KR100744941B1 - Electrode structure, semiconductor light-emitting device provided with the same and method for manufacturing the same - Google Patents

Abstract

Disclosed are an electrode structure of a semiconductor light emitting device, a semiconductor light emitting device employing the same, and a manufacturing method thereof. The disclosed semiconductor light emitting device includes a non-conductive substrate, a first lower clad layer formed on the non-conductive substrate, a conductive layer having a predetermined shape on the first lower clad layer, and a second lower clad layer formed on a predetermined region of the conductive layer. And an active region formed on the second lower clad layer, an upper clad layer formed on the active region, an upper electrode formed on the upper clad layer, and a lower electrode electrically connected to the conductive layer and formed on the remaining region of the conductive layer. do. Therefore, there is an effect that the operating voltage can be reduced by implementing a semiconductor light emitting device having a vertical structure that solves the current gathering phenomenon that has been a problem in the conventional semiconductor light emitting device.

Description

Electrode structure, semiconductor light emitting device having same and method for manufacturing the same {Electrode structure, semiconductor light-emitting device provided with the same and method for manufacturing the same}

1 is a schematic cross-sectional view for describing a semiconductor light emitting device manufactured according to the prior art.

2A to 2F are cross-sectional views illustrating a method for manufacturing a semiconductor light emitting device according to a preferred embodiment of the present invention.

3A is a plan view illustrating an electrode structure formed according to a preferred embodiment of the present invention.

3B is a plan view illustrating an electrode structure formed according to another exemplary embodiment of the present invention.

4 is a cross-sectional view for describing a semiconductor light emitting device according to an embodiment of the present invention.

5A to 5H are cross-sectional views illustrating a method for manufacturing a semiconductor light emitting device according to another exemplary embodiment of the present invention.

* Description of Signs of Major Parts of Drawings *

100, 200: semiconductor light emitting element 102, 202: transparent substrate                 

104, 204: first lower clad layer 106, 106A, 106B, 206: conductive layer

208: auxiliary layer 110 and 210: second lower clad layer

112, 212: active layer 114, 214: upper clad layer

116, 116A, 116B: n-type electrode 118, 218: p-type electrode

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a manufacturing method thereof, and more particularly, to an electrode structure of a semiconductor light emitting device, a semiconductor light emitting device employing the same, and a manufacturing method thereof.

In general, nitride-based compound semiconductors are widely used for visible light emitting devices, and are currently being developed as ultraviolet rays for white light emitting devices through blue and green visible light regions. In addition, the nitride compound semiconductor can be used as a light source for emitting light and a high density optical recording device capable of emitting light in the blue, green, and ultraviolet regions.

In addition, as the density of information recording increases, visible light laser oscillation is possible, and since the transition method is a direct transition type, group III-V nitride semiconductors having high luminous efficiency and blue laser oscillation, which is one of the three primary colors of light, are possible. Is especially noteworthy today.

1 is a schematic cross-sectional view for describing a nitride semiconductor light emitting device manufactured according to the prior art.

As shown in FIG. 1, the nitride semiconductor light emitting device 10 is sequentially formed on a transparent substrate 12 and a transparent substrate 12 made of a transparent material such as sapphire (Al ₂ O ₃ ) or silicon carbide (SiC). A lower cladding layer 14, an active region 16, an upper cladding layer 18, a current diffusion layer 20, and a p-type electrode 22 and a lower cladding layer 14 formed of n-AlGaN / GaN formed by being stacked. N-type electrode 24 formed in a predetermined region of the substrate.

The light efficiency of the nitride semiconductor light emitting device 10 having the above-described structure depends not only on recombination of electrons and holes in the active region 16 but also on the diffusion of current in the upper clad layer 18. That is, for efficient operation of the semiconductor light emitting device 10, the current injected by the p-type electrode 22 must be evenly distributed in the lateral direction, and the current evenly distributed in the lateral direction is obtained by AlGaInN of the double-hetero structure. Light is evenly generated by flowing across the pn junction.

However, it is difficult for the upper clad layer 18 made of p-type AlGaInN to be doped to have a high concentration of impurity. Moreover, while the mobility of holes is very low in the p-type AlGaInN semiconductor, the current injected from the p-type electrode 22 flows very fast in the current diffusion layer 20. Therefore, a problem arises in that a current diffuses only to a certain region due to a difference between a path of electrons flowing along the path B and an electron flowing along the path A.

In addition, due to the above-described problems, the electrical resistivity of the upper cladding layer 18 of the p-type AlGaInN is considerably higher, which results in a restriction in spreading current. A phenomenon occurs in which current is concentrated under the opposite side of the current spreading layer 20 electrically coupled with the electrode 22. This phenomenon is often referred to as current crowding phenomenon.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a technical problem to be achieved by the present invention is to provide an n-type electrode structure and a method for manufacturing the same, which can uniformly spread current in an active region.

Another object of the present invention is to provide a semiconductor light emitting device having an n-type electrode structure capable of uniformly spreading current in an active region, and a method of manufacturing the same.

According to one type of the present invention for achieving the above object, in a semiconductor light emitting device having a non-conductive substrate and a horizontal structure having an n-type semiconductor layer on the non-conductive substrate, a predetermined region of the n-type semiconductor layer An electrode structure is provided that includes an n-type electrode to be formed and a conductive layer formed in the n-type semiconductor layer and electrically connected to the n-type electrode to uniformly diffuse current in the n-type semiconductor layer.

According to another type of the invention, a non-conductive substrate, a first lower clad layer formed on the non-conductive substrate, a conductive layer having a predetermined shape on the first lower clad layer, and a predetermined region of the conductive layer A second lower clad layer formed, an active region formed on the second lower clad layer, an upper clad layer formed on the active region, an upper electrode and a conductive layer formed on the upper clad layer and electrically connected to the rest of the conductive layer. A semiconductor light emitting device including a lower electrode formed on an area is provided.

According to another type of the invention, in the semiconductor light emitting device of the horizontal structure having a non-conductive substrate and an n- type semiconductor layer on the non-conductive substrate, a conductive layer having a predetermined shape on the n- type semiconductor layer Forming a layer, regrowing a semiconductor layer of the same type as an n-type semiconductor layer on a conductive layer of a predetermined shape, forming an active region and a p-type semiconductor layer on the regrown semiconductor layer, and p Patterning a -type semiconductor layer and the active region into a predetermined shape until the patterned conductive layer is exposed, forming a p-type electrode on the patterned p-type semiconductor layer, and exposing the patterned conductive layer A method of manufacturing a semiconductor light emitting device is provided, comprising forming an n-type electrode in electrical connection with a layer.

According to another type of the invention, in the semiconductor light emitting device of the horizontal structure having a non-conductive substrate and an n- type semiconductor layer on the non-conductive substrate, a conductive layer having a predetermined shape on the n- type semiconductor layer Forming a patterned layer, etching the n-type semiconductor layer into a trench shape, forming a patterned conductive layer by filling a conductive material to a predetermined height in the trench, regrowing the n-type semiconductor layer, Forming an active region and a p-type semiconductor layer on the regrown n-type semiconductor layer, patterning the p-type semiconductor layer and the active region into a predetermined shape until the patterned conductive layer is exposed; Forming a p-type electrode on the patterned p-type semiconductor layer and forming an n-type electrode in electrical connection with the exposed patterned conductive layer The method of manufacturing a light emitting device is provided.

Hereinafter, with reference to the accompanying drawings will be described in detail a high reflective film electrode structure that can satisfy the low contact resistance and high reflectivity according to the present invention, a semiconductor light emitting device having the same and a method of manufacturing the same in detail. Like reference numerals in the following drawings denote like elements.

2A to 2F are cross-sectional views illustrating a method for manufacturing a semiconductor light emitting device according to a preferred embodiment of the present invention.

First, as shown in FIG. 2A, the first lower clad layer 104 is formed on the transparent substrate 102. In a preferred embodiment of the present invention, the transparent substrate 104 is a sapphire substrate, and the first lower clad layer 104 is formed of n-type AlGaN / GaN. Although not shown in the drawings, a compound semiconductor layer made of GaN-based group III-V nitride compound may be further formed between the transparent substrate 102 and the first lower clad layer 104.

Subsequently, as shown in FIG. 2B, a conductive material is formed on the first lower clad layer 104 and then patterned into a predetermined shape to form the conductive layer 106. According to a preferred embodiment of the present invention, the conductive layer 106 may be formed using doped polysilicon or metal. In addition, according to a preferred embodiment of the present invention, the conductive layer 106 has a thickness of 2,000 kPa to 5,000 kPa.

Next, as shown in FIG. 2C, a second lower clad layer 110 is formed on the patterned conductive layer 106. According to a preferred embodiment of the present invention, the second lower clad layer 110 is grown on the patterned conductive layer 106 by using an epitaxial laterally overgrawn GaN (ELOG) method. Of course, the second lower clad layer 110 is formed of n-type AlGaN / GaN in the same manner as the first lower clad layer 104.

Subsequently, as shown in FIG. 2D, the active region 112 is formed on the second lower clad layer 110, and then the upper clad layer 114 is sequentially formed. According to a preferred embodiment of the present invention, the active region 112 is a material layer in which laser oscillation occurs due to carrier recombination such as electron-holes, and is III- of GaN series having a multi quantum well (MQW) structure. The group V nitride compound semiconductor layer is preferably an InxAlyGa1-x-yN (0 ≦ x ≦ 1, 0 ≦ y ≦ 1 and x + y ≦ 1) layer. In addition, the active layer 108b may be a material layer containing indium (In) in a GaN-based III-V nitride compound semiconductor layer at a predetermined ratio, for example, an InGaN layer.

Subsequently, as shown in FIG. 2E, the upper clad layer 114, the active region 112 and the second lower clad layer 110 are etched until the conductive layer 106 patterned into a predetermined shape is exposed. Define an active area capable of oscillating the laser beam and open the area to form an n-type electrode.

Subsequently, as shown in FIG. 2F, a p-type electrode is formed on the upper clad layer 114 to excite the active region 112 by injecting a current into the active region 112, and exposing it. The n-type electrode 116 is formed on the conductive layer 106. According to a preferred embodiment of the present invention, the p-type electrode 118 may be formed using a conductive material or an alloy thereof having Pd, Ni, Pt, Ag or similar characteristics, and the n-type electrode ( 116 may be formed using a conductive material having Ti, Al or similar properties.

3A is a plan view illustrating an electrode structure formed according to a preferred embodiment of the present invention.

As shown in FIG. 3A, an electrode structure formed according to an embodiment of the present invention includes an n-type electrode 116A and a conductive layer 106A, and the second lower clad layer 110 includes a conductive layer 106A. Regrowth in the midst of According to a preferred embodiment of the present invention, a conductive layer 106A made of a material having a very low electrical resistivity is formed between the first lower clad layer 104 and the second lower clad layer 110. 112) over the entire surface.

Thus, in accordance with a preferred embodiment of the present invention, the conductive layer 106A acts like a current spreading layer that allows current to flow evenly across the active region 112 at the bottom, resulting in the active region 112. The effect of recombination of electrons and holes is evenly distributed over the entire surface.

Therefore, it is possible to implement a structure in which sufficient current can be diffused by only one electrode regardless of the size of the semiconductor device.

3B is a plan view illustrating an electrode structure formed according to another exemplary embodiment of the present invention.

Another preferred embodiment of the present invention shown in FIG. 3B differs from the embodiment shown in FIG. 3A in that the shape of the conductive layer 108B is formed in a stripe shape. However, the conductive layer having the features of the present invention can be modified in various forms such as rectangular or circular.

4 is a cross-sectional view for describing a semiconductor light emitting device according to an embodiment of the present invention.

As shown in FIG. 4, the semiconductor light emitting device 100 is formed on the transparent substrate 102, the first lower clad layer 104 and the first lower clad layer 104 formed on the transparent substrate 102. An electrode structure having a conductive layer 106 and an n-type electrode, a second lower clad layer 110 formed on the conductive layer 106 of the electrode structure, and an active region formed on the second lower clad layer 110 ( 112, an upper clad layer 114 formed on the active region 112, and a p-type electrode 118.

In a preferred embodiment of the present invention, the transparent substrate 104 is formed of a transparent non-conductive material such as sapphire (Al ₂ O ₃ ) or silicon carbide (SiC), the first lower clad layer 104 is n-type AlGaN It was formed with / GaN. Although not shown in the drawings, a compound semiconductor layer made of GaN-based group III-V nitride compound may be further formed between the transparent substrate 102 and the first lower clad layer 104.

According to a preferred embodiment of the present invention, the active region 112 is a material layer in which laser oscillation occurs by carrier recombination such as electron-holes, and III- of GaN series having a multi quantum well (MQW) structure. The group V nitride compound semiconductor layer is preferably an InxAlyGa1-x-yN (0 ≦ x ≦ 1, 0 ≦ y ≦ 1 and x + y ≦ 1) layer. In addition, the active region 112 may be a material layer containing indium (In) in a GaN-based III-V nitride compound semiconductor layer at a predetermined ratio, for example, an InGaN layer.

The p-type electrode 118 may be formed using a conductive material or an alloy thereof having Pd, Ni, Pt, Ag, or similar characteristics, and the n-type electrode 116 may be formed of Ti, Al, or the like. It can be formed using a conductive material having a.

According to a preferred embodiment of the present invention, the conductive layer is preferably formed of a material capable of forming the second lower clad layer 110 by regrowing the same n-type semiconductor as the first lower clad layer 104. It is also preferable to form the ohmic contact with the n-type electrode 116.

Further, according to a preferred embodiment of the present invention, the conductive layer is W, Al, so that the resistivity of the n-type semiconductor layer constituting the first and second lower cladding layer has a value of less than 10 ^-3 Ωcm Mo-based metals or ITO-based highly conductive dielectric films can be used.

5A to 5H are cross-sectional views illustrating a method for manufacturing a semiconductor light emitting device according to another exemplary embodiment of the present invention.

First, as shown in FIG. 5A, the first lower clad layer 204 is formed on the transparent substrate 202. In a preferred embodiment of the present invention, the transparent substrate 204 is a sapphire substrate, and the first lower clad layer 204 is formed of n-type AlGaN / GaN.

Next, as shown in FIG. 5B, the first lower clad layer 204 is patterned to form a trench 205.

Subsequently, as illustrated in FIG. 5C, a conductive material is formed in the trench 205 formed in the first lower clad layer 204 to form a conductive layer 206 patterned into a predetermined shape. According to a preferred embodiment of the present invention, the conductive layer 206 may be formed using doped polysilicon or metal. In addition, according to a preferred embodiment of the present invention, the conductive layer 106 is formed to a thickness of 2,000 kPa to 5,000 kPa.

Subsequently, as shown in FIG. 5D, an auxiliary layer 208 formed of a dielectric material such as SiO ₂ is formed on the patterned conductive layer 206. According to a preferred embodiment of the present invention, the auxiliary layer 208 serves to protect the conductive layer 206 in a subsequent process as well as to facilitate the growth of the second lower clad layer 210 formed thereon. .

Next, as shown in FIG. 5E, a second lower clad layer 210 is formed on the auxiliary layer 208. According to one preferred embodiment of the present invention, the second lower clad layer 210 is grown on the auxiliary layer 208 using the PENDEO epitaxy method. Of course, the second lower clad layer 210 is formed of n-type AlGaN / GaN in the same manner as the first lower clad layer 204.

Subsequent processes shown in FIGS. 5F through 5H are the same as those described with reference to FIGS. 2D through F, and thus detailed descriptions thereof will be omitted.                     

In a preferred embodiment of the present invention, in the embodiment described with reference to Figs. 2A to 2F, the second lower clad layer is grown by using the ELOG method, and the auxiliary layer is not formed, but the second layer is formed by using the PENDEO epitaxy method. It should be noted that the idea of the present invention may be realized by growing the lower clad layer, and also by growing the second lower clad layer using the ELOG method after forming the auxiliary layer.

In addition, according to a preferred embodiment of the present invention, the formation of the pattern of the conductive layer can be variously modified, the structure of the pattern has an area ratio of about 20% to 80% of the total area of the active region is preferred. .

In addition, according to a preferred embodiment of the present invention, the width of the pattern of the conductive layer is preferably formed to have a range of 1 ㎛ to 100 ㎛.

In addition, according to a preferred embodiment of the present invention, the chip can be particularly useful in devices having a size of 0.5 mm ² or more, more effectively applied to the semiconductor light emitting device of the horizontal structure in which the n-type electrode is located at one corner of the device It can be seen.

In addition, according to a preferred embodiment of the present invention, the auxiliary layer may be formed using a material of SiO 2 or SiN, and may be spontaneously formed by adjusting the heat treatment conditions while the conductive layer is regrown.

According to a preferred embodiment of the present invention configured as described above, there is an effect that can provide an n-type electrode structure and a method of manufacturing the same that can spread the current uniformly in the active region.

In addition, according to a preferred embodiment of the present invention, there is an effect that it is possible to provide a semiconductor light emitting device having an n-type electrode structure capable of uniformly spreading current in the active region and a method of manufacturing the same.

In addition, according to a preferred embodiment of the present invention, there is an effect that can reduce the operating voltage by implementing a semiconductor light emitting device having a horizontal structure to solve the current gathering phenomenon that was a problem in the conventional semiconductor light emitting device.

In addition, according to a preferred embodiment of the present invention, even if the distance between the p-type electrode and the n-type electrode can be spread evenly in the active region, since the semiconductor light emitting device suitable for flip chip process has the effect have.

In addition, according to a preferred embodiment of the present invention, since the wafer area can be effectively utilized, the overall yield of the wafer is increased.

In addition, according to a preferred embodiment of the present invention, since the interface between the first lower clad layer and the second lower clad layer is less formed, the scattering effect at the interface of the emission light is reduced to effectively oscillate the laser beam It can be effective.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is in spite of an example, it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention should be determined not by the scope of the detailed description but by the appended claims.

Claims (27)

In a horizontal semiconductor light emitting device having a non-conductive substrate and an n-type semiconductor layer on the non-conductive substrate, An n-type electrode formed in a predetermined region of the n-type semiconductor layer; And a conductive layer formed in the n-type semiconductor layer and electrically connected to the n-type electrode to uniformly diffuse current in the n-type semiconductor layer. The method of claim 1, The conductive layer has an electrode structure, characterized in that the shape of the lattice structure. The method of claim 1, And the conductive layer has a stripe structure. The method of claim 1, And an auxiliary layer on the conductive layer to protect the conductive layer and to easily grow a subsequently formed layer. The method according to any one of claims 1 to 4, Electrode structure, characterized in that to form the conductive layer using a doped polysilicon. The method according to any one of claims 1 to 4, And the conductive layer is formed using a metal selected from the group consisting of W, Al, and Mo. The method according to any one of claims 1 to 4, The conductive structure is formed to have a thickness of 2,000 kPa to 5,000 kPa. The method according to any one of claims 1 to 4, The width of the pattern of the conductive layer is formed to have a range of 1 ㎛ to 100 ㎛ electrode structure. Non-conductive substrate; A first lower clad layer formed on the non-conductive substrate; A conductive layer having a predetermined shape on the first lower clad layer; A second lower clad layer formed on a predetermined region of the conductive layer; An active region formed on the second lower clad layer; An upper clad layer formed on the active region; An upper electrode formed on the upper clad layer; And And a lower electrode electrically connected to the conductive layer and formed on the remaining area of the conductive layer. The method of claim 9, And the conductive layer has a lattice structure. The method of claim 9, And the conductive layer has a stripe structure. The method of claim 9, And an auxiliary layer on the conductive layer to protect the conductive layer and to easily grow a subsequently formed layer. The method according to any one of claims 9 to 12, A semiconductor light emitting device, characterized in that the conductive layer is formed using a doped polysilicon. The method according to any one of claims 9 to 12, The conductive layer is formed using a metal selected from the group consisting of W, Al, and Mo. The method according to any one of claims 9 to 12, And the conductive layer is formed to have a thickness of 2,000 kPa to 5,000 kPa. The method according to any one of claims 9 to 12, The width of the pattern of the conductive layer is formed to have a range of 1 ㎛ to 100 ㎛ semiconductor light emitting device. In the method for manufacturing a semiconductor light emitting device having a horizontal structure comprising a non-conductive substrate and an n- type semiconductor layer on the non-conductive substrate, Forming a conductive layer having a predetermined shape on the n-type semiconductor layer; Regrowing a semiconductor layer of the same type as the n-type semiconductor layer on the conductive layer of the predetermined shape; Forming an active region and a p-type semiconductor layer on the regrown semiconductor layer; Patterning the p-type semiconductor layer and the active region into a predetermined shape until the patterned conductive layer is exposed; Forming a p-type electrode on the patterned p-type semiconductor layer; And And forming an n-type electrode to be electrically connected to the exposed patterned conductive layer. The method of claim 17, Wherein the regrowth step is performed by an ELOG method. In the method for manufacturing a semiconductor light emitting device having a horizontal structure comprising a non-conductive substrate and an n- type semiconductor layer on the non-conductive substrate, Forming a conductive layer having a predetermined shape on the n-type semiconductor layer; Etching the n-type semiconductor layer into a trench shape; Forming a patterned conductive layer by filling the trench to a predetermined height in the trench; Regrowing the n-type semiconductor layer; Forming an active region and a p-type semiconductor layer on the regrown n-type semiconductor layer; Patterning the p-type semiconductor layer and the active region into a predetermined shape until the patterned conductive layer is exposed; Forming a p-type electrode on the patterned p-type semiconductor layer; And And forming an n-type electrode to be electrically connected to the exposed patterned conductive layer. The method of claim 19, And wherein said regrowth step is performed by a PENDEO epitaxy method. The method according to any one of claims 17 to 20, And forming an auxiliary layer on the patterned conductive layer so as to protect the conductive layer and to easily grow a subsequently formed layer. The method according to any one of claims 17 to 20, And the patterned conductive layer has a lattice structure. The method according to any one of claims 17 to 20, And the patterned conductive layer has a stripe structure. The method according to any one of claims 17 to 20, The conductive layer is formed using a doped polysilicon method for producing a semiconductor light emitting device. The method according to any one of claims 17 to 20, The conductive layer is formed by using a metal selected from the group consisting of W, Al, and Mo. The method according to any one of claims 17 to 20, The conductive layer is formed to have a thickness of 2,000 kV to 5,000 kV. The method according to any one of claims 17 to 20, The width of the pattern of the conductive layer is formed to have a range of 1 ㎛ to 100 ㎛ method for manufacturing a semiconductor light emitting device.

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