventional manufacturing process of forming the n-side electrode 16 and the p-side bonding electrode 17 separately.

The n-side electrode 16 and the p-side bonding electrode 17 have good ohmic characteristics even without undergoing a heat treatment process. However, it may also have good ohmic characteristics through heat treatment of 400 ℃ to 600 ℃. Therefore, the n-side electrode 16 and the p-side bonding electrode 17 of the nitride semiconductor light emitting device according to the present invention may be heat treated at a temperature of 400 ° C to 600 ° C. In addition, Au has superior wire bonding characteristics than Al, and thus, the n-side electrode and the p-side bonding electrode used in the present invention have superior wire bonding characteristics than conventional electrodes. Therefore, according to the present invention, it is possible to solve the problem of potential wire bonding failure.

The present invention also provides a method of manufacturing a nitride semiconductor light emitting device configured as described above. A method of manufacturing a nitride semiconductor light emitting device according to an embodiment of the present invention will be described in detail with reference to FIG. 2.

2 is a process cross-sectional view showing a method for manufacturing a nitride semiconductor light emitting device according to one embodiment of the present invention.

First, as shown in FIG. 2A, a substrate 21 for growing a nitride semiconductor material is prepared, and then an n-type nitride semiconductor layer 22, an active layer 23, and a p-type nitride semiconductor layer 24 are formed on the sapphire substrate. ) Are formed sequentially. The n-type nitride semiconductor layer 22, the active layer 13 and the p-type nitride semiconductor layer 24 are well known, such as organometallic vapor deposition (MOCVD), molecular beam growth (MBE) or hydride vapor deposition (HVPE). Can be grown using a deposition process. Before forming the n-type nitride semiconductor layer 22 on the substrate 21, a buffer layer 21a may be formed on the upper surface of the substrate 21 to mitigate lattice mismatch.

2B, at least a portion of the p-type nitride semiconductor layer 24 and the active layer 23 are removed to expose a portion of the n-type nitride semiconductor layer 22. The exposed region of the n-type nitride semiconductor layer 22 is provided as a region where the n-side electrode is to be formed. The shape of the structure according to the present removal process may be changed in various forms according to the position to form the electrode, and the shape and size of the electrode may also be variously modified. For example, the present process may be implemented by removing an area in contact with one edge, and in order to disperse current density, the shape of the electrode may be formed to extend along the side.

Subsequently, as shown in FIG. 2C, the transparent electrode layer 25 is formed on the p-type nitride semiconductor layer 24. As described above, a transparent layer of Ni / Au may be mainly used as the transparent electrode layer 25, and by adopting a known deposition method or sputtering such as known chemical vapor deposition (CVD) and electron beam evaporation, Can be formed.

2D, Cr layers 26a and 27a are simultaneously formed on the exposed region of the n-type nitride semiconductor layer 22 and the transparent electrode layer 25, respectively. The Cr layer 26a formed on the n-type nitride semiconductor layer 22 constitutes an n-side electrode, and the Cr layer 27a formed on the transparent electrode layer 25 constitutes a p-side bonding electrode. Each of the Cr layers 26a and 27a is disposed on the exposed portions of the n-type nitride semiconductor layer 22 and the transparent electrode layer 25 by a method selected from the group consisting of chemical vapor deposition, electron beam evaporation, and sputtering. It is preferable that it is formed with a thickness of 50 kV to 1000 kPa.

Finally, as shown in FIG. 2E, the Au layers 26b and 27b are formed on the Cr layer 26a formed on the exposed region of the n-type nitride semiconductor layer 22 and the Cr layer 27a formed on the transparent electrode layer, respectively. ) At the same time. Like the Cr layers 26a and 27a, the Au layers 26b and 27b are preferably formed to have a thickness of 2000 kPa to 7000 kPa by a method selected from the group consisting of chemical vapor deposition, electron beam evaporation and sputtering.

As described above, in the present invention, since the n-side electrode and the p-side bonding electrode can be formed of the same material and the same structure, the process can be simplified compared to the conventional process of separately forming the p-side bonding pad and the n-side electrode. There is an advantage.

Additionally, the present invention may include a step of heat treating the n-side electrode and the p-side bonding electrode. The n-side electrode and p-side bonding electrode according to the present invention have good ohmic characteristics even without undergoing a heat treatment process. However, it may also have good ohmic characteristics through heat treatment of 400 ℃ to 600 ℃. Therefore, the method of manufacturing the nitride semiconductor light emitting device according to the present invention may further include a step of heat-treating the n-side electrode and the p-side bonding electrode at a temperature of 400 ° C to 600 ° C.

The inventors of the present invention fabricate a conventional nitride semiconductor light emitting device in which an n-side electrode is formed of a Ti / Al double layer, and a nitride semiconductor light emitting device according to the present invention in which an n-side electrode is formed of a Cr / Au double layer. Experiments were conducted to compare the appearance and to compare the ohmic characteristics and reliability. The results are shown in FIGS. 3 to 5.

3 is a photograph of appearance comparison of a conventional n-side electrode and an n-side electrode according to the present invention. In the conventional n-side electrode formed of a Ti / Al double layer, due to Al contamination, oxidation, and corrosion, defects appear in appearance as shown in FIG. 3A, and small dots are printed on the n-side electrode as shown in FIG. 3B. A spotty defect like this one appeared. On the other hand, the n-side electrode of the nitride semiconductor light emitting device according to the present invention had a feature of having an excellent appearance because the appearance defect by Al does not occur as shown in FIG. As described above, the nitride semiconductor light emitting device according to the present invention can solve the problem of appearance defects due to contamination, oxidation and corrosion of Al at the n-side electrode. In addition, potential wire bonding defects can be solved by preventing deterioration of wire bonding characteristics due to contamination, oxidation and corrosion of Al.

Figure 4a is a graph showing the results of experiments on the ohmic characteristics of the conventional n-side electrode composed of a double layer of Ti / Al, Figure 4b is a graph illustrating the ohmic characteristics of the n-side electrode composed of a double layer of Cr / Au according to the present invention It is a graph showing one result. As shown in Figure 4a, the n-side electrode made of conventional Ti / Al does not form ohmic contact at room temperature and 400 ℃. Conventional n-side electrodes exhibited ohmic characteristics only when heat treated at 500 ° C and 600 ° C. Therefore, the conventional Ti / Al electrode can form ohmic contact only when a heat treatment is performed at a high temperature of 500 ° C. or higher, and thus, a heat treatment process must be added.

On the other hand, as shown in Figure 4b, the n-side electrode composed of Cr / Au according to the present invention showed good ohmic characteristics in all cases subjected to heat treatment at room temperature and various temperatures. Therefore, in the nitride semiconductor light emitting device employing Cr / Au as the n-side electrode according to the present invention, ohmic contact can be formed even when the heat treatment process is not accompanied, and the heat treatment may be performed at 400 ° C. to 600 ° C.

5 is a reliability test result of a nitride semiconductor light emitting device having a conventional n-side electrode composed of Ti / Al and a nitride semiconductor light emitting device having an n-side electrode composed of Cr / Au according to the present invention. In this test, the conventional nitride semiconductor light emitting device and the nitride semiconductor light emitting device according to the present invention were operated for 500 hours under high temperature and high humidity conditions (high temperature and high humidity loads) and high temperature and low humidity conditions (high temperature loads), respectively. . As shown in FIG. 5A, the nitride semiconductor light emitting device including the n-side electrode composed of Ti / Al exhibits a luminance decrease of about 20% at both the high temperature and high humidity load and the high temperature load after 100 hours, and the high temperature and high humidity load after 500 hours. In the case of the high temperature load, the luminance decrease was more than 40%.

On the other hand, the nitride semiconductor light emitting device according to the present invention, as shown in Figure 5b, after 100 hours showed a luminance decrease of less than 20% for high temperature and high humidity load, less than 10% for high temperature load, after 500 hours high temperature and high humidity load In the case of, the decrease in luminance was measured to be less than 40% and less than 30% for the high temperature load.

Therefore, the nitride semiconductor light emitting device according to the present invention showed a significant improvement in terms of reliability, and in particular, at a high temperature load, the reliability improvement of more than 40% was achieved.

As described above, the present invention can simplify the process by using the n-side electrode and the p-side bonding electrode of the same Cr / Au double layer structure, it is possible to form the ohmic contact of the n-side electrode at room temperature, so that the heat treatment process Can be omitted. In addition, by not using the conventional Al as the constituent material of the electrode, it is possible to improve the appearance defects and to improve the wire bonding characteristics, it is possible to significantly improve the reliability compared to the conventional light emitting device.

The present invention is not limited by the above-described embodiment and the accompanying drawings, but is intended to be limited by the appended claims, and various forms of substitution, modification, and within the scope not departing from the technical spirit of the present invention described in the claims. It will be apparent to those skilled in the art that changes are possible.

As described above, according to the present invention, by forming the n-side electrode and the p-side bonding electrode of the nitride semiconductor light emitting device as a double layer of Cr / Au, two electrodes can be formed simultaneously and at room temperature without a separate heat treatment process. Since ohmic contacts can be formed, the manufacturing process of the nitride semiconductor light emitting device can be simplified. In addition, since Al is not used as the material of the electrode, poor appearance of the nitride semiconductor light emitting device can be improved, and at the same time, wire bonding characteristics can be improved. In addition, the reliability of the nitride semiconductor light emitting device can be significantly improved.

1 is a side cross-sectional view of a nitride semiconductor light emitting device according to one embodiment of the present invention.

2 is a process cross-sectional view showing a method of manufacturing a nitride semiconductor light emitting device according to one embodiment of the present invention.

3 is a photograph of appearance comparison of a conventional n-side electrode and an n-side electrode according to the present invention.

4 is a graph comparing ohmic characteristics of an n-side electrode composed of conventional Ti / Al and an n-side electrode composed of Cr / Au according to the present invention.

5 is a graph comparing reliability test results of a nitride semiconductor light emitting device according to the present invention and a conventional nitride semiconductor light emitting device.

* Description of the symbols for the main parts of the drawings *

11, 21: substrate 12, 22: n-type nitride semiconductor layer

13, 23: active layer 14, 24: p-type nitride semiconductor layer

15, 25: transparent electrode layer 16: n-side electrode

17: p-side electrode 16a, 26a, 27a: Cr layer

16b, 17b, 27b: Au layer

Claims (10)

A substrate for growing a nitride semiconductor material; An n-type nitride semiconductor layer formed on the substrate; An active layer formed on the n-type nitride semiconductor layer to expose at least a portion of the region on the n-type nitride semiconductor layer; A p-type nitride semiconductor layer formed on the active layer; A transparent electrode layer formed on the p-type nitride semiconductor layer to make ohmic contact; A p-side bonding electrode comprising a first Cr layer formed on the transparent electrode layer and a first Au layer formed on the first Cr layer; And A second Cr layer formed on the exposed portion of the n-type nitride semiconductor layer and having the same thickness as the first Cr layer, and formed on the second Cr layer and having the same thickness as the first Au layer. A nitride semiconductor light emitting device comprising an n-side electrode made of a second Au layer. The method of claim 1, And the first Cr layer and the second Cr layer have a thickness of 50 kPa to 1000 kPa, and the first Au layer and the second Au layer have a thickness of 2000 kPa to 7000 kPa. delete Providing a substrate for growing a nitride semiconductor material; Sequentially forming an n-type nitride semiconductor layer, an active layer, and a p-type nitride semiconductor layer on the substrate; Removing a portion of the at least p-type nitride semiconductor layer and the active layer to expose a portion of the n-type nitride semiconductor layer; Forming a transparent electrode layer on the p-type nitride semiconductor layer; And Simultaneously forming a first Cr layer and a second Cr layer on the transparent electrode layer and the exposed n-type nitride semiconductor layer at the same thickness; And And forming a first Au layer and a second Au layer on the first Cr layer and the second Cr layer, respectively, at the same thickness. delete The method of claim 4, wherein the forming of the first Cr layer and the second Cr layer comprises: Forming on the exposed portions of the transparent electrode layer and the n-type nitride semiconductor layer by using a method selected from the group consisting of chemical vapor deposition, electron beam evaporation, and sputtering, respectively. . The method of claim 4, wherein the forming of the first Cr layer and the second Cr layer comprises: And forming a thickness of 50 mW to 1000 mW on the exposed portions of the transparent electrode layer and the n-type nitride semiconductor layer, respectively. The method of claim 4, wherein the forming of the first Au layer and the second Au layer includes: Forming on the first Cr layer and the second Cr layer by using a method selected from the group consisting of chemical vapor deposition, electron beam evaporation, and sputtering, respectively. The method of claim 4, wherein the forming of the first Au layer and the second Au layer includes: Forming a nitride semiconductor light emitting device on the first Cr layer and the second Cr layer at a thickness of 2000 kPa to 7000 kPa. The method of claim 4, wherein And heat-treating the first and second Cr layers and the first and second Au layers at 400 ° C to 600 ° C.