KR20120132291A - 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 prevent the deterioration of luminous efficiency due to the increase of a removal area of an active layer by increasing a contact area between a first semiconductor layer and a first electrode without increasing a width of a first groove. CONSTITUTION: A photoelectric layer(140) includes a first semiconductor layer(141), an active layer(142), and a second semiconductor layer(143) which are successively laminated on a substrate. An ohmic contact layer(150) is made of transparent conductive materials and is formed on the second semiconductor layer. A first groove(160) partially passes through the ohmic contact layer, the second semiconductor layer, and the active layer. A second groove(170) passes through a part of the first semiconductor layer. A first electrode(181) is contacted with a second region of the first semiconductor layer. A second electrode(182) is formed on a part of the ohmic contact layer.

Description

LIGHT EMITTING DEVICE AND MANUFACTURING METHOD OF THE SAME

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device for converting electrical energy into light energy, and in particular, a lateral light emitting device (Lateral Light Emitting Device: Lateral LED) including first and second electrodes disposed side by side on a light emitting surface and It relates to a manufacturing method.

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 general light emitting device includes an optoelectronic 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 electron in an n-type semiconductor layer. And a second electrode for injecting holes into the p-type semiconductor layer.

Such a light emitting device has a vertical type (hereinafter, referred to as a “vertical light emitting device”) including first and second electrodes disposed in a direction perpendicular to the light emitting surface, and in a direction horizontal to the light emitting surface. It may be classified into a lateral type (hereinafter, referred to as a “lateral light emitting device”) including first and second electrodes disposed side by side.

Among them, the lateral light emitting device may include a first electrode formed on an exposed n-type semiconductor layer by removing a portion of an ohmic contact layer, a p-type semiconductor layer, and an active layer, and a second electrode formed on the ohmic contact layer. Include.

That is, in the lateral light emitting device, the first electrode may be formed only by removing at least some regions of the ohmic contact layer, the p-type semiconductor layer, and the active layer. Therefore, in order to increase the contact area between the first electrode and the n-type semiconductor layer, the exposed area of the n-type semiconductor layer should be increased, and for this purpose, the ohmic contact layer, the p-type semiconductor layer, and the active layer are removed more. Should be. At this time, as the ohmic contact layer, the p-type semiconductor layer, and the active layer are removed, the area where the recombination of holes and electrons occurs is reduced, so that the light efficiency (here, the "light efficiency" is the amount of light emitted from the device relative to the injected charge amount). Corresponding to the ratio) is reduced.

In addition, since the resistance is inversely proportional to the area, the smaller the contact area between the first electrode and the n-type semiconductor layer, the higher the contact resistance between the first electrode and the n-type semiconductor layer. For this reason, the amount of the charge injected through the first electrode is lost at the interface between the first electrode and the n-type semiconductor layer is high, there is a problem that leads to a decrease in the light efficiency.

The present invention reduces the contact resistance by increasing the contact area between the first semiconductor layer and the electrode, without increasing the removal area of the active layer, the second semiconductor layer, and the ohmic contact layer stacked on the first semiconductor layer. It is to provide a light emitting device and a method of manufacturing the same that can increase the.

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; An ohmic contact layer formed of a transparent conductive material on the second semiconductor layer; A first groove formed through at least a portion of each of the ohmic contact layer, the second semiconductor layer, and the active layer to expose a first region of the first semiconductor layer; A second groove formed through at least a portion of the first semiconductor layer connected to at least a portion of the lower surface of the first groove and exposing a second region of the first semiconductor layer; A first electrode formed at least in the second groove to be in contact with at least a second region of the first semiconductor layer; And a second electrode formed on another portion of the ohmic contact layer.

In addition, the present invention comprises the steps of sequentially stacking a first semiconductor layer, an active layer and a second semiconductor layer on a substrate, to form a photoelectric layer; Stacking a transparent conductive material on the second semiconductor layer to form an ohmic contact layer; Removing at least a portion of each of the ohmic contact layer, the second semiconductor layer, and the active layer to form a first groove exposing a first region of the first semiconductor layer; Removing at least a portion of the first semiconductor layer connected to at least a portion of the lower surface of the first groove to form a second groove exposing a second region of the first semiconductor layer; And forming a first electrode contacting at least a second region of the first semiconductor layer in at least the second groove, and a second electrode contacting at least a portion of the ohmic contact layer. to provide.

As described above, the light emitting device according to the present invention penetrates at least a portion of the ohmic contact layer, the second semiconductor layer, and the active layer to expose the first region of the first semiconductor layer and the lower surface of the first groove. A first groove formed through and in contact with a second region of the first semiconductor layer in at least a second groove and at least a second groove that penetrates at least a portion of the first semiconductor layer subsequent to the at least a portion; An electrode.

As described above, according to the present invention, the first electrode is not formed flat on the first region of the first semiconductor layer at the bottom surface of the first groove, but is formed at least on the first groove of the first semiconductor layer along at least the second groove. In contact with two areas, it is formed three-dimensionally.

Accordingly, the contact area between the first semiconductor layer and the first electrode can be increased without increasing the width of the removal region of the ohmic contact layer, the second semiconductor layer, and the active layer, that is, the first groove. As a result, a decrease in light efficiency due to an increase in the removal region of the active layer can be prevented.

In addition, by increasing the contact area between the first semiconductor layer and the first electrode to reduce the contact resistance, the amount of charge dissipated at the interface between the first semiconductor layer and the first electrode can be reduced, resulting in a current injection efficiency. Can improve.

In addition, as the charge transfer path between the first electrode and the active layer is not in the plane to the plane but in the side to the plane, the amount of charge lost in the path between the first electrode and the active layer can be reduced. .

As the amount of charge lost is reduced, the light efficiency may be improved.

1 is a cross-sectional view of a light emitting device according to an embodiment of the present invention.
FIG. 2 is a cross-sectional perspective view of portion A of FIG. 1.
3 is a plan view of a light emitting device according to an exemplary embodiment of the present invention.
4 is a cross-sectional view illustrating II-II ′ of FIG. 3.
5A to 5C are cross-sectional views illustrating other examples of the portion A of FIG. 1.
6A to 6D are cross-sectional views illustrating still other examples of the portion A of FIG. 1.
7 is a flowchart illustrating a method of manufacturing a light emitting device according to an embodiment of the present invention.
8A to 8E are process charts showing the manufacturing method of the light emitting device shown in FIG.
9A and 9B are perspective views illustrating the first electrode forming region of FIG. 3 in detail.
10A and 10B are another perspective view illustrating the first electrode forming region of FIG. 3 in detail.

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 to 4, 5A to 5C, and 6A to 6D.

1 is a cross-sectional view of a light emitting device according to an embodiment of the present invention. 2 is a cross-sectional perspective view showing a portion A of FIG. 1, FIG. 3 is a plan view of a light emitting device according to an exemplary embodiment of the present invention, and FIG. 4 is a cross-sectional view illustrating II-II 'of FIG. 5A to 5C are cross-sectional views illustrating other examples of the portion A of FIG. 1, and FIGS. 6A to 6D are cross-sectional views illustrating still another examples of the portion A of FIG. 1. For reference, FIG. 1 is a cross-sectional view illustrating II ′ of FIG. 3.

As shown in FIG. 1, the light emitting device 100 according to the exemplary embodiment of the present invention includes a substrate 110, a buffer layer 120 formed on the substrate 110, and an undoped semiconductor layer stacked on the buffer layer 120. The photoelectric layer 140 and the second semiconductor layer 130 including the first semiconductor layer 141, the active layer 142, and the second semiconductor layer 143 sequentially stacked on the undoped semiconductor layer 130. An ohmic contact layer 150 formed of a transparent conductive material on the 143 is included. The first groove 160 penetrates at least a portion of the ohmic contact layer 150, the second semiconductor layer 143, and the active layer 142 to expose the first region of the first semiconductor layer 141. At least one second groove 170 penetrating at least a portion of the first semiconductor layer 141 connected to at least a portion of the lower surface of the first groove to expose the second region of the first semiconductor layer, and at least the second groove The first electrode 181 formed in contact with at least the second region of the first semiconductor layer and the second electrode 182 formed on another portion of the ohmic contact layer 150.

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 120 is a buffer layer for reducing crystal defects of the photoelectric layer 130 generated due to the lattice constant and thermal expansion coefficient difference between the substrate 110 and the photoelectric layer 130. That is, when the substrate 110 and the photoelectric layer 130 are not selected as the same material, the buffer layer 120 may have a lattice constant and a thermal expansion coefficient of the semiconductor material forming the photoelectric layer 130. Since they do not coincide with each other, it is to minimize the occurrence of crystal defects in the semiconductor material grown on the substrate 110. Thus, when the substrate 110 is selected as the same material as the photoelectric layer 140, the substrate 110 may not include the buffer layer 120. The buffer layer 120 may be formed of thinly stacked SiOx or SiNx, or a low temperature grown semiconductor material.

The undoped semiconductor layer 130 is formed by stacking a semiconductor material that is not doped with impurities on the buffer layer 120.

The first semiconductor layer 141 is formed by stacking an n-type semiconductor doped with n-type impurities to increase electron mobility on the undoped semiconductor layer 130. In this case, the n-type impurity may be Si.

The active layer 142 is formed by stacking a semiconductor having a quantum well structure on the first semiconductor layer 141. In the active layer 142, electrons and holes injected through the first electrode 181 and the second electrode 182 meet and recombine to generate excitons, and the excitation energy generated as the excitons fall into the atmospheric state at this time Light is generated from.

For example, when the semiconductor material forming the photoelectric layer 140 is gallium nitride (GaN) -based, the active layer 142 may include a barrier layer of In _x (Al _y Ga _(1-y) ) N and In _x (Al _y). It may be formed as a single quantum well structure or multiple quantum well structure (MQW) consisting of a well layer of Ga _(1-y) ) N. 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.

The second semiconductor layer 143 is formed by stacking a p-type semiconductor doped with a p-type impurity to increase hole mobility on the active layer 142. In this case, the p-type impurity may be Mg.

Meanwhile, the undoped semiconductor layer 130 and the photoelectric layer 140 may be formed by growing a semiconductor material using a metal organic chemical vapor deposition (MOCVD) method.

The ohmic contact layer 150 is used to diffuse the holes injected through the second electrode 182 to the second semiconductor layer 143 as wide as possible. The ohmic contact layer 150 is formed of a transparent conductive material on the second semiconductor layer 143. . In this case, the transparent conductive material forming the ohmic contact layer 150 may be any one of metal oxides of SnO ₂ , ZnO, In ₂ O _3, and TiO ₂ and F, Sn, Al, Fe, Ga, and Nb. At least one may be selected as the doped material.

The first groove 160 is formed to penetrate a portion of each of the ohmic contact layer 150, the second semiconductor layer 143, and the active layer 142 to expose the first region of the first semiconductor layer 141. In this case, when the first groove 160 is formed to contact the upper surface of the first semiconductor layer 141, the first region of the first semiconductor layer 141 is exposed to the outside by the lower surface of the first groove 160. It means the aspects that become. Alternatively, when the first groove 160 is formed to further pass through a portion of the first semiconductor layer 141, the first region of the first semiconductor layer 141 may be formed with at least a portion of the side surface of the first groove 160. Means are surfaces exposed to the outside by the lower surface of the first groove 160.

The second groove 170 is formed to penetrate at least a portion of the first semiconductor layer 141 connected to at least a portion of the lower surface of the first groove 160 to expose the second region of the first semiconductor layer 141. . In this case, when the second groove 170 is formed to penetrate only the first semiconductor layer 141, the second region of the first semiconductor layer 141 is exposed to the outside by the side surfaces and the bottom surface of the second groove 170. It means the aspects that become. Alternatively, when the second groove 170 is formed to penetrate a portion of each of the first semiconductor layer 141 and the undoped semiconductor layer 130, the second region of the first semiconductor layer 141 may be the second groove 170. The first electrode 181 is an undoped semiconductor layer 130 exposed by the second region and the second groove 170 of the first semiconductor layer 141. It is formed in contact with a portion of the region.

The first groove 160 and the second groove 170 will be described in more detail below.

The first electrode 181 is formed in contact with the second region of the first semiconductor layer 141 at least in the second groove 170. Alternatively, the first electrode 181 may be formed not only on the second region of the first semiconductor layer 141 by the second groove 170, but also on the side surface or the bottom surface of the first groove 160. It may be formed in contact with more than a portion of the first region of. Alternatively, when the second groove 170 is formed to penetrate a portion of each of the first semiconductor layer 141 and the undoped semiconductor layer 130, the first electrode 181 is exposed by the second groove 170. It may be formed in contact with a portion of the undoped semiconductor layer 130.

That is, as shown in FIG. 2, the first electrode 181 is formed on a lower surface of the first groove 160 to be two-dimensionally flat in contact with the first region of the first semiconductor layer 141. Unlike the related art, at least a second region of the first semiconductor layer 141 is formed in three dimensions along at least the second groove 170.

Accordingly, regardless of the width of the first groove 160, the contact area between the first semiconductor layer 141 and the first electrode 181 increases, and inversely, the contact resistance at the interface between the two decreases. do. As described above, due to the decrease in the contact resistance, the amount of the charge injected through the first electrode 181 at the interface between the first semiconductor layer 141 and the first electrode 181 may be reduced. From such improvement of the current injection efficiency, it can be expected that the light efficiency will be improved.

In addition, the charge injected through the side surface of the first electrode 181 may be more widely diffused in the first semiconductor layer 141. In addition, unlike the conventional case in which the movement path of the charge is generated only from the first electrode in the plane to the active layer, the charge path may be generated in various forms between each of the side and bottom surfaces of the first electrode and the active layer. Since the charge dissipation rate can be reduced, it can be expected that the light efficiency is improved.

Referring back to FIG. 1, the second electrode 182 is formed on another portion of the ohmic contact layer 150. In this case, the second electrode 182 may be electrically connected to the second semiconductor layer 143 through the ohmic contact layer 150, or may be formed through a contact hole (not shown) passing through the ohmic contact layer 150. 2 may be directly connected to the semiconductor layer 143.

As shown in FIG. 3, the first electrode 181 is formed in a plurality of branches extending from the first electrode pad 181p, and the second electrode 182 is formed on the second electrode pad 182p. It is formed in the form of a plurality of extended branches. The first and second electrodes 181 and 182 are alternately disposed on a plane parallel to the stacked surface of the photoelectric layer 130, thereby reducing a horizontal path between the two.

In addition, as illustrated in FIG. 4, the second electrode pad 182p may be formed to directly contact the second semiconductor layer 143 through a contact hole 182h penetrating the ohmic contact layer 150.

The first and second electrodes 181 and 182 may be formed of the same or different conductive materials, in particular, a stack structure including any one metal or two or more of Ni, Au, Pt, Ti, Al, and Cr. Or alloys. In this case, the first and second electrode pads 181p and 182p are formed as part of the first and second electrodes 181 and 182, respectively, and are provided as bonding portions to be connected to the outside.

Meanwhile, the depth of the first groove 160 is such that the ohmic contact layer 150 and the second semiconductor layer may expose the first region of the first semiconductor layer 141 on the lower surface of the first groove 160. The depth of each of the 143 and the active layer 142 is equal to or greater than a first depth, and the first and second regions of the first semiconductor layer 141 may be exposed on the bottom and side surfaces of the first groove 160. The first depth and the depth of the first semiconductor layer 141 are determined to be equal to or less than the second depth.

The third depth, which is the sum of the depths of each of the first groove 160 and the second groove 170, is formed on the lower and side surfaces of the second groove 170 to form the second region of the second semiconductor layer 141. In order to be exposed, the ohmic contact layer 150 and the photoelectric layer may be larger than the first depth and further expose a portion of the undoped semiconductor layer 130 at the bottom and side surfaces of the second groove 170. 140) and the depth of each of the undoped semiconductor layers 130 is determined to be less than the fourth depth.

In addition, the first groove 160 has a cross section of any one of an inverted trapezoid, a trapezoid and a rectangle, and the second groove 170 has an inverted trapezoid and a trapezoid. , Rectangular and inverted triangular. In this case, the first groove 160 and the second groove 170 may have the same or different cross sections.

In addition, the width of the upper surface of the second groove 170 is determined to be equal to or less than the width of the lower surface of the first groove 160. That is, the upper surface of the second groove 170 may have the same width as the lower surface of the first groove 160, and may have a shape directly connected to the first groove 160, or the lower surface of the first groove 160. Since the width is smaller than the surface, a portion of both sides of the lower surface of the first groove 160 may be maintained as it is.

For example, as shown in FIGS. 1 and 2, the first groove 160 has a cross section of an inverted trapezoid and a portion of the first semiconductor layer 141 that is greater than the first depth and less than the second depth. The second groove 170 is formed by exposing the upper surface having a width smaller than the lower surface of the first groove 160, the cross section of the inverted trapezoid, and the depths of the ohmic contact layer 150 and the photoelectric layer 140, respectively. It may be formed to expose only the first semiconductor layer 141 to a depth less than the fifth depth.

Alternatively, as shown in FIG. 5A, the first groove 160a may be formed to expose the upper portion of the first semiconductor layer 141 at a lower surface thereof to a first depth, as shown in FIG. 5B. The first groove 160b may have a rectangular cross section, and as shown in FIG. 5C, the first groove 160c may have a trapezoidal cross section.

In addition, as shown in FIG. 6A, the second groove 170a may be formed to expose the undoped semiconductor layer 130 at its lower surface to a depth that is greater than the fifth depth and less than the fourth depth, and in FIG. 6B. As shown, the second groove 170b has a cross section of an inverted trapezoid different from the first groove 160, and an upper surface having the same width as the lower surface of the first groove 160, so that the first groove 160 has the same shape. 6C, the second groove 170c may have an inverted triangular cross section.

In addition, as illustrated in FIG. 6D, the second groove 170d may be formed in the form of being connected to the first groove 160 as if the first groove 160 and the second groove 170 are integrated.

Next, a method of manufacturing a light emitting device according to an embodiment of the present invention will be described with reference to FIGS. 7 and 8A to 8E.

7 is a flowchart illustrating a method of manufacturing a light emitting device according to an exemplary embodiment of the present invention, and FIGS. 8A to 8E are flowcharts illustrating a method of manufacturing the light emitting device shown in FIG. 7.

As shown in FIG. 7, in the method of manufacturing the light emitting device according to the embodiment of the present invention, sequentially depositing a first semiconductor layer, an active layer, and a second semiconductor layer on a substrate to form a photoelectric layer (S100). Stacking a transparent conductive material on the second semiconductor layer to form an ohmic contact layer (S110), and removing a part of each of the ohmic contact layer, the second semiconductor layer, and the active layer, and thereby forming a first region of the first semiconductor layer. Forming a first groove exposing the second groove and removing at least a portion of the first semiconductor layer that is connected to at least a portion of the lower surface of the first groove to expose the second region of the first semiconductor layer. Forming step (S130). And forming a first electrode in contact with at least a second region of the first semiconductor layer and a second electrode in contact with at least a portion of the ohmic contact layer in at least a second groove (S140).

As shown in FIG. 8A, in the forming of the photoelectric layer 140 (S100), the first semiconductor layer 141 is formed of an n-type semiconductor doped with n-type impurities on the substrate 110. Forming an active layer 142 with a nitride semiconductor having a quantum well structure on the first semiconductor layer 141 and a second semiconductor layer 143 having a p-type semiconductor doped with p-type impurities on the active layer 142. Forming a step).

In addition, when the substrate 110 and the photoelectric layer 130 are heterogeneous materials, before the forming of the photoelectric layer 130 (S100), the forming of the buffer layer 120 and the impurities on the buffer layer 120 may be performed. The method may further include forming an undoped semiconductor layer 130 by growing an undoped semiconductor material. Here, the forming of the buffer layer 120 may be performed in an atmosphere including low-temperature heat for growing the semiconductor material mainly in a direction parallel to the growth surface.

The forming of the undoped semiconductor layer 130, the forming of the first semiconductor layer 141, the forming of the active layer 142, and the forming of the second semiconductor layer 143 each include a semiconductor. It is carried out in an atmosphere containing high temperature heat which mainly causes the material to grow along the direction perpendicular to the growth plane. For example, when the step (S100) of forming the photoelectric layer 140 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 shown in FIG. 8B, an ohmic contact layer 150 is formed by stacking a transparent conductive material on the second semiconductor layer 143 (S110).

As shown in FIG. 8C, a portion of the ohmic contact layer 150, the second semiconductor layer 143, and the active layer 142 may be removed to expose the first region of the first semiconductor layer 141. To form 160 (S120).

As shown in FIG. 8D, at least a portion of the first semiconductor layer 141 is removed after at least a portion of the lower surface of the first groove 160 to remove the second region of the first semiconductor layer 141. Forming a second groove 170 to expose the (S130).

Subsequently, as shown in FIG. 8E, a metal layer selected from a metal or any of a laminated structure or alloy including at least one of Ni, Au, Pt, Ti, Al, and Cr is laminated, and patterned to form at least a second layer. The first electrode 181 in contact with the second region of the first semiconductor layer 141 and the second electrode 182 in contact with the other portion of the ohmic contact layer 150 are formed (S140).

In this case, the first electrode 181 may have a three-dimensional shape, and may be formed to contact the second region of the first semiconductor layer 141 in the second groove 170 or the first groove 160 in the first groove 160. A portion of the first region of the semiconductor layer 141 is formed to contact the second region.

Next, a light emitting device according to another exemplary embodiment of the present invention will be described with reference to FIGS. 9A and 9B and FIGS. 10A and 10B, respectively.

9A and 9B are perspective views illustrating the first electrode forming region of FIG. 3 in detail. 10A and 10B are another perspective view illustrating the first electrode forming region of FIG. 3 in detail.

The light emitting device of FIGS. 9A to 10B will be described with reference to the same components (here, the same components shown in FIGS. 1 to 8E are denoted by the same reference numerals in the following description) of the above-described embodiment. The first semiconductor layer sequentially stacked on the substrate 110, the buffer layer 120 formed on the substrate 110, the undoped semiconductor layer 130 stacked on the buffer layer 120, and the undoped semiconductor layer 130. 141, an photoelectric layer 140 including an active layer 142, and a second semiconductor layer 143, and an ohmic contact layer 150 formed of a transparent conductive material on the second semiconductor layer 143. The first groove 160 penetrates at least a portion of the ohmic contact layer 150, the second semiconductor layer 143, and the active layer 142 to expose the first region of the first semiconductor layer 141. A plurality of second grooves 170 penetrating at least a portion of the first semiconductor layer 141 connected to at least a portion of the lower surface of the first groove to expose the second region of the first semiconductor layer, and a complex second groove The first electrode 181 formed on and in contact with the second region of the first semiconductor layer and the second electrode 182 formed on another portion of the ohmic contact layer 150 are included.

As described above, the same components shown in FIGS. 1 to 8E will be described with the same reference numerals in the following description. Referring to FIG. 9A, each of the first grooves 160 may include an ohmic contact layer 150, A portion of each of the second semiconductor layer 143 and the active layer 142 may be formed to expose the first region of the first semiconductor layer 141. In this case, when the first groove 160 is formed to contact the upper surface of the first semiconductor layer 141, the first region of the first semiconductor layer 141 is exposed to the outside by the lower surface of the first groove 160. It means the aspects that become. Alternatively, when the first groove 160 is formed to further pass through a portion of the first semiconductor layer 141, the first region of the first semiconductor layer 141 may be formed with at least a portion of the side surface of the first groove 160. Means are surfaces exposed to the outside by the lower surface of the first groove 160.

The plurality of second grooves 170 may be formed to penetrate at least a portion of the first semiconductor layer 141 which is connected to at least a portion of the lower surface of the first groove 160, and thus may be formed of the first semiconductor layer 141. 2 Expose area. In this case, when each of the plurality of second grooves 170 is formed to penetrate only the first semiconductor layer 141, the second region of the first semiconductor layer 141 may have side surfaces and bottom surfaces of the plurality of second grooves 170. It means the surfaces exposed by the outside. Alternatively, when the second groove 170 is formed to penetrate a portion of each of the first semiconductor layer 141 and the undoped semiconductor layer 130, the second region of the first semiconductor layer 141 may be a plurality of second grooves. (170) refers to surfaces exposed to the outside by side surfaces, and the first electrode 181 is an undoped semiconductor exposed by the second region of the first semiconductor layer 141 and the plurality of second grooves 170. It is formed in contact with a portion of the layer 130.

Accordingly, as shown in FIG. 9B, the first electrode 181 is formed in contact with the second region of the first semiconductor layer 141 in the plurality of second grooves 170. Alternatively, the first electrode 181 may be formed not only on the second region of the first semiconductor layer 141 by the plurality of second grooves 170, but also on the side surface or the bottom surface of the first groove 160. It may be formed in contact with more than a portion of the first region of 141. In addition, when the first electrode 181 is formed such that the plurality of second grooves 170 penetrate a part of each of the first semiconductor layer 141 and the undoped semiconductor layer 130, the first electrode 181 may be formed in a plurality of manners. It may be formed in contact with a portion of the undoped semiconductor layer 130 exposed by the second groove 170. That is, the first electrode 181 may be formed in three dimensions in contact with at least a second region of the first semiconductor layer 141 along the plurality of second grooves 170.

Accordingly, regardless of the width of the first groove 160, the contact area between the first semiconductor layer 141 and the first electrode 181 increases, and inversely, the contact resistance at the interface between the two decreases. do. As described above, due to the decrease in the contact resistance, the amount of the charge injected through the first electrode 181 at the interface between the first semiconductor layer 141 and the first electrode 181 may be reduced. From such improvement of the current injection efficiency, it can be expected that the light efficiency will be improved.

In addition, the charge injected through the side surface of the first electrode 181 may be more widely diffused in the first semiconductor layer 141. In addition, it can be generated in various forms between each of the side surface and the lower surface of the first electrode and the active layer, the charge loss rate due to the movement path can be reduced, it can be expected that the light efficiency is improved.

In addition, the first groove 160 has a cross section of any one of an inverted trapezoid, a trapezoid, and a rectangle, and the plurality of second grooves 170 formed by the plurality of second grooves 170 are inverted based on a surface perpendicular to the stacked surface of the photoelectric layer 140. It has a cross section of any of trapezoid, trapezoid, rectangle and inverted triangle. In this case, the first groove 160 and the second groove 170 may have the same or different cross sections. To this end, the width of the upper surface of the second groove 170 is determined to be less than half the width of the lower surface of the first groove 160 so that a plurality of second grooves 170 are formed.

In particular, as shown in FIGS. 10A and 10B, respectively, the upper surface of the second groove 170 is less than half the width of the lower surface of the first groove 160, and the length of one side is a long rectangular shape. It may be configured to be made of a plurality. In this case, the plurality of second grooves 170 may be configured in the form of a plurality of slits such that both side portions of the lower surfaces of the first grooves 160 may be maintained up to the side of each of the second grooves 170.

As described above, the light emitting device according to the exemplary embodiment of the present invention may include the first semiconductor layer 141 through the plurality of second grooves 170 or through the first grooves 160 and the second grooves 170. By including the first electrode 181 formed to be in three-dimensional contact, it is possible to improve the light efficiency.

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: light emitting device 110: substrate
120: buffer layer 130: undoped semiconductor layer
140: photoelectric layer 141: first semiconductor layer
142: active layer 143: second semiconductor layer
150: ohmic contact layer 160: first groove
170: second grooves 181, 182: first and second electrodes
181p and 182p: first and second electrode pads
182h: contact hole

Claims (17)

Board;
A photovoltaic layer including a first semiconductor layer, an active layer, and a second semiconductor layer sequentially stacked on the substrate;
An ohmic contact layer formed of a transparent conductive material on the second semiconductor layer;
A first groove formed through at least a portion of each of the ohmic contact layer, the second semiconductor layer, and the active layer to expose a first region of the first semiconductor layer;
At least one second groove formed through at least a portion of the first semiconductor layer connected to at least a portion of the lower surface of the first groove and exposing a second region of the first semiconductor layer;
A first electrode formed in contact with at least a second region of the first semiconductor layer in the at least one second groove; And
A light emitting device comprising a second electrode formed on another portion of the ohmic contact layer. The method of claim 1,
The first electrode and the second electrode are a plurality of branch forms extending from the first electrode pad and the second electrode pad, respectively, and are disposed alternately in a plane parallel to the photoelectric layer. The method of claim 1,
The at least one second groove upper surface has a width smaller than the lower surface of the first groove or the same width as the lower surface of the first groove. The method of claim 1,
The first electrode is formed in the first groove, the light emitting element further contacted with at least a portion of the first region of the first semiconductor layer. The method of claim 1,
The semiconductor device further comprises an undoped semiconductor layer made of a semiconductor material which is not doped with impurities between the substrate and the photoelectric layer.
The at least one second groove further penetrates at least a portion of the undoped semiconductor layer to expose a portion of the undoped semiconductor layer,
The first electrode is formed to be in contact with the partial region of the undoped semiconductor layer. The method of claim 1,
The first groove has a cross section of any one of an inverted trapezoid, a trapezoid, and a rectangle, based on a surface perpendicular to the stacked surface of the photoelectric layer.
The at least one second groove has a cross section of any one of an inverted trapezoid, a trapezoid, a rectangle, and an inverted triangle, based on a plane perpendicular to the stacking surface of the photoelectric layer,
The first groove and the second groove light emitting device having the same or different cross section. The method according to claim 6,
When the cross section of the at least one second groove is any one of an inverted trapezoid, trapezoid and rectangle having a flat lower surface,
And the first electrode is formed in three-dimensional contact with the second region of the first semiconductor layer along side surfaces and bottom surfaces of the at least one second groove. The method of claim 1,
The depth of the first groove is equal to or greater than the first depth of the sum of the depths of the ohmic contact layer, the second semiconductor layer, and the active layer, and equal to or less than the second depth of the sum of the depths of the first depth and the second semiconductor layer.
The third depth, which is the sum of the depths of the first groove and the at least one second groove, is greater than the first depth and less than a fourth depth that is the sum of the depths of each of the ohmic contact layer, the photoelectric layer, and the undoped semiconductor layer. Light emitting element. The method of claim 1,
The first groove and the at least one second groove is an integral shape of the light emitting device. 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. Sequentially stacking a first semiconductor layer, an active layer, and a second semiconductor layer on a substrate to form a photoelectric layer;
Stacking a transparent conductive material on the second semiconductor layer to form an ohmic contact layer;
Removing at least a portion of each of the ohmic contact layer, the second semiconductor layer, and the active layer to form a first groove exposing a first region of the first semiconductor layer;
Removing at least a portion of the first semiconductor layer connected to at least a portion of the lower surface of the first groove to form at least one second groove exposing a second region of the first semiconductor layer; And
Forming a first electrode in contact with at least a second region of the first semiconductor layer and a second electrode in contact with at least a portion of the ohmic contact layer in the at least one second groove; . The method of claim 11,
In the forming of the first and second electrodes,
The first electrode and the second electrode are a plurality of branch forms extending from the first electrode pad and the second electrode pad, respectively, and a method of manufacturing a light emitting device that is alternately arranged on a plane parallel to the stacking surface of the photoelectric layer. . The method of claim 11,
In the forming of the first and second electrodes,
And the first electrode is disposed to be in contact with at least a portion of the first region of the first semiconductor layer in the first groove. The method of claim 11,
Prior to forming the photoelectric layer, further comprising forming an undoped semiconductor layer by stacking a semiconductor material which is not doped with impurities on the substrate,
In the forming of the second groove, at least a portion of the undoped semiconductor layer is further removed to form at least one second groove further exposing a portion of the undoped semiconductor layer.
In the forming of the first and second electrodes, the first electrode is disposed to be in contact with a portion of the undoped semiconductor layer further. The method of claim 11,
In the forming of the first groove, the first groove has a cross section of any one of an inverted trapezoid, a trapezoid, and a rectangle, based on a surface perpendicular to the stacking surface of the photoelectric layer.
In the forming of the at least one second groove, the at least one second groove has a cross section of any one of an inverted trapezoid, a trapezoid, a rectangle, and an inverted triangle with respect to a surface perpendicular to the stacking surface of the photoelectric layer. Has,
The first groove and the second groove is a method of manufacturing a light emitting device having the same or different cross section. The method of claim 11,
In the forming of the first groove, a depth of the first groove is equal to or greater than a first depth of a sum of depths of the ohmic contact layer, the second semiconductor layer, and the active layer, respectively, the first depth and the second semiconductor layer. Is less than the second depth sum of
In the forming of the at least one second groove, a third depth of the sum of the depths of each of the first groove and the at least one second groove is greater than the first depth, and each of the ohmic contact layer and the photoelectric layer. The method of manufacturing a light emitting device having a depth of less than a fourth depth. The method of claim 11,
The forming of the first groove and the forming of the at least one second groove are simultaneously performed.

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