KR20170095675A - Light emitting device - Google Patents

Abstract

According to an embodiment of the present invention, provided is a light-emitting device capable of improving an optical output by minimizing a decrease in a light-emitting area. The light-emitting device comprises: a substrate; a light-emitting structure disposed on the substrate, including a first semiconductor layer, an active layer, and a second semiconductor layer, and having four side surfaces, wherein at least one of the four side surfaces is mesa-etched to expose the top surface of the first semiconductor layer; one or more grooves concavely formed in an inward direction of the light-emitting structure on at least one side surface of the light-emitting structure, including a bottom surface for exposing the top surface of the first semiconductor layer, and including a side surface for exposing the side surfaces of the first semiconductor layer, the active layer, and the second semiconductor layer; a first electrode including a first electrode pad and a first finger extended from the first electrode pad, electrically coming in contact with the first semiconductor layer, and directly coming in contact with the first semiconductor layer in which the first finger is exposed from the bottom surface of the groove; and a second electrode electrically coming in contact with the second semiconductor layer.

Description

[0001] LIGHT EMITTING DEVICE [0002]

An embodiment of the present invention relates to a light emitting device having improved light emitting output.

A light emitting diode (LED) is one of light emitting devices that emits light when current is applied. Light emitting diodes are capable of emitting light with high efficiency at low voltage, thus saving energy. In recent years, the problem of luminance of a light emitting diode has been greatly improved, and it has been applied to various devices such as a backlight unit of a liquid crystal display device, a display board, a display device, and a home appliance.

The light emitting diode may include a light emitting structure composed of a first semiconductor layer, an active layer and a second semiconductor layer, a first electrode electrically connected to the first semiconductor layer, and a second electrode electrically connected to the second semiconductor layer. At this time, the first electrode is electrically connected to the exposed first semiconductor layer by selectively removing the light emitting structure.

However, when the light emitting structure is selectively removed for electrical connection between the first electrode and the first semiconductor layer, there arises a problem that the area of the active layer is reduced and the light emitting region of the light emitting device is reduced. That is, as the area of the active layer decreases, the non-emission region of the light emitting device increases and the light output decreases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a light emitting device capable of minimizing a non-emission region by electrically connecting a first semiconductor layer and a first electrode through at least one groove formed in a side surface of a mesa-etched light emitting structure.

A light emitting device of an embodiment of the present invention includes a substrate; A light emitting structure disposed on the substrate, the light emitting structure including a first semiconductor layer, an active layer, and a second semiconductor layer, wherein at least one side of the four sides is mesa-etched to expose an upper surface of the first semiconductor layer; A bottom surface that is recessed inward from the at least one side of the light emitting structure and exposes an upper surface of the first semiconductor layer and a side surface of the first semiconductor layer, One or more grooves including exposed sides; The first semiconductor layer including a first electrode pad and a first finger extending from the first electrode pad, the first finger being electrically connected to the first semiconductor layer, A first electrode directly connected; And a second electrode electrically connected to the second semiconductor layer.

In addition, the light emitting device of another embodiment of the present invention includes a substrate; A light emitting structure disposed on the substrate, the light emitting structure including a first semiconductor layer, an active layer, and a second semiconductor layer, wherein at least one side of the four sides is mesa-etched to expose an upper surface of the first semiconductor layer; A bottom surface that is recessed inward from the at least one side of the light emitting structure and exposes an upper surface of the first semiconductor layer and a side surface of the first semiconductor layer, One or more grooves including exposed sides; The first semiconductor layer including a first electrode pad and a first finger extending from the first electrode pad, the first finger being electrically connected to the first semiconductor layer, A first electrode directly connected; And a second electrode electrically connected to the second semiconductor layer, wherein the first finger has a region overlapping an upper surface of the light emitting structure between the adjacent trenches and a width of a region connected to the first semiconductor layer Are different from each other.

The light emitting device of the embodiment of the present invention reduces the area of the active layer that is removed for electrical connection between the first electrode and the first semiconductor layer to minimize the non-emitting region of the light emitting device. Whereby the light output of the light emitting element is improved.

1A is a plan view of a light emitting device according to an embodiment of the present invention.
1B is a cross-sectional view taken along line I-I 'of FIG. 1A.
1C is a sectional view of II-II 'of FIG. 1A.
1D is a sectional view of III-III 'of FIG. 1A.
2 is an enlarged view of the area A in Fig. 1B.
3A and 3B are plan views in which the grooves have different lengths.
4 is a current diffusion photograph of Fig. 1A.
5A is a plan view of a light emitting device according to another embodiment of the present invention.
5B is a cross-sectional view taken along line I-I 'of FIG. 5A.
6A is a plan view of a light emitting device according to still another embodiment of the present invention.
6B is a cross-sectional view taken along line I-I 'of FIG. 6A.
FIGS. 7A and 7B are plan views showing the distance between the fingers of the first electrode and the second electrode of FIG. 1; FIG.
8A is a plan view showing another form of the first finger of the first electrode of the present invention.
8B is a plan view showing another embodiment of the electrode pad of the present invention.
9A is a plan view showing another connection structure of the first electrode and the first semiconductor layer of the present invention.
FIG. 9B is a cross-sectional view taken along line I-I 'of FIG. 9A.

The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated and described in the drawings. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Terms including ordinals, such as first, second, etc., may be used to describe various elements, but the elements are not limited to these terms. The terms may be used for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the second component may be referred to as a first component, and similarly, the first component may also be referred to as a second component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings, wherein like or corresponding elements are denoted by the same reference numerals, and redundant description thereof will be omitted.

Hereinafter, the light emitting device of the embodiment will be described in detail with reference to the accompanying drawings.

1A is a plan view of a light emitting device according to an embodiment of the present invention. FIG. 1B is a cross-sectional view taken along the line I-I 'of FIG. 1A, FIG. 1C is a cross-sectional view taken along line II-II' of FIG. 1A, and FIG. 1D is a cross-sectional view taken along line III-III 'of FIG. 1A.

1A to 1D, a light emitting device according to an embodiment of the present invention includes a substrate 100, a first semiconductor layer 110a, an active layer 110b, and a second semiconductor layer 110c disposed on the substrate 100, A bottom surface for exposing the first semiconductor layer 110a and a bottom surface for exposing the first semiconductor layer 110a and the active layer 110a are formed on the side surface of the light emitting structure 110, The first semiconductor layer 110a and the second semiconductor layer 110b are electrically connected to the first semiconductor layer 110a exposed at the bottom surface of the groove 120, And a second electrode 160 electrically connected to the electrode 150 and the second semiconductor layer 110c.

The first and second electrodes 150 and 160 are formed of first and second electrode pads 150a and 160a and first and second electrode pads 150a and 160a extending from the first and second electrode pads 150a and 160a, Although it has been described that the finger 150b and 160b are included, the number of the first and second fingers 150b and 160b is easily adjustable.

The substrate 100 may be formed of a material selected from sapphire (Al ₂ O ₃ ), SiC, GaAs, GaN, ZnO, Si, GaP, InP and Ge. The thickness of the substrate 100 may be 100 탆 to 270 탆, but is not limited thereto. Although not shown, a concavo-convex pattern may be further formed on the surface of the substrate 100 to improve light emission characteristics by dispersing light emitted from the light emitting structure 110.

A reflective layer 170 may be further disposed on the back surface of the substrate 100. The reflective layer 170 may be formed of a distributed Bragg reflector layer (DBR). In this case, the thickness of the reflective layer 170 may be 2 탆 to 7 탆, but is not limited thereto.

The DBR layer can be formed by alternately stacking two materials having different refractive indices. The DBR layer may be formed by repeating a first layer having a high refractive index and a second layer having a low refractive index. Both the first and second layers may be dielectric, and the high and low refractive indices of the first and second layers may be relative refractive indices. The light passing through the substrate 100 and traveling to the DBR layer among the light emitted from the light emitting structure 110 can not pass through the DBR layer due to the difference in refractive index between the first layer and the second layer, Can be reflected.

A buffer layer (not shown) may be further disposed between the first semiconductor layer 110a and the substrate 100. The buffer layer can mitigate the lattice mismatch between the first semiconductor layer 110a and the substrate 100. [ The buffer layer may be a combination of Group III and Group V elements or may include any one of GaN, InN, AlN, InGaN, AlGaN, InAlGaN, and AlInN. The buffer layer can be grown as a single crystal on the substrate 100, and the buffer layer grown with a single crystal can improve the crystallinity of the first semiconductor layer 110a.

The first semiconductor layer 110a may be formed of a compound semiconductor such as group III-V or II-VI, and the first semiconductor layer 110a may be doped with a first dopant. The first semiconductor layer 110a may be a semiconductor material having a composition formula of In _x Al _y Ga _{1 -x- y} N (0? X? 1, 0? _Y? 1, 0? _X + y? 1) GaN, AlGaN, InGaN, InAlGaN, and the like. The first dopant may be an n-type dopant such as Si, Ge, Sn, Se, or Te. When the first dopant is an n-type dopant, the first semiconductor layer 110a doped with the first dopant may be an n-type semiconductor layer.

The active layer 110b is a layer where electrons (or holes) injected through the first semiconductor layer 110a and holes (or electrons) injected through the second semiconductor layer 110c meet. The active layer 110b transitions to a low energy level as electrons and holes are recombined, and light having a wavelength corresponding thereto can be generated.

The active layer 110b may have any one of a single well structure, a multiple well structure, a single quantum well structure, a multi quantum well (MQW) structure, a quantum dot structure, or a quantum wire structure. But is not limited thereto.

The second semiconductor layer 110c is formed on the active layer 110b and may be formed of a compound semiconductor such as group III-V or II-VI group. The second semiconductor layer 110c may be doped with a second dopant . The second semiconductor layer 110c may be formed of a semiconductor material having a composition formula of In _x Al _y Ga _{1 -x- y} N (0? X? 1, 0? _Y? 1, 0? _X + , GaP, GaAs, GaAsP, and AlGaInP. When the second dopant is a p-type dopant such as Mg, Zn, Ca, Sr, or Ba, the second semiconductor layer 110c doped with the second dopant may be a p-type semiconductor layer.

In the light emitting structure 110, at least one side of the four sides may have a step. The step may occur through mesa etching to expose the top surface of the first semiconductor layer 110a. In the drawing, all four sides of the light emitting structure 110 have steps, and the upper surface of the first semiconductor layer 110a is exposed at the edges of the light emitting structure 110.

At least one side of the light emitting structure 100 in which the upper surface of the first semiconductor layer 110a is exposed may include at least one groove 120 formed concavely inward of the light emitting structure 110. In the drawing, five grooves 120 are formed on one side of the light emitting structure 110. The groove 120 includes a bottom surface for exposing the first semiconductor layer 110a and a side surface for exposing the sides of the first semiconductor layer 110a, the active layer 110b and the second semiconductor layer 110c. The groove 120 is for electrically connecting the first semiconductor layer 110a and the first electrode 150 exposed at the bottom surface.

The side surface of the groove 120 may have a curved surface as shown, but is not limited thereto. And, the intervals between the adjacent grooves 120 can be all the same or different from each other as shown, and are easily adjustable.

A current blocking layer (CBL) 130 may be disposed on the second semiconductor layer 110c to change a path of carriers injected from the second electrode 160. [ The current blocking layer 130 may prevent carriers from being concentrated in the region where the second semiconductor layer 110c and the second electrode 160 are connected and may disperse the carriers in the entire region of the second semiconductor layer 110c.

The current blocking layer 130 may be formed of a metal capable of forming a schottky contact with the second semiconductor layer 110c. For example, the current blocking layer 130 may be formed of at least one of titanium (Ti), zirconium (Zr), chromium (Cr), gold (Au), tungsten have. In addition, the current blocking layer 130 may be formed of a dielectric material such as SiOx, SiON, SixNy, or the like, but is not limited thereto.

The transparent electrode layer 135 may be further disposed on the second semiconductor layer 110c so as to cover the current blocking layer 130. [ The transparent electrode layer 135 may be electrically connected to the second electrode 160 to easily inject carriers into the second semiconductor layer 110c. The transparent electrode layer 135 may be formed of ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), AZO (Aluminum Zinc Oxide), AGZO (Indium Zinc Tin Oxide), IZO (Indium Aluminum Zinc Oxide) , Transparent conductive oxides such as IGZO (Indium Gallium Zinc Oxide), IGTO (Indium Gallium Tin Oxide), ATO (Antimony Tin Oxide), GZO (Gallium Zinc Oxide), IZON (IZO Nitride), ZnO, IrOx, RuOx and NiO Can be selected.

At this time, the transparent electrode layer 135 may be disposed so as to completely cover the upper surface and the side surface of the current blocking layer 130. Therefore, the thickness of the region corresponding to the side surface of the current blocking layer 130 in the thickness of the transparent electrode layer 135 is thin due to the step-coverage characteristic.

An insulating layer 140 may be disposed on the transparent electrode layer 135. The insulating layer 140 may expose a portion of the transparent electrode layer 135 such that the second electrode 160 and the transparent electrode layer 135 are electrically connected. It is preferable that a part of the region of the transparent electrode layer 135 exposed by the insulating layer 140 overlaps the current blocking layer 130. Accordingly, the second electrode 160 and the current blocking layer 130 may overlap with each other with the transparent electrode layer 135 interposed therebetween.

The insulating layer 140 is formed on the second semiconductor layer 110c and the active layer 110b exposed on the sides of the mesa etching and the groove 120 to prevent the first electrode 150 from being connected to the second semiconductor layer 110c. As shown in FIG. In particular, the insulating layer 140 may extend to a portion of the upper surface of the exposed first semiconductor layer 110a in consideration of the process margin.

When the distance d2 between the edge of the insulating layer 140 and the first finger 150b of the first electrode 150 is too close to the upper surface of the insulating layer 140, The contact area between the first finger 150b and the first semiconductor layer 110a may be reduced because the first finger 150b is formed. Accordingly, the edge of the insulating layer 140 and the first finger 150b must be sufficiently separated from each other, and the distance d2 between the edge of the insulating layer 140 and the first finger 150b is preferably 4 m or more Do. If the spacing d2 between the first fingers 150b is too large, the removal area of the active layer 110b increases. However, the spacing d2 is preferably 8 mu m or less, but is not limited thereto. That is, the distance d2 between the edge of the insulating layer 140 and the first finger 150b may be 4 占 퐉 or more and 8 占 퐉 or less.

The second electrode 160 may be connected to the transparent electrode layer 135 exposed by the insulating layer 140. The second electrode 160 may be formed of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, Hf, Do not.

The second electrode 160 may include one or more second fingers 160b extending from the second electrode pad 160a and the second electrode pad 160a. Respectively. The second electrode 160 may be completely overlapped with the current blocking layer 130 with the transparent electrode layer 135 interposed therebetween. For this purpose, the edge of the current blocking layer 130 is located outside the edge of the second electrode 160 As shown in FIG.

That is, since the width w1 of the current blocking layer 130 is wider than the width w2 of the second electrode 160 and the second electrode 160 is completely overlapped with the current blocking layer 130, 160 can be prevented from concentrating only on the second semiconductor layer 110c in the region where the carriers injected from the second electrode 160 are connected to the second electrode 160. [

If the width w1 of the current blocking layer 130 is too large, a part of the light emitted from the active layer 110b is absorbed by the current blocking layer 130 and light is lost. w1 and the width w2 of the second electrode 160 is greater than 0 and preferably less than or equal to 20 m.

The first electrode 150 may include a first electrode pad 150a and a first finger 150b extending from the first electrode pad 150a. The first electrode 150 may be formed of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, Hf, Ti, Cr, Cu, Do not.

The first electrode pad 150a may overlap the upper surface of the second semiconductor layer 110c with the insulating layer 140 interposed therebetween. Accordingly, when the light emitting device is wire-bonded, the wire bonding can be easily performed through the first electrode pad 150a disposed on the upper surface of the flat second semiconductor layer 110c.

The first finger 150b of the first electrode 150 may extend from the first electrode pad 150a so as to be electrically connected to the upper surface of the first semiconductor layer 110a exposed from the bottom surface of the groove 120 have. The width w3 of the first finger 150b may be narrower than the width of the first electrode pad 150a and narrower than the depth d1 of the groove 120. [

When the width w3 of the first finger 150b is narrow, the amount of light absorbed by the opaque first finger 150b is reduced, so that the light output is improved but the driving voltage is increased. Conversely, when the width w3 of the first finger 150b is too wide, the contact area between the first semiconductor layer 110a and the first finger 150b is widened to decrease the driving voltage, The amount of light absorbed by the light emitting layer increases. Therefore, the width w3 of the first finger 150b of the first electrode 150 may be 1 to 7 m, and more preferably the width w3 of the first finger 150b may be 3 to 7 Lt; / RTI > The width w3 of the first finger 150b is not limited thereto.

For example, when the size of the light emitting device is 1100 (占 퐉) x 300 (占 퐉) or less (the area is 330000 占 퐉 ² ), the width w3 of the first finger 150b of the first electrode 150 is 3 占 퐉 to 5 And the width w3 of the first finger 150b of the first electrode 150 may be 5 占 퐉 to 7 占 퐉 when the light emitting device exceeds 1100x300.

The distance d4 between the edge of the first finger 150b and the edge of the mesa-etched light-emitting structure 110 is preferably 4 탆 to 7 탆 in consideration of the process margin of the first electrode 150, But is not limited thereto.

If the overlapping distance d between the edge of the insulating layer 140 and the upper surface of the exposed first semiconductor layer 110a is too wide, the area of the first semiconductor layer 110a exposed from the bottom surface of the groove 120 . Accordingly, the connection area between the first electrode 150 and the first semiconductor layer 110a decreases, and the driving voltage increases. Also, in this case, the first finger 150b may be formed on the insulating layer 140. [

On the other hand, if the interval d is too narrow, the process margin of the insulating layer 140 is too small, and the second semiconductor layer 110c and the active layer 110b, which are exposed from the side surface of the groove 120, A problem that can not be wrapped may occur. Therefore, the distance d may be 4 탆 to 8 탆. However, if the process margin is not considered, the edge of the insulating layer 140 may extend only to the side surface of the trench 120, so that the interval d may be zero.

When the depth d1 of the groove 120 is too deep, the removal area of the active layer 110b as the light emitting region increases and when the depth d1 of the groove 120 is too shallow, the exposed area of the first semiconductor layer 110a The contact area between the first finger 150b and the first semiconductor layer 110a is also reduced and the driving voltage is increased.

Therefore, the width w3 of the first finger 150b, the distance d between the edge of the bottom surface of the groove 120 and the edge of the insulating layer 140 extending to the bottom surface of the groove 120, The distance d2 between the edge of the light emitting structure 140 and the first finger 150b and the distance d4 between the edge of the first finger 150b and the edge of the mesa- 120 may have a depth d1 of 15 mu m to 30 mu m, but is not limited thereto.

If the distance d3 between the first finger 150b and the edge of the light emitting structure 110 is too wide, the removal area of the light emitting region increases and the distance d3 is too narrow, The process margin of the etching can not be secured. For example, when the process margin of the mesa etching of the light emitting structure 110 is 10 mu m to 17.5 mu m, the interval d3 may be 21 mu m to 28.5 mu m. Particularly, in the case of minimizing the process margin of the mesa etching, the interval d3 may be 5 占 퐉 to 28.5 占 퐉.

The distance between the edge of the insulating layer 140 and the edge of the substrate 100 extending from the exposed portion of the substrate 100 to the upper surface of the first semiconductor layer 110a exposed by the mesa etching of the light emitting structure d6 may be 5 [mu] m to 20 [mu] m to secure a process margin of the mesa etching and a scribe process margin of the substrate 100 for separating the light emitting device.

Hereinafter, the connection between the first finger 150b of the first electrode 150 and the first semiconductor layer 110a will be described in detail.

2 is an enlarged view of the area A in Fig. 1B.

2, the first finger 150b of the first electrode 150 is electrically insulated from the active layer 110b and the second semiconductor layer 110c through the insulating layer 140, and at the same time, And may be electrically connected to the first semiconductor layer 110a exposed on the bottom surface.

As the length L2 of the groove 120 becomes longer, the removal area of the active layer 110b increases and as the length L2 of the groove 120 becomes shorter, the distance between the first semiconductor layer 110a and the first electrode 150 increases, The connection area of the first finger 150b of the first finger 150a can be narrowed. Therefore, the length L2 of the groove 120 may be 20 占 퐉 to 90 占 퐉 or more, but is not limited thereto. In particular, although the plurality of grooves 120 have the same length L2 in the drawing, the grooves 120 may have a different length L2.

3A and 3B are plan views in which the grooves have different lengths.

As shown in FIG. 3A, as the length of the groove 120 becomes longer as the distance from the first electrode pad 150a increases, or as the length of the groove 120 becomes longer from the first electrode pad 150a as shown in FIG. 3B, It can be shortened gradually. 3A, current can be easily diffused even in a region adjacent to the second electrode pad 160a, thereby improving light emission efficiency. In FIG. 3B, current injection is smooth in a region adjacent to the first electrode pad 150a. Although not shown, the length of the groove 120 may be irregular.

The contact length L1 between the first finger 150b of the first electrode 150 and the first semiconductor layer 110a is greater than the length L2 of the groove 120a and the distance L2 between the insulating layer 140 and the first semiconductor layer 110a. Can be determined according to the overlap length d of the upper surface of the upper surface 110a. That is, the length L1 of contact between the first finger 150b of the first electrode 150 and the first semiconductor layer 110a is in a range of 4 占 퐉 to 4 占 퐉 in consideration of the length L2 and the distance d of the groove 120 Lt; / RTI >

The light emitting device of the present invention may include a first semiconductor layer 110a and a first electrode 150 through at least one groove 120 formed on at least one side of the mesa-etched four sides of the light emitting structure 110, Point contact, so that the removal area of the active layer 110b can be minimized. In particular, since the first finger 150b in a region connected to the first semiconductor layer 110a exposed at the bottom surface of the groove 120 at the side of the mesa-etched light emitting structure 110 is exposed, the first electrode 150 Emitting region around the region where the first semiconductor layer 110a and the first semiconductor layer 110a are in contact with each other, thereby minimizing the non-emission region and preventing the light output from being lowered.

Particularly, when the size of the light emitting device of the embodiment of the present invention is 880 (占 퐉) x240 (占 퐉), the diameters of the first and second electrode pads 150a and 160a of the first and second electrodes 150 and 160 are 70 And in this case, the first and second electrode pads 150a and 160a may be 3.64% of the area of the light emitting device. The first and second fingers 150b and 160b of the first and second electrodes 150 and 160 may be 3.48% of the area of the light emitting device.

That is, when the first and second electrodes 150 and 160 are formed of an opaque material, light emitted from the active layer 110b is absorbed by the first and second electrodes 150 and 160, , And the first and second electrodes 150 and 160 do not exceed 4% of the total area of the light emitting device.

4 is a current diffusion photograph of Fig. 1A.

As shown in FIG. 4, in the light emitting device of the embodiment of the present invention, current is diffused to the front surface of the light emitting structure except for the groove 120 from which the active layer (110b in FIG. Therefore, the light emitting device of the embodiment of the present invention minimizes the non-light emitting area and increases the light emitting area, thereby preventing the light output from being lowered.

Hereinafter, a light emitting device according to another embodiment of the present invention will be described in detail.

FIG. 5A is a plan view of a light emitting device according to another embodiment of the present invention, and FIG. 5B is a cross-sectional view taken along line I-I 'of FIG. 5A.

5A and 5B, the light emitting device of another embodiment of the present invention is formed so that the insulating layer 140 completely exposes the transparent electrode layer 135. That is, the insulating layer 140 may be arranged to completely expose the transparent electrode layer 135, not to expose only a part of the transparent electrode layer 135 for connection with the second electrode 160.

6A is a plan view of a light emitting device according to still another embodiment of the present invention. 6B is a cross-sectional view taken along line I-I 'of FIG. 6A.

As shown in FIGS. 6A and 6B, in the light emitting device according to another embodiment of the present invention, the transparent electrode layer 135 may be disposed between the first electrode 150 and the second semiconductor layer 110c. In this case, the carriers injected through the first electrode 150 can be easily diffused.

That is, the formation position of the insulating layer 140 and the transparent electrode layer 135 can be easily controlled as in the other embodiments of the present invention.

Particularly, the light emission output of the light emitting device can be adjusted according to the distance d5 between the first and second fingers 150b and 160b of the first and second electrodes 150 and 160.

FIGS. 7A and 7B are plan views showing the distance between the fingers of the first electrode and the second electrode of FIG. 1; FIG.

Referring to FIGS. 7A and 7B, the light emitting device of FIG. 7A differs from the light emitting device of FIG. 7B in the interval d5 (d5) between the first and second fingers 150b and 160b of the first and second electrodes 150 and 160 The light emission output is lower than that of the light emitting device of 7b.

That is, as the distance d5 between the first and second fingers 150b and 160b of the first and second electrodes 150 and 160 is narrowed, the light emission output is increased. In this case, The current diffusion into the region B between the edges of the light emitting structure 110 may be reduced and the uniformity of light emission of the light emitting device may be reduced. For example, when the size of the light emitting device is 750 (占 퐉) x 220 (占 퐉), the distance d5 between the first and second fingers 150b and 160b of the first and second electrodes 150 and 160 is Mu] m to 110 [mu] m.

8A is a plan view showing another form of the first finger of the first electrode of the present invention.

8A, in order to increase the contact area between the first finger 150b of the first electrode 150 and the first semiconductor layer 110a to reduce the operating voltage, the light emitting structure 110 The width of the first finger 150b in the region overlapping the first semiconductor layer 110a may be different from the width of the first finger 150b in the region contacting the first semiconductor layer 110a exposed in the bottom surface of the groove 120 . In this case, the width of the first finger 150b is larger than the width of the region where the first semiconductor layer 110a is in contact with the second semiconductor layer 110c.

To this end, the first finger 150b may include a protrusion 150c in a region contacting the first semiconductor layer 110a exposed at the bottom surface of the groove 120. [ The width of the protrusion 150c should be smaller than the distance d3 between the first finger 150b and the edge of the substrate 100 in consideration of scribing of the substrate 100, (w4) may be less than 28.5 mu m.

 The shape of the protrusion 150c can be easily changed and the first finger 150b includes the protrusion 150c in each region corresponding to the groove 120. However, (Not shown). Further, the protrusion 150c may be formed at both edges of the first finger 150b, but is not limited thereto.

In this case, the contact area between the first finger 150b of the first electrode 150 and the first semiconductor layer 110a is widened, and the driving voltage of the light emitting device can be reduced.

8B is a plan view showing another embodiment of the electrode pad of the present invention.

As shown in FIG. 8B, the first and second electrode pads 150a and 160a of the present invention may be formed of a square having no curvature.

Particularly, when the size of the light emitting device of the embodiment of the present invention is 880 (占 퐉) x240 (占 퐉), the diameters of the first and second electrode pads 150a and 160a of the first and second electrodes 150 and 160 are 70 And in this case, the first and second electrode pads 150a and 160a may be 3.64% of the area of the light emitting device. The first and second fingers 150b and 160b of the first and second electrodes 150 and 160 may be 3.48% of the area of the light emitting device.

That is, when the first and second electrodes 150 and 160 are formed of an opaque material, light emitted from the active layer 110b is absorbed by the first and second electrodes 150 and 160, , And the first and second electrodes 150 and 160 do not exceed 4% of the total area of the light emitting device.

In the light emitting device of the present invention, the first electrode pad 150a and the first semiconductor layer 110a may be directly connected.

FIG. 9A is a plan view showing another connection structure of the first electrode and the first semiconductor layer of the present invention, and FIG. 9B is a cross-sectional view taken along line I-I 'of FIG. 9A.

9A and 9B, when the light emitting structure 110 is mesa-etched to expose the first semiconductor layer 110a, the active layer 110b is also formed in the region where the first electrode pad 150a is to be formed, And the second semiconductor layer 110c may be removed. The first electrode pad 150a is formed directly on the exposed first semiconductor layer 110a after the active layer 110b and the second semiconductor layer 110c are removed and the first electrode pad 150a and the second electrode layer 150b are formed. 1 semiconductor layer 110a may be directly connected. Accordingly, current injection from the first electrode pad 150a to the first semiconductor layer 110a is smooth, and the driving voltage can be reduced.

As described above, the light emitting device of the embodiment of the present invention includes the first electrode 150 and the first semiconductor layer 150 through one or more grooves 120 formed concavely inward of the light emitting structure 110 at the side surface of the light emitting structure 110. [ (110a) can be electrically connected. Thus, the removal area of the active (110b) layer can be reduced to minimize the reduction of the light emitting region.

The light emitting device of the embodiment of the present invention may further include an optical member such as a light guide plate, a prism sheet, and a diffusion sheet to function as a backlight unit. Further, the light emitting element of the embodiment can be further applied to a display device, a lighting device, and a pointing device.

At this time, the display device may include a bottom cover, a reflector, a light emitting module, a light guide plate, an optical sheet, a display panel, an image signal output circuit, and a color filter. The bottom cover, the reflector, the light emitting module, the light guide plate, and the optical sheet may form a backlight unit.

The reflector is disposed on the bottom cover, and the light emitting module emits light. The light guide plate is disposed in front of the reflection plate to guide light emitted from the light emitting element forward, and the optical sheet includes a prism sheet or the like and is disposed in front of the light guide plate. The display panel is disposed in front of the optical sheet, and the image signal output circuit supplies an image signal to the display panel, and the color filter is disposed in front of the display panel.

The lighting device may include a light source module including a substrate and a light emitting device of the embodiment, a heat dissipation unit that dissipates heat of the light source module, and a power supply unit that processes or converts an electric signal provided from the outside and provides the light source module . Further, the lighting device may include a lamp, a head lamp, or a street lamp or the like.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. It will be clear to those who have knowledge.

100: substrate 110: light emitting structure
110a: first semiconductor layer 110b: active layer
110c: second semiconductor layer 120:
130: current blocking layer 135: transparent electrode layer
140: insulating layer 150: first electrode
150a: first electrode pad 150b: first finger
150c: protrusion 160: second electrode
160a: second electrode pad 160b: second finger
170: reflective layer

Claims (20)

Board;
A light emitting structure disposed on the substrate, the light emitting structure including a first semiconductor layer, an active layer, and a second semiconductor layer, wherein at least one side of the four sides is mesa-etched to expose an upper surface of the first semiconductor layer;
A bottom surface that is recessed inward from the at least one side of the light emitting structure and exposes an upper surface of the first semiconductor layer and a side surface of the first semiconductor layer, One or more grooves including exposed sides;
The first semiconductor layer including a first electrode pad and a first finger extending from the first electrode pad, the first finger being electrically connected to the first semiconductor layer, A first electrode directly connected; And
And a second electrode electrically connected to the second semiconductor layer. The method according to claim 1,
The first finger is directly connected to the upper surface of the first semiconductor layer exposed at the bottom surface of the groove, and the first electrode pad is disposed on the second semiconductor layer. The method according to claim 1,
A second semiconductor layer disposed on the upper surface of the light emitting structure and having an edge that surrounds the at least one side surface of the mesa-etched structure, and an upper surface of the exposed first semiconductor layer And an insulating layer extending from the light emitting element. The method of claim 3,
Wherein the overlapping interval between the upper surface of the first semiconductor layer and the insulating layer is 4 占 퐉 to 8 占 퐉. The method according to claim 1,
And the first finger and the first electrode pad are directly connected to the upper surface of the first semiconductor layer. The method according to claim 1,
And the length of the groove is 20 占 퐉 to 90 占 퐉. The method according to claim 1,
And the width of the first finger is 3 占 퐉 to 7 占 퐉. The method according to claim 1,
And the first finger connected to the first semiconductor layer exposed from the bottom surface of the groove is exposed at a side surface of the light emitting structure. The method according to claim 1,
And the grooves have different lengths when the grooves are two or more. 10. The method of claim 9,
And the length of the groove is gradually increased or decreased as the distance from the first electrode pad is increased. The method of claim 3,
Wherein a distance between an edge of the insulating layer surrounding the at least one side surface of the mesa-etched light-emitting structure and an edge of the substrate is 5 占 퐉 to 20 占 퐉. The method according to claim 1,
And a current blocking layer disposed between the second electrode and the second semiconductor layer,
The width of the second electrode is narrower than the width of the current blocking layer, the edge of the second electrode is located inside the edge of the current blocking layer, and the difference between the width of the second electrode and the width of the current blocking layer is 20 Mu m or less. Board;
A light emitting structure disposed on the substrate, the light emitting structure including a first semiconductor layer, an active layer, and a second semiconductor layer, wherein at least one side of the four sides is mesa-etched to expose an upper surface of the first semiconductor layer;
A bottom surface that is recessed inward from the at least one side of the light emitting structure and exposes an upper surface of the first semiconductor layer and a side surface of the first semiconductor layer, One or more grooves including exposed sides;
The first semiconductor layer including a first electrode pad and a first finger extending from the first electrode pad, the first finger being electrically connected to the first semiconductor layer, A first electrode directly connected; And
And a second electrode electrically connected to the second semiconductor layer,
Wherein the first finger has a different width from a region overlapping the upper surface of the light emitting structure between adjacent grooves and a region connected to the first semiconductor layer. 14. The method of claim 13,
Wherein the first finger has a width greater than a width of a region connected to the first semiconductor layer and a width of a region overlapping the upper surface of the light emitting structure between adjacent grooves. 15. The method of claim 14,
Wherein the first finger has a protrusion protruding from the edge in a region where the first semiconductor layer and the first finger are in contact with each other. 14. The method of claim 13,
And the length of the groove is 20 占 퐉 to 90 占 퐉. 14. The method of claim 13,
And the width of the first finger is 3 占 퐉 to 7 占 퐉. 14. The method of claim 13,
And the width of the protrusion is less than 28.5 占 퐉. 14. The method of claim 13,
And the grooves have different lengths when the grooves are two or more. 20. The method of claim 19,
And the length of the groove is gradually increased or decreased as the distance from the first electrode pad is increased.

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