KR20120135818A - Light emitting device and manufacturing method of the same - Google Patents

Abstract

PURPOSE: A light emitting device and a manufacturing method thereof are provided to reduce current density by preventing current flow between a second electrode and an active layer to be crowded in a partial region of a second semiconductor region. CONSTITUTION: A photoelectric layer(120) comprises a first semiconductor layer, an active layer, and a second semiconductor layer. A current blocking layer(130) is concavely formed at a part of the surface of second semiconductor layer. The current blocking layer has charge mobility lower than the second semiconductor layer. An ohmic contact layer(140) is evenly formed on the second semiconductor layer with transparent conductive material. A first electrode is formed on a partial region of the first semiconductor layer.

Description

LIGHT EMITTING DEVICE AND MANUFACTURING METHOD OF THE SAME

The present invention relates to a light emitting device that emits light and a method of manufacturing the same, and more particularly, to a light emitting device capable of reducing current density and a method of manufacturing the same.

A light emitting device (LED) includes a photoelectric layer composed of a plurality of p-n bonded semiconductor layers and converts electrical energy into optical energy to emit light.

Such a light emitting device has an advantage of having high energy efficiency since it can emit light of high brightness at low voltage, compared to other devices that emit light. In particular, when the photoelectric layer is formed of a gallium nitride (GaN) -based nitride semiconductor, the light emitting device can emit light in a wide range of wavelengths, including infrared to infrared. Accordingly, the light emitting device may be variously applied to various automation devices such as a backlight unit, a display board, a display, and a home appliance of a liquid crystal display, and may be used for environmentally harmful substances such as arsenic (As) and mercury (Hg). Since it does not include, it has been spotlighted as a next-generation light source.

A typical light emitting device includes at least a photoelectric layer including an n-type semiconductor layer, an active layer and a p-type semiconductor layer sequentially stacked on a substrate, an ohmic contact layer formed on a p-type semiconductor layer, and an n-type semiconductor layer. And a first electrode formed to be in contact with a portion to inject electrons into the n-type semiconductor layer, and a second electrode formed on the ohmic contact layer to inject holes into the p-type semiconductor layer. In this case, the second electrode may be formed in direct contact with the p-type semiconductor layer through a contact hole penetrating the ohmic contact layer.

However, the holes injected through the second electrode tend to move in the path of the least resistance, and thus are concentrated in a partial region corresponding to the lower portion of the second electrode of the p-type semiconductor layer. That is, a phenomenon in which the current flow between the second electrode and the active layer due to the hole movement is not dispersed in a wide area as much as possible of the p-type semiconductor layer and is concentrated only on a partial region of the p-type semiconductor layer (hereinafter referred to as "current density phenomenon"). ) Is generated.

At this time, the higher the current density (here, “current density refers to the degree of the current density”), the more the holes injected through the second electrode do not reach the active layer and accumulate or disappear more in the area outside the active layer, thus, luminous efficiency (Here, "luminescence efficiency" means a rate at which holes and electrons injected into the device are converted to light). In addition, holes accumulated in regions other than the active layer are converted into thermal energy to generate high temperature heat in the device, thereby reducing the lifetime of the device and deteriorating reliability due to deterioration.

The present invention includes a current blocking layer that is formed concave on the photoelectric layer so as not to form a step in the ohmic contact layer, and can reduce the current density, while also improving the contact resistance between the ohmic contact layer and the electrode. An object and a manufacturing method thereof are provided.

In order to solve such a problem, the present invention is a substrate; A photovoltaic layer including a first semiconductor layer, an active layer, and a second semiconductor layer sequentially stacked on the substrate; A current blocking layer recessed in a portion of the surface of the second semiconductor layer, the current blocking layer having a lower charge mobility than the second semiconductor layer; An ohmic contact layer formed flat on the second semiconductor layer including the current blocking layer with a transparent conductive material; A first electrode formed on a portion of the first semiconductor layer exposed by removing portions of each of the ohmic contact layer, the second semiconductor layer, and the active layer; And a second electrode formed on the ohmic contact layer and at least partially overlapping the current blocking layer.

In addition, the present invention comprises the steps of stacking a plurality of semiconductor layers including a first semiconductor layer, an active layer and a second semiconductor layer on a substrate, to form a photoelectric layer; Oxidizing a part of the surface of the second semiconductor layer to form a concave current blocking layer having a lower charge mobility than the second semiconductor layer on the surface of the second semiconductor layer; Stacking a transparent conductive material on the second semiconductor layer including the current blocking layer to form an ohmic contact layer; Removing a portion of each of the ohmic contact layer, the second semiconductor layer, and the active layer to expose a portion of the first semiconductor layer; And forming a first electrode in contact with a portion of the exposed first semiconductor layer and a second electrode at least partially overlapping the current blocking layer on the ohmic contact layer. to provide.

As described above, the light emitting device according to the present invention is formed concave on a part of the surface of the photoelectric layer, the second semiconductor layer comprising a plurality of semiconductor layers including a first semiconductor layer, an active layer and a second semiconductor layer stacked on a substrate. A current blocking layer having a lower charge mobility than the second semiconductor layer, a first electrode formed in contact with a portion of the first semiconductor layer, and a second electrode formed on the ohmic contact layer and at least partially overlapping the current blocking layer. Include.

As described above, since the current blocking layer has a lower charge mobility than the second semiconductor layer and is disposed between the active layer and the second electrode, holes injected through the second electrode are directed to the active layer, avoiding the current blocking layer. In this case, the current flow in the second semiconductor layer may be wider than in the related art. That is, the current flow between the second electrode and the active layer due to the hole movement may be minimized in the partial region of the second semiconductor layer corresponding to the lower portion of the second electrode. Therefore, current density can be reduced, so that luminous efficiency can be improved.

And, since the current blocking layer is formed concave on the surface of the second semiconductor layer, the upper portion of the second semiconductor layer including the current blocking layer is flat, so that the ohmic contact layer formed thereon does not include the step by the current blocking layer. Can be formed flat. Accordingly, the bonding surface between the ohmic contact layer and the second semiconductor layer is flat, thereby preventing the ohmic contact layer and the second semiconductor layer from being easily separated and preventing contact failure between the two.

In addition, according to the present invention, the current blocking layer oxidizes a part of the p-type nitride semiconductor constituting the second semiconductor layer, and has gallium oxide (Ga _x O _y , 0 <x, y) having a refractive index of about 1.8 to 1.9. As a result, the difference in refractive index between the current blocking layer and the second semiconductor layer is smaller than that of the conventional method of forming the current blocking layer with silicon oxide (SiO ₂ ) having a refractive index of about 1.46. Therefore, the critical angle is increased at the interface between the current blocking layer and the second semiconductor layer, so that the totally reflected light is reduced, so that the light extraction efficiency of the device (here, "light extraction efficiency") is that light generated in the active layer is emitted to the outside. Ratio) can be improved.

In addition, according to the present invention, since the current blocking layer oxidizes a part of the p-type nitride semiconductor constituting the second semiconductor layer and is formed concave on the surface of the second semiconductor layer, the second semiconductor is as deep as the current blocking layer is formed. The thickness of the layer becomes low. Accordingly, holes accumulated in the second semiconductor layer corresponding to the lower portion of the current blocking layer and accumulated or lost are reduced, and the effective holes (here, the "effective holes" form electron-hole pairs together with the electrons reaching the active layer. It means that the hole can be increased), the luminous efficiency can be improved.

In addition, according to the present invention, since a part of the surface of the second semiconductor layer is wet oxidized to form a current blocking layer without being exposed to the plasma gas, damage to the photoelectric layer due to exposure to the plasma gas can be prevented.

1 is a cross-sectional view showing a light emitting device according to an embodiment of the present invention.
2 is a cross-sectional view showing a light emitting device according to another embodiment of the present invention.
3A and 3B illustrate a first comparative example which does not include a current blocking layer and a current blocking layer that is formed as a separate layer on the second semiconductor layer, unlike in the embodiment or the other embodiment of the present invention. It is sectional drawing which showed the comparative example.
4A and 4B show light distribution images according to the first comparative example shown in FIG. 3A and the embodiment of the present invention shown in FIG. 1.
5 is a flowchart illustrating a method of manufacturing a light emitting device according to an embodiment of the present invention.
6A to 6F are process charts showing the manufacturing method of the light emitting device shown in FIG.

Hereinafter, a 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.

First, a light emitting device according to an exemplary embodiment of the present invention will be described with reference to FIGS. 1, 2, 3A, 3B, 4A, and 4B.

1 is a cross-sectional view showing a light emitting device according to an embodiment of the present invention, Figure 2 is a cross-sectional view showing a light emitting device according to another embodiment of the present invention. 3A and 3B illustrate a first comparative example which does not include a current blocking layer and a current blocking layer that is formed as a separate layer on the second semiconductor layer, unlike in the embodiment or the other embodiment of the present invention. It is sectional drawing which showed the comparative example. 4A and 4B show light distribution images according to the first comparative example shown in FIG. 3A and the embodiment of the present invention shown in FIG. 1.

As shown in FIG. 1, the light emitting device 100 according to the exemplary embodiment of the present invention may be undoped to be sequentially stacked on the substrate 110, the buffer layer 111 formed on the substrate 110, and the buffer layer 111. It is formed concave on a part of the surface of the photoelectric layer 120, the second semiconductor layer 124 including the semiconductor layer 121, the first semiconductor layer 122, the active layer 123 and the second semiconductor layer 124, The ohmic contact layer 140 is formed of a transparent conductive material on the second semiconductor layer 124 including the current blocking layer 130 and the current blocking layer 130 having a lower charge mobility than the second semiconductor layer 124. do. The first electrode 151 is formed in contact with a partial region of the first semiconductor layer 122 exposed by removing partial regions of the ohmic contact layer 140, the second semiconductor layer 124, and the active layer 123. And a second electrode 152 formed on the ohmic contact layer 140 and at least partially overlapping the current blocking layer. In addition, the semiconductor device may further include a contact hole 141 penetrating the ohmic contact layer 140 to expose at least a portion of the current blocking layer 130, and a portion of the second electrode 152 is exposed through the contact hole 141. It may be in direct contact with at least a portion of the current blocking layer 130.

The substrate 110 may be selected from Al ₂ O ₃ (Sapphire: Sapphire), SiC, and AlN having a crystal structure similar to GaN, GaN-based, and GaN. In particular, the substrate 110 may be selected as a sapphire (Al ₂ O ₃ ) substrate having the advantages of low cost, low strain due to alkali or acid, and low strain due to heat.

The buffer layer 111 is a buffer layer for reducing crystal defects of the photoelectric layer 120 generated due to the difference in lattice constant and thermal expansion coefficient between the substrate 110 and the photoelectric layer 120. That is, when the substrate 110 and the photoelectric layer 120 are not selected as the same material, the lattice constant and thermal expansion coefficient of the semiconductor material forming the photoelectric layer 120 are different from those of the substrate 110. Crystal defects are generated in the semiconductor material grown on the (110), and the crystal defects at this time interfere with the current flow of the device, in order to minimize this, the buffer layer 111 between the substrate 110 and the photoelectric layer 120 Is formed. Accordingly, when the substrate 110 and the photoelectric layer 120 are selected as the same material, or when the difference in lattice constant and thermal expansion coefficient between the substrate 110 and the photoelectric layer 120 is less than a threshold, the buffer layer 111 is used. This may be excluded. The buffer layer 111 may be formed of thinly stacked SiOx or SiNx, or a low temperature grown semiconductor material.

The undoped semiconductor layer 121 of the photoelectric layer 120 is formed by stacking a semiconductor material not doped with impurities on the substrate 110 or on the substrate 110 including the buffer layer 111.

The first semiconductor layer 122 is formed by stacking an n-type semiconductor doped with n-type impurities to increase electron mobility on the undoped semiconductor layer 121. In this case, the n-type impurity may be Si.

The active layer 123 is formed by stacking a semiconductor having a quantum well structure on the first semiconductor layer 122. In the active layer 123, electrons and holes injected through the first electrode 151 and the second electrode 152 meet and recombine to generate excitons, and the excitons at this time are in an excited state in an excited state. Light is generated from the extra energy generated by falling to the ground state.

The second semiconductor layer 124 is formed by stacking a p-type semiconductor doped with a p-type impurity to increase hole mobility on the active layer 123. In this case, the p-type impurity may be Mg.

In particular, the photoelectric layer 120 may be formed of a gallium nitride (GaN) -based semiconductor material.

In this case, the first semiconductor layer 122 is formed of an n-type nitride semiconductor doped with n-type impurities such as Si, and the second semiconductor layer 124 is p- doped with p-type impurities such as Mg. It is formed as a type nitride semiconductor.

Then, the active layer 123 has a single quantum well structure or a multiple quantum well made of a well layer of In _x (Al _y Ga _(1-y)) N in the barrier layer and the In _x (Al _y Ga _(1-y)) N It may be formed into a structure (MQW). In this case, according to the composition ratio of the nitride semiconductors (InGaN, GaN) of the barrier layer and the well layer, the wavelength region of the light emitted from the light emitting device is freely determined from the long wavelength to the short wavelength having the AlN (˜6.4 eV) band gap.

Meanwhile, the photoelectric layer 120 may be formed by growing a semiconductor material by using a metal organic chemical vapor deposition (MOCVD) method.

The current blocking layer 130 is formed by oxidizing a part of the surface of the second semiconductor layer 124. That is, the current blocking layer 130 is formed of an oxidized part of the surface of the second semiconductor layer 124.

In this case, the second semiconductor layer 124 is formed of a p-type nitride semiconductor (p-GaN), and the current blocking layer 130 is formed of gallium oxide (Ga _x O _y , 0 <x, y). Alternatively, the current blocking layer 130 may be formed of gallium oxide (Metal-Contained Ga _x O _y , 0 <x, y) including any one metal of Al, In, Si, and Mg.

In particular, the current blocking layer 130 is formed by wet oxidation of a part of the surface of the second semiconductor layer 124. In this case, the wet oxidation of a part of the surface of the second semiconductor layer 124 is performed by dipping the photoelectric layer 120 stacked on the substrate 110 in deionized water, and deionized water and the second semiconductor layer. The cathodes and the anodes are respectively connected to 124, and a portion of the surface of the second semiconductor layer 124 to form the current blocking layer 130 is selectively irradiated with light energy. This will be described in more detail with reference to FIG. 6B below.

The ohmic contact layer 140 is to diffuse the holes injected through the second electrode 152 to the second semiconductor layer 124 as wide as possible, and the current blocking layer 130 is disposed on the second semiconductor layer 124. It is formed to cover. The ohmic contact layer 140 may be selected as a transparent conductive material, and in particular, metal oxides of any one of SnO ₂ , ZnO, In ₂ O ₃ and TiO ₂ and these metal oxides may be selected from F, Sn, Al, Fe, At least one of Ga and Nb may be selected as the doped material.

The first electrode 151 contacts a partial region of the first semiconductor layer 122 exposed to the outside by removing partial regions of each of the ohmic contact layer 140, the second semiconductor layer 124, and the active layer 123. Is formed.

The second electrode 152 is formed to at least partially overlap the current blocking layer 130 on the ohmic contact layer 140. In this case, the second electrode 152 is formed in contact with at least a portion of the current blocking layer 130 through a contact hole 141 that penetrates the ohmic contact layer 140 and exposes at least a portion of the current blocking layer 130. Can be. As a result, the contact surface between the second electrode 152 and the ohmic contact layer 140 increases, so that holes injected into the second electrode 152 do not accumulate on the upper surface of the ohmic contact layer 140. May move more to layer 120.

Or, as shown in Figure 2, according to another embodiment of the present invention, when the charge mobility of the ohmic contact layer 140 is sufficiently high, the contact hole (not shown) is excluded, the second electrode 152 ' ) May be formed only on the ohmic contact layer 140.

The first and second electrodes 151 and 152 may be formed of the same or different conductive materials. In particular, the first and second electrodes 151 and 152 may include at least one metal or two or more of Ni, Au, Pt, Ti, Al, and Cr. It may be selected as a laminated structure or an alloy.

Meanwhile, as shown by the dotted arrow in FIG. 3A, in the first comparative example 10, the ohmic contact layer 12 formed on the second semiconductor layer 11 of the photoelectric layer without the current blocking layer is included. ), A contact hole 13 penetrating the ohmic contact layer 12 and a second electrode 14 formed on the ohmic contact layer 12 and contacting the second semiconductor layer 11 through the contact hole 13. In this case, since the holes injected through the second electrode 14 try to move only in the path of the minimum resistance, the current is concentrated in the partial region of the second semiconductor layer 11 corresponding to the lower portion of the second electrode 14. Done.

On the contrary, the light emitting devices 100 and 100 ′ according to the embodiments of the present invention and the other embodiments include the current blocking layer 130 formed of an oxidized part of the surface of the second semiconductor layer 124. In this case, the current blocking layer 130 is formed concave on the surface of the second semiconductor layer 124 and has a lower charge mobility than the second semiconductor layer 124. Accordingly, as shown by the dotted arrows in FIGS. 1 and 2, holes injected through the second electrode 152 move in a path to avoid the current blocking layer 130 having a low charge mobility. The current may spread to a wide area of the second semiconductor layer 124. That is, since the current density decreases, holes lost or accumulated in the region other than the active layer 123 are reduced, and thus effective holes are increased, thereby improving luminous efficiency.

4A and 4B, while the light distribution image (FIG. 4A) according to the first comparative example 10 shows a light green color in the dotted circle region, the light distribution image according to the embodiment of the present invention (FIG. 4B). ) Represents yellow, which means higher light emission than light green. As a result, it is confirmed that the luminous efficiency is improved by the current blocking layer 130.

In addition, as shown in FIG. 3B, in the second comparative example 20, the current blocking layer 22 formed of a separate silicon oxide (SiO ₂ ) layer on the second semiconductor layer 21 of the photoelectric layer. , Ohmic contact layer 23 formed on second semiconductor layer 21 including current blocking layer 22, contact hole 24 passing through ohmic contact layer 23, and ohmic contact layer 23. The second electrode 25 is formed to overlap at least a portion of the current blocking layer 22 and contacts the current blocking layer 22 through the contact hole 24. That is, since the second comparative example 20 includes the current blocking layer 22, unlike the first comparative example 10, the current flow may be wider than that of the first comparative example 10.

However, in the case of the second comparative example 20, the cross-sectional shape of the ohmic contact layer 23 includes the step as the current blocking layer 22 is formed convexly on the second semiconductor layer 21. Due to this step, the depth Dch_ref2 (ref2 contact hole Depth) of the contact hole 24 increases, and the ohmic contact layer 23 and the second electrode 25 are increased by the increased depth Dch_ref2 of the contact hole 24. The contact resistance between) may increase unnecessarily. In addition, since the contact surface between the ohmic contact layer 23 and the second semiconductor layer 21 is not flat, the ohmic contact layer 23 and the second semiconductor layer 21 can be easily separated. Poor contact may occur between them.

In addition, as shown by the dotted arrows in FIG. 3B, in the case of the second comparative example 20, the second semiconductor layer 21 is irrespective of whether or not the current blocking layer 22 is present thereon. It is formed with the same thickness THp_ref2 (ref2 p-GaN THickness). Accordingly, some of the holes injected through the second electrode 25 may flow back to the second semiconductor layer 21 under the current blocking layer 22 in a path avoiding the current blocking layer 22. As the effective hole is reduced, the luminous efficiency may be reduced.

On the contrary, according to the embodiment of the present invention and the other embodiments, since the current blocking layer 130 is formed concave as an oxidized part of the surface of the second semiconductor layer 124, the second including the current blocking layer 130 The upper portion of the semiconductor layer 124 has the same flat surface regardless of whether the current blocking layer 130 is formed. Accordingly, the ohmic contact layer 140 formed on the second semiconductor layer 124 has a uniform thickness without a step, and the depth Dch of the contact hole 141 is equal to the thickness of the ohmic contact layer 140. Therefore, it is possible to prevent the contact resistance between the ohmic contact layer 140 and the second electrode 152 from increasing unnecessarily. In addition, the contact surface between the ohmic contact layer 140 and the second semiconductor layer 124 is flat, so that the two can be easily separated, and the contact failure between the two can be prevented.

1 and 2, since the current blocking layer 130 is formed of an oxidized part of the surface of the second semiconductor layer 124, according to an embodiment of the present invention and another embodiment, The thickness THp of the second semiconductor layer 124 is reduced by the depth of the current blocking layer 130. That is, since the p-type nitride semiconductor corresponding to the lower portion of the current blocking layer 130 is smaller than other regions, holes that accumulate or disappear due to flow to the second semiconductor layer 124 under the current blocking layer 130 may be reduced. And, the effective hole can be increased by that, the luminous efficiency can be improved.

In addition, in the second comparative example 20, the current blocking layer 22 is made of silicon oxide (SiO ₂ ) having a refractive index of about 1.46, whereas the current blocking layer according to the embodiment of the present invention and other embodiments The layer 130 is made of gallium oxide (Ga _x O _y ) having a refractive index of about 1.8 to 1.9. That is, according to the embodiment of the present invention and another embodiment, the difference in refractive index between the current blocking layer 130 and the second semiconductor layer 124 made of a nitride semiconductor having a refractive index of about 2 or more is the second comparative example 20 Since it is lower, the critical angle is increased so that light totally reflected at the interface between the second semiconductor layer 124 and the current blocking layer 130 is reduced, so that the light extraction efficiency can be improved than that of the second comparative example 20. Can be.

Next, a method of manufacturing a light emitting device according to an embodiment of the present invention will be described with reference to FIGS. 5 and 6A to 6F.

5 is a flowchart illustrating a manufacturing method of a light emitting device according to an exemplary embodiment of the present invention, and FIGS. 6A to 6F are flowcharts illustrating a manufacturing method of the light emitting device shown in FIG. 5.

As shown in FIG. 5, in the method of manufacturing a light emitting device according to an embodiment of the present invention, forming a photoelectric layer by stacking a first semiconductor layer, an active layer, and a second semiconductor layer on a substrate (S100). Oxidizing a part of the surface of the second semiconductor layer to form a concave current blocking layer having a lower charge mobility than that of the second semiconductor layer on the surface of the second semiconductor layer (S110), on the second semiconductor layer including the current blocking layer; Stacking a transparent conductive material on the substrate to form an ohmic contact layer (S120), removing a partial region of each of the ohmic contact layer, the second semiconductor layer, and the active layer to expose a partial region of the first semiconductor layer (S130), And forming a first electrode in contact with a portion of the exposed first semiconductor layer and a second electrode at least partially overlapping the current blocking layer on the ohmic contact layer (S140).

As shown in FIG. 6A, in the forming of the photoelectric layer 120 (S100), the first semiconductor layer 122 is formed of an n-type semiconductor doped with n-type impurities on the substrate 110. Forming an active layer 123 with a nitride semiconductor having a quantum well structure on the first semiconductor layer 122 and a second semiconductor layer 124 having a p-type semiconductor doped with p-type impurities on the active layer 123. Forming a step). In this case, in the forming of the photoelectric layer 120 (S100), before the forming of the first semiconductor layer 122, a nitride semiconductor not doped with impurities is stacked on the substrate 110, thereby forming an undoped semiconductor layer. The method may further include forming 121.

In addition, when the substrate 110 and the photoelectric layer 120 are heterogeneous materials, before forming the photoelectric layer 120 (S100), SiOx or SiNx that is finely stacked on the substrate 110 or low temperature growth may be used. The method may further include forming the buffer layer 111 using the semiconductor material. In this case, the forming of the buffer layer 111 may be performed in an atmosphere including low-temperature heat mainly growing the semiconductor material in a direction parallel to the growth surface.

The forming of the undoped semiconductor layer 121, the forming of the first semiconductor layer 122, the forming of the active layer 123, and the forming of the second semiconductor layer 124 each include a semiconductor material. It is carried out in an atmosphere containing high temperature heat which is mainly grown along the direction perpendicular to the growth plane. For example, when the step (S100) of forming the photoelectric layer 120 is performed by a metal organic chemical vapor deposition (MOCVD) method, the high temperature corresponds to 700 degrees Celsius to 1200 degrees Celsius, and the low temperature is 500 degrees Celsius to It may correspond to 700 degrees Celsius.

As illustrated in FIG. 6B, the forming of the current blocking layer 130 (S110) is performed by wet oxidation of a part of the surface of the second semiconductor layer 124. That is, in the state in which the photoelectric layer 120 stacked on the substrate 110 is immersed in deionized water 210 accommodated in the received water tank 211, the deionized water 210 and the second semiconductor layer 124 are immersed. The cathode 221 (-) and the anode 222 (+) are connected to form an electric field therebetween, and the current blocking layer is formed on the surface of the second semiconductor layer 124 by using the light blocking mask 230. Light energy LIGHT is selectively applied on the region to form 130. In this case, the light energy LIGHT may be ultraviolet (UV) ionizing water (H ₂ O) of the deionized water 210 with hydrogen ions (2H ⁺ ) and oxygen ions (O ⁻ ).

In this way, holes are accumulated on the surface of the second semiconductor layer 124 due to the electric field between the deionized water 210 and the second semiconductor layer 124, and thus, p − in the region exposed to the light energy LIGHT. Nitrogen (N) of the type nitride semiconductor (p-GaN) is easily substituted with oxygen ions (O ⁻ ) of the deionized water 210, thereby exposing a portion of the surface of the second semiconductor layer 124 exposed to light energy LIGHT. Is oxidized. Accordingly, as shown in FIG. 6C, a current blocking layer 130 of gallium oxide (Ga _x O _y , 0 <x, y) is formed concave on a part of the surface of the second semiconductor layer 124.

Alternatively, by adding a metal element of any one of Al, In, Si, and Mg to the deionized water 210, the current blocking layer 130 is gallium oxide (Ga) containing any one of Al, In, Si and Mg. _x O _y , 0 <x, y).

Subsequently, as illustrated in FIG. 6D, the transparent conductive material is stacked on the second semiconductor layer 124 including the current blocking layer 130 to form an ohmic contact layer 140 (S120).

As shown in FIG. 6E, partial regions of the ohmic contact layer 140, the second semiconductor layer 124, and the active layer 123 are removed to expose a portion of the first semiconductor layer 122 (S130). . In this case, another partial region of the ohmic contact layer 140 may be removed to further form a contact hole 141 exposing at least a portion of the current blocking layer 130.

And, as shown in Figure 6f, a metal layer selected from any one of the metals of Ni, Au, Pt, Ti, Al and Cr or two or more laminated or alloy is laminated, patterned, and exposed A first electrode 151 is formed on a portion of the first semiconductor layer 131, and a second electrode 152 is formed on the ohmic contact layer 140 at least partially overlapping the current blocking layer 130. do. (S140)

Steps S100 to S150 are simultaneously performed on a plurality of chips on the wafer. When the formation of the first and second electrodes 151 and 152 (S140) is completed, the chips are separated into individual chips.

As described above, according to the embodiment of the present invention, in order to form the current blocking layer 130 with the oxidized part of the surface of the second semiconductor layer 124, the surface of the second semiconductor layer 124 is treated with an oxygen plasma gas. Instead, it is treated by wet oxidation. Accordingly, since the photoelectric layer 120 may not be chemically or physically damaged by the plasma gas, it is possible to prevent a decrease in reliability of the device.

The present invention described above is not limited to the above-described embodiment and the accompanying drawings, and various substitutions, modifications, and changes may be made without departing from the technical spirit of the present invention.

100, 100 ': light emitting element 110: substrate
111: buffer layer 120: photoelectric layer
121: undoped semiconductor layer 122: first semiconductor layer
123: active layer 124: second semiconductor layer
130: current blocking layer 140: ohmic contact layer
141: contact holes 151 and 152: first and second electrodes
210: deionized water 221, 222: cathode, anode
230: light blocking mask

Claims (14)

Board;
A photovoltaic layer including a first semiconductor layer, an active layer, and a second semiconductor layer sequentially stacked on the substrate;
A current blocking layer recessed in a portion of the surface of the second semiconductor layer, the current blocking layer having a lower charge mobility than the second semiconductor layer;
An ohmic contact layer formed flat on the second semiconductor layer including the current blocking layer with a transparent conductive material;
A first electrode formed on a portion of the first semiconductor layer exposed by removing portions of each of the ohmic contact layer, the second semiconductor layer, and the active layer; And
And a second electrode formed on the ohmic contact layer and at least partially overlapping the current blocking layer. The method of claim 1,
The first semiconductor layer is formed of an n-type nitride semiconductor doped with a first impurity,
The active layer is formed of a nitride semiconductor of quantum well structure,
And the second semiconductor layer is formed of a p-type nitride semiconductor doped with a second impurity. The method of claim 2,
The current blocking layer is formed of gallium oxide (Ga _x O _y , 0 <x, y) by oxidizing a part of the surface of the second semiconductor layer. The method of claim 3,
The current blocking layer is a light emitting device formed of gallium oxide containing any one metal of Al, In, Si and Mg. The method of claim 2,
The photovoltaic layer further comprises an undoped semiconductor layer formed of a nitride semiconductor that is not doped with impurities between the substrate and the first semiconductor layer. The method of claim 1,
A portion of the second electrode is in contact with at least a portion of the current blocking layer exposed through the contact hole penetrating the ohmic contact layer. Stacking a plurality of semiconductor layers including a first semiconductor layer, an active layer, and a second semiconductor layer on a substrate to form a photoelectric layer;
Oxidizing a part of the surface of the second semiconductor layer to form a concave current blocking layer having a lower charge mobility than the second semiconductor layer on the surface of the second semiconductor layer;
Stacking a transparent conductive material on the second semiconductor layer including the current blocking layer to form an ohmic contact layer;
Removing a portion of each of the ohmic contact layer, the second semiconductor layer, and the active layer to expose a portion of the first semiconductor layer; And
Forming a first electrode in contact with a portion of the exposed first semiconductor layer and a second electrode at least partially overlapping the current blocking layer on the ohmic contact layer. The method of claim 7, wherein
Forming the photoelectric layer is
Stacking an n-type nitride semiconductor doped with a first impurity on the substrate to form the first semiconductor layer;
Stacking a nitride semiconductor having a quantum well structure on the first semiconductor layer to form the active layer; And
Stacking a p-type nitride semiconductor doped with a second impurity on the active layer to form the second semiconductor layer. 9. The method of claim 8,
Forming the current blocking layer,
In the state in which the photoelectric layer formed on the substrate is immersed in deionized water,
By forming an electric field between the deionized water and the second semiconductor layer, selectively applying light energy to a part of the surface of the second semiconductor layer,
Wet manufacturing method comprising the step of performing a wet oxidation on a portion of the surface of the second semiconductor layer. 10. The method of claim 9,
In the step of performing the wet oxidation,
The deionized water is connected to the cathode, the second semiconductor layer is connected to the anode, an electric field generated between the deionized water and the second semiconductor layer, holes are accumulated on the surface of the second semiconductor layer,
The light energy is water (H ₂ O) of the deionized water protons (2H ⁺⁾ and oxygen ^{ion-manufacturing} method of an ultraviolet (UV) light-emitting device of the ionized (O). The method of claim 10,
In the step of forming the current blocking layer,
On part of the surface of the second semiconductor layer, nitrogen (N) of the p-type nitride semiconductor (p-GaN) is replaced with the oxygen ions (O ⁻ ), so that gallium oxide (Ga _x O _y , 0 <x, y) manufacturing method of the light emitting element formed. The method of claim 11,
In the step of forming the current blocking layer,
The deionized water includes any one metal of Al, In, Si, and Mg,
The current blocking layer is a method of manufacturing a light emitting device formed of gallium oxide (Ga _x O _y , 0 <x, y) containing any one metal of Al, In, Si and Mg. 9. The method of claim 8,
Forming the photoelectric layer,
And forming an undoped semiconductor layer by stacking a nitride semiconductor not doped with impurities on the substrate before forming the first semiconductor layer. The method of claim 7, wherein
Before forming the first electrode and the second electrode,
Penetrating a portion of the ohmic contact layer to form a contact hole exposing at least a portion of the current blocking layer,
And a part of the second electrode is in contact with at least a part of the current blocking layer through the contact hole.

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