KR101619110B1 - Semi-conductor optoelectronic dcvice and method for manufacturing the same - Google Patents

Abstract

The present invention relates to a method of manufacturing a semiconductor optoelectronic device comprising a nitride of a Group III element.
The present invention provides a method of manufacturing a semiconductor device, comprising: forming a plurality of dots for p-type semiconductor which are scattered so as to be in contact with a p-type semiconductor; (B) forming a transparent electrode for a p-type semiconductor of graphene to cover the plurality of p-type semiconductor dots and the p-type semiconductor; And (C) forming a P-type electrode on the transparent electrode for the P-type semiconductor,
The step (A) may include depositing a powder of a transparent metal oxide selected from indium tin oxide, gallium-doped zinc oxide, zinc oxide, and indium gallium oxide on the P-type semiconductor; Partially crystallizing the powder of the transparent metal oxide through heat treatment; And etching the powder of the uncrystallized transparent metal oxide, wherein the step (B) comprises: mixing a graphene oxide solution with hydrazine as a diluent to form a mixed solution; And applying the mixed solution to the P-type semiconductor layer which has been heated in advance.

Description

TECHNICAL FIELD [0001] The present invention relates to a semiconductor optoelectronic device, and a manufacturing method thereof. BACKGROUND ART < RTI ID = 0.0 >

The present invention relates to a semiconductor optoelectronic device, and more particularly to a nitride semiconductor optoelectronic device including a nitride of a Group 3 element (gallium (Ga), aluminum (Al), indium (In), or the like). The present invention also relates to a method of manufacturing the semiconductor optoelectronic device.

Group III nitride, which is a mixture of Group 3 elements such as gallium (Ga), aluminum (Al) and indium (In) and nitrogen (N), has excellent thermal stability and has a direct transition type energy band structure. Recently, Group III nitride has been widely used for the fabrication and application of optoelectronic devices such as light emitters, photodetectors, photovoltaic cells, etc. covering the infrared (IR), visible and ultraviolet (UV) .

The nitride semiconductor opto-electronic device 10 having a group III nitride generally comprises a sapphire substrate 20 as shown in FIG. 1, an N-type semiconductor layer 30 sequentially stacked on the substrate 20, an active layer 40, and a P-type semiconductor layer 50. A part of the active layer 40 and the P-type semiconductor layer 50 which are photographed on the N-type semiconductor layer 30 are removed by etching so that a part of the upper surface of the N-type semiconductor layer 30 is exposed. The P-type semiconductor layer 30 is provided with a P-type electrode 72 and the exposed upper surface of the N-type semiconductor layer 30 is provided with an N-type electrode 74. The active layer 40 is a region where electrons and holes are recombined. When the photoelectric device 10 is a light emitting device, light having a predetermined wavelength is emitted, and the photoelectric device 10 generates a light receiving element or a photovoltaic In the case of an element, it absorbs light having a predetermined wavelength. The wavelength of light emitted or absorbed by the active layer 40 varies depending on the type of material forming the active layer 40.

On the other hand, when the N-type semiconductor layer 30 is formed on the substrate 20, the N-type semiconductor layer 30 is cracked due to the difference in lattice constant and thermal expansion coefficient between the N-type semiconductor layer 30 and the substrate 20 , Distortion and dislocation occur. The cracks, warpage, and electric potential deteriorate the characteristics of the photoelectric element 10. Therefore, a buffer layer (not shown) may be provided between the substrate 20 and the N-type semiconductor layer 30.

When the P-type electrode 72 is directly provided on the P-type semiconductor layer 50, a current flow is concentrated on a lower portion of the P-type electrode 72. [ For example, if the photoelectric element 10 is a light emitting element and a forward voltage is applied to the light emitting element, an operating current flowing from the P-type electrode 72 to the P-type semiconductor layer 50 flows to the entire surface of the P- And is concentrated at the lower portion of the P-type electrode 72 without being spread evenly. Due to such a phenomenon, the operating current is not uniformly spread over the entire surface of the active layer 40, thereby reducing the efficiency of the light emitting device.

A technique has been known in which a transparent electrode 60 is provided on the entire upper surface of a P-type semiconductor layer 50 and a P-type electrode 72 is provided on an upper surface of the transparent electrode 60 in order to solve the above problem . As the transparent electrode 60, a metal thin film of Ni or Au having a thickness of several nanometers or a transparent conductive oxide film such as ITO (Indium Tin Oxide) or GZO (Ga-doped ZnO) , Transparent Conducting Oxide) is used.

In order for the transparent electrode 60 to function, it must have low sheet resistance and high light transmittance. However, in the case of the metal thin film, if the thickness is large, the sheet resistance is lowered while the light transmittance is decreased. If the thickness is thin, the light transmittance is improved, but the sheet resistance is increased.

In addition, in the case of the above-mentioned transparent conductive oxide film, there is a problem that light transmittance sharply decreases in the ultraviolet ray region and a high sheet resistance is higher than that of metal.

SUMMARY OF THE INVENTION The present invention has been made to solve the conventional problems as described above and it is an object of the present invention to provide a graphene which has not only superior conductivity than metal but also excellent light transmittance over the infrared (IR), visible light and ultraviolet (UV) Which is used as a transparent electrode material. It is another object of the present invention to provide a method of manufacturing the semiconductor optoelectronic device.

According to an aspect of the present invention, there is provided a light emitting device including: a light source including an N-type semiconductor layer, an active layer, and a P-type semiconductor layer sequentially laminated; A plurality of p-type semiconductor dots scattered to be in contact with the p-type semiconductor; A transparent electrode made of a graphene material and provided so as to cover the plurality of p-type semiconductor dots and the p-type semiconductor; And a P-type electrode arranged to be in contact with the transparent electrode for the P-type semiconductor.

The p-type semiconductor dot is made of a transparent metal oxide or an alloy, and the transparent metal oxide is selected from indium tin oxide, gallium-doped zinc oxide, zinc oxide and indium gallium oxide.

The semiconductor opto-electronic device comprising: a plurality of n-type semiconductor dots scattered so as to be in contact with the n-type semiconductor; An N-type semiconductor transparent electrode made of a graphene material and covering the plurality of N-type semiconductor dots and the N-type semiconductor; And an N-type electrode configured to be in contact with the transparent electrode for the N-type semiconductor.

A method of manufacturing a semiconductor optoelectronic device including an N-type semiconductor layer, an active layer and a P-type semiconductor layer sequentially laminated, comprising the steps of: (A) providing a plurality of p- ; (B) forming a transparent electrode for a p-type semiconductor of graphene to cover the plurality of p-type semiconductor dots and the p-type semiconductor; And (C) forming a P-type electrode on the transparent electrode for the P-type semiconductor.

The step (A) includes the steps of: (A-1) depositing a transparent metal oxide powder on the P-type semiconductor; (A-2) partially crystallizing the transparent metal oxide powder through heat treatment; And (A-3) etching the uncrystallized transparent metal oxide powder. The transparent metal oxide is selected from indium tin oxide, gallium-doped zinc oxide, zinc oxide, and indium gallium oxide.

The step (B) may include the steps of: (B-1) mixing a graphene oxide solution with hydrazine as a diluent to form a mixed solution; And (B-2) applying the mixed solution onto the P-type semiconductor layer heated in advance.

A method of manufacturing a semiconductor optoelectronic device, comprising the steps of: (D) forming a plurality of dots for an N-type semiconductor to be scattered so as to be in contact with the N-type semiconductor; (E) forming a transparent electrode for n-type semiconductor of graphene to cover the plurality of n-type semiconductor dots and the n-type semiconductor; And (F) forming an N-type electrode on the transparent electrode for the N-type semiconductor.

According to the present invention, graphene, which is the thinnest among the materials known so far, can best conduct electricity and has excellent light transmittance over the infrared (IR), visible light and ultraviolet (UV) . Therefore, the present invention can emit or absorb light in a wide wavelength band as compared with the conventional art, and has superior performance to the conventional art.

Further, according to the present invention, since a plurality of dots are scattered on the surface of the whole light, good ohmic contact is established between the transparent electrode of the graphene and the semiconductor layer of the group III nitride. Therefore, the present invention does not cause the change or deterioration of the characteristics of the whole light even though the transparent electrode is provided as a graphene material.

1 is a cross-sectional view showing a conventional semiconductor photoelectric device.
2 is a cross-sectional view showing a semiconductor photoelectric device according to the present invention.
3 is a cross-sectional view showing a modification of the semiconductor optoelectronic device shown in FIG.
4 is a cross-sectional view showing still another modification of the semiconductor opto-electronic device shown in Fig.
FIG. 5 is a photograph of the semiconductor optoelectronic device shown in FIG. 2 in which dots are formed and a state in which transparent electrodes are formed by an electron microscope.
6 is a graph showing a result of performance test of the semiconductor optoelectronic device shown in FIG.

Hereinafter, preferred embodiments of a semiconductor optoelectronic device and a manufacturing method thereof according to the present invention will be described in detail with reference to the drawings. It is to be understood that the terminology or words used herein are not to be construed in an ordinary sense or a dictionary, and that the inventor can properly define the concept of a term to describe its invention in the best possible way And should be construed in accordance with the meaning and concept consistent with the technical idea of the present invention.

2, the semiconductor opto-electronic device 100 according to the present invention includes a plurality of p-type semiconductor dots 162a, a p-type semiconductor transparent electrode 164a, a p- Electrode 172 as shown in FIG.

The whole light is used for converting electric energy into light energy (when the photoelectric device 100 is a light emitting device) or converting light energy into electric energy (when the photoelectric device 100 is a light receiving device or a photovoltaic power generating device) And includes an N-type semiconductor layer 130, an active layer 140, and a P-type semiconductor layer 150 which are sequentially formed on a substrate 120. A part of the active layer 140 and the P-type semiconductor layer 150 that are photographed on the N-type semiconductor layer 130 are removed by etching, Structure.

The P-type semiconductor layer 130 and the N-type semiconductor layer 150 are made of a group III nitride which is a mixture of a group III element such as gallium (Ga), aluminum (Al) and indium (In) and nitrogen (N). The active layer 140 has a quantum well layer (not shown) and a quantum barrier layer (not shown) as regions where electrons and holes are recombined. When the photoelectric device 100 is a light emitting device, the active layer 140 emits light having a predetermined wavelength, and when the photoelectric device 100 is a light receiving device or a photovoltaic power generating device, Absorbed. The wavelength of the light emitted or absorbed by the active layer 140 depends on the type of the material forming the active layer 140.

The substrate 120 is made of a material suitable for growing Group III nitride single crystals such as sapphire, zinc oxide (ZnO), gallium nitride (GaN), aluminum nitride (AlN), or the like.

When the N-type semiconductor layer 130 is formed directly on the substrate 120, a difference in lattice constant and thermal expansion coefficient between the N-type semiconductor layer 130 and the substrate 120 causes a crack , Distortion and dislocation occur. The cracks, warps, and potentials deteriorate the characteristics of the photoelectric element 100. Therefore, a buffer layer (not shown) may be provided between the substrate 120 and the N-type semiconductor layer 130. The buffer layer is made of a group III nitride (GaN, AlN, AlGaN, InGaN, AlGaInN or the like).

The p-type semiconductor transparent electrode 164a is provided to cover a plurality of p-type semiconductor dots 162a and the p-type semiconductor layer 150, and is made of graphene. Graphene is a material having a hexagonal planar arrangement of carbon monolayers, which, despite being very thin, not only possesses better conductivity than metals but also has excellent light transmittance over the infrared (IR), visible and ultraviolet (UV) regions. Therefore, in order to overcome the disadvantages of metal or transparent conductive oxide (TCO) used as a material of the transparent electrode, graphene is used as the material of the transparent electrode 164a for the p-type semiconductor.

In order for the P-type semiconductor transparent electrode 164a to have no influence on the characteristics of the whole light when the P-type semiconductor transparent electrode 164a and the P-type semiconductor layer 150 are in contact with each other, A good ohmic contact should be made between the p-type semiconductor layer 164a and the p-type semiconductor layer 150. [ However, if the p-type semiconductor transparent electrode 164a is made of graphene and the p-type semiconductor layer 150 is made of a group III nitride, the transparent electrode 164a for p-type semiconductor and the p- Ohm contact is not achieved. Thus, the semiconductor opto-electronic device 100 includes a plurality of p-type semiconductor dots 162a.

The plurality of p-type semiconductor dots 162a have a nano size and are scattered on the p-type semiconductor 150 to be in contact with the p-type semiconductor 150 and are covered with the transparent electrode 164a for p-type semiconductor. The plurality of p-type semiconductor dots 162a are made of a material such as a transparent metal oxide, an alloy, or the like. As the transparent metal oxide, indium tin oxide (ITO), gallium doped zinc oxide (GaZnO), zinc oxide (ZnO), and indium gallium zinc oxide (InGaZnO) are used.

The P-type electrode 172 is provided to be in electrical contact with the P-type semiconductor transparent electrode 164a. On the exposed surface of the N-type semiconductor layer 130, an N-type electrode 74 is provided as shown in FIG.

Hereinafter, the operation of the semiconductor opto-electronic device 100 will be described as an example in which the semiconductor opto-electronic device 100 is a light-emitting device.

When the semiconductor opto-electronic device 100 is a light emitting device and a forward operation voltage is applied between the p-type electrode 172 and the n-type electrode 174, the operating current flows through the transparent electrode 164a for the p-type semiconductor and the plurality of dots 162a Type electrode 174 while passing through the P-type semiconductor layer 150, the active layer 140 and the N-type semiconductor layer 130 in this order. In this process, light is generated in the active layer 140. After passing through the P-type semiconductor layer 150, the light passes through the transparent electrode 164a for p-type semiconductor and the plurality of dots 162a and is emitted to the outside .

Hereinafter, a method of manufacturing the semiconductor opto-electronic device 100 including the p-type semiconductor dot 162a made of a transparent metal oxide will be described with reference to an example in which the transparent metal oxide is indium tin oxide (ITO).

The semiconductor opto-electronic device 100 includes a dot forming step and a transparent electrode forming step. The dot forming step is a step of forming a plurality of dots 162a on the P-type semiconductor layer 150 of the whole light. In the transparent electrode forming step, the transparent electrodes 164a for P-type semiconductor are formed on the plurality of dots 162a ).

The dot forming step includes three steps. In the first step, an indium tin oxide (ITO) powder is deposited on the P-type semiconductor 150 by an electron beam deposition method. FIG. 5 (a) shows a photograph observed by an electron microscope after the first step is performed. In the second step, the deposited ITO powder is partially crystallized through heat treatment. The heat treatment is performed at a temperature of 400 DEG C or higher. FIG. 5 (b) shows a photograph observed by an electron microscope after the second step is performed. In the third step, uncrystallized ITO powder is etched. At this time, a hydrochloric acid dilution liquid is used for the etching. When the third step is performed, the amorphous portion is removed as shown in FIG. 5 (c), and only the crystallized portion is left as a plurality of dots 162a.

In the transparent electrode formation step, a transparent electrode 164a for a p-type semiconductor of a graphene material is formed through a chemical synthesis method or a CVD growth method. FIG. 5 (d) shows a photograph observed with an electron microscope after the transparent electrode forming step is performed.

In the chemical synthesis method, a dilute solution such as a graphene oxide solution and a liquid hydrazine is first mixed. In this case, the oxidized graphene, which has lost its graphene property, is reduced again to become a material having a characteristic similar to graphene (CCG, cham- able converted graphene). Then, the mixed solution is applied on the P-type semiconductor layer 150 which has been heated in advance. The application is performed by supplying the mixed solution onto the heated P-type semiconductor layer 150 with a syringe, or spraying the mixed solution onto the heated P-type semiconductor layer 150. A transparent electrode 164a for a P-type semiconductor is formed after a predetermined time has passed after the mixed liquid is applied.

In the CVD (CVD) growth method, first, a transition metal (Ni, Cu, Pt) which absorbs carbon well is prepared as a catalyst layer, and then an appropriate amount of a mixed gas (hydrogen, argon, etc.) is injected at a high temperature of 1000 degrees or more. When carbon is reacted with the catalyst layer by the mixed gas and quenched, carbon is separated from the catalyst and graphene is grown on the surface. Then, when the catalyst layer is removed through etching, a graphene film is formed. When the graphene film is placed on the p-type semiconductor dot 162a and then heat treatment is performed, a transparent electrode 164a for a p-type semiconductor is formed.

Thereafter, the P-type electrode 172 is formed on the P-type semiconductor transparent electrode 164a and the N-type electrode 174 is formed on the exposed surface of the N-type semiconductor 130, Is completed.

A predetermined experiment has been performed to confirm the performance of the semiconductor opto-electronic device 100. In this experiment, the photoelectric device 100 was composed of a light emitting device, and the entire light was configured to generate ultraviolet rays having a wavelength of 380 nm. Also, in the above experiment, when the ITO thin film is used as the transparent electrode 164a for the p-type semiconductor and the p-type semiconductor dot 162a is not provided, the graphene film formed by the CVD growth method is used as the transparent electrode for the p- Type semiconductor dot 162a is not provided, the transparent electrode 164a for the p-type semiconductor is formed by using the graphene film formed by the CVD growth method and the p-type semiconductor dot 162a is formed And a transparent electrode 164a for a p-type semiconductor made of a graphene is formed by a chemical synthesis method and a dot 162a for a p-type semiconductor is provided. When the P-type semiconductor dot 162a is provided, ITO is used as the material.

The results of the above experiment are shown in Fig. 6 (a) shows the relationship between the operating voltage and the operating current of the light emitting device, and Fig. 6 (b) shows the light output according to the operating current.

6A, when the p-type semiconductor dot 162a is provided, irrespective of the method of forming the transparent electrode 164a for the p-type semiconductor of the graphene, the p-type semiconductor transparent electrode 164a and the p- When the p-type semiconductor dot 162a is not provided, the transparent electrode 164a for the p-type semiconductor and the p-type semiconductor layer 150 for the p-type semiconductor are formed in a good ohmic contact between the p- It can be seen that no good ohmic contact is made between the electrodes.

6 (b), the light output of the light emitting element is used as the transparent electrode 164a for the p-type semiconductor, compared with the case where the ITO is used as the transparent electrode 164a for the p-type semiconductor It can be seen that it is excellent when the P-type semiconductor dot 162a is provided.

As described above, the N-type electrode 174 is provided directly on the exposed surface of the N-type semiconductor layer 130. However, as shown in FIG. 3, the N-type semiconductor dot 162b and the N-type semiconductor transparent electrode 164b may be provided between the N-type electrode 174 and the exposed surface of the N-type semiconductor layer 130 . The structure, material, and formation method of the dot 162b and the transparent electrode 164b are the same as those of the p-type semiconductor dot 162a and the transparent electrode 164a.

According to the semiconductor opto-electronic device 100 described above, the N-type semiconductor layer 130 is partially exposed by etching the P-type semiconductor layer 150 and the active layer 140. However, as shown in FIG. 4, the semiconductor opto-electronic device 100 may be provided without partial exposure of the N-type semiconductor layer 130.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It is to be understood that the invention may be variously varied and modified within the scope of the appended claims.

100: semiconductor optoelectronic device 120: substrate
130: N-type semiconductor layer 140: active layer
150: P-type semiconductor layer 162a: P-type semiconductor dot
162b: N-type semiconductor dot 164a: P-type semiconductor transparent electrode
164b: N-type semiconductor transparent electrode 172: P-type electrode
174: N-type electrode

Claims (4)

delete delete A method of manufacturing a semiconductor optoelectronic device including an N-type semiconductor layer, an active layer and a P-type semiconductor layer sequentially laminated,
(A) forming a plurality of dots for p-type semiconductor which are scattered so as to be in contact with the p-type semiconductor;
(B) forming a transparent electrode for a p-type semiconductor of graphene to cover the plurality of p-type semiconductor dots and the p-type semiconductor; And
(C) forming a P-type electrode on the transparent electrode for the P-type semiconductor,
The step (A) may include depositing a powder of a transparent metal oxide selected from indium tin oxide, gallium-doped zinc oxide, zinc oxide, and indium gallium oxide on the P-type semiconductor; Partially crystallizing the powder of the transparent metal oxide through heat treatment; And etching the powder of the uncrystallized transparent metal oxide,
In the step (B), mixing a graphene oxide solution with hydrazine as a diluent to form a mixed solution; And applying the mixed solution to the P-type semiconductor layer which has been heated in advance. The method of claim 3,
(D) forming a plurality of n-type semiconductor dots scattered so as to be in contact with the n-type semiconductor;
(E) forming a transparent electrode for n-type semiconductor of graphene to cover the plurality of n-type semiconductor dots and the n-type semiconductor; And
(F) forming an N-type electrode on the transparent electrode for the N-type semiconductor.

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