KR20120019750A - Light emitting device - Google Patents

Abstract

PURPOSE: A light emitting device is provided to improve ohmic contact properties by arranging nitride vanadium by combining vanadium of an ohmic layer and nitrogen of a nitrogen-opposing surface. CONSTITUTION: A junction layer(170) is arranged on a conductive supporting substrate(175). A reflective layer(160) is arranged on the junction layer. A light emitting structure layer(135) which generates light is arranged on the reflective layer. The light emitting structure layer comprises a first conductivity type semiconductor layer(110), an active layer(120), and a second conductivity type semiconductor layer(130). An electrode(115) an ohmic layer(114) including vanadium are arranged on the light emitting structure layer.

Description

[0001] LIGHT EMITTING DEVICE [0002]

The present disclosure relates to a light emitting device.

Light emitting diodes (LEDs) are a type of semiconductor device that converts electrical energy into light. The light emitting diode has advantages of low power consumption, semi-permanent life, fast response speed, safety and environmental friendliness compared to conventional light sources such as fluorescent and incandescent lamps.

Therefore, many researches are being made to replace the existing light sources with light emitting diodes, and the use of light emitting devices as light sources for lighting devices such as various lamps, liquid crystal displays, electronic signs, and street lamps that are used indoors and outdoors is increasing. to be.

The embodiment provides a light emitting device capable of improving reliability.

The light emitting device according to the embodiment includes a substrate; A light emitting structure layer including a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer disposed between the first conductive semiconductor layer and the second conductive semiconductor layer on the substrate; An ohmic layer including vanadium (V) on the light emitting structure layer; And an electrode on the ohmic layer.

According to an embodiment, the ohmic layer may include vanadium to improve ohmic contact characteristics. That is, the ohmic contact characteristics can be improved by vanadium nitride formed by combining nitrogen on the surface of the nitrogen facing the ohmic layer and vanadium on the ohmic layer.

In addition, a nitrogen cavity is formed in the first conductive semiconductor layer so that the charge of the first conductive semiconductor layer can be easily transferred to the conductive band. Thereby, the light emission characteristic of a light emitting element can be improved.

Furthermore, it is possible to prevent the light emitting element from changing the operating voltage at high voltage after aging.

1 is a cross-sectional view of a light emitting device according to an embodiment.
2 to 11 are cross-sectional views illustrating a process of a method of manufacturing a light emitting device according to the embodiment.
12 is a voltage-current graph before and after aging of the light emitting devices according to Experimental Example 1 and Comparative Example 1. FIG.
13 is a current-voltage graph of light emitting devices according to Experimental Examples 2 to 4 and Comparative Example 2. FIG.
14 is a cross-sectional view of a light emitting device package including a light emitting device according to the embodiment.
15 is a view illustrating a backlight unit including a light emitting device package according to an embodiment.
16 is a view illustrating a lighting unit including a light emitting device package according to an embodiment.

In the description of embodiments, each layer, region, pattern, or structure may be “on” or “under” the substrate, each layer, region, pad, or pattern. Substrate formed in ”includes all formed directly or through another layer. Criteria for the top / bottom or bottom / bottom of each layer will be described with reference to the drawings.

The thickness or the size of each layer (film), region, pattern or structure in the drawings may be modified for clarity and convenience of explanation, and thus does not entirely reflect the actual size.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view of a light emitting device according to an embodiment.

Referring to FIG. 1, the light emitting device 100 according to the present exemplary embodiment may include a conductive support substrate 175, a light emitting structure layer 135 that generates light on the conductive support substrate 175, and the light emitting structure layer 135. ) An ohmic layer 114 and an electrode 115. The light emitting structure layer 135 includes a first conductive semiconductor layer 110, an active layer 120, and a second conductive semiconductor layer 130, and is provided from the first and second conductive semiconductor layers 110 and 130. The electrons and holes may be recombined in the active layer 120 to generate light.

Between the conductive support substrate 175 and the light emitting structure layer 135, the bonding layer 170, the reflective layer 160, the ohmic layer 150, the current blocking layer (CBL) 145, and the protective member 140 ) And the passivation layer 180 may be formed on the side surface of the light emitting structure layer 135. This will be described in more detail as follows.

The conductive support substrate 175 may support the light emitting structure layer 135 and provide power to the light emitting structure layer 135 together with the electrode 115. The conductive support substrate 175 may include, for example, at least one of Cu, Au, Ni, Mo, Cu-W, Si, Ge, GaAs, ZnO, or SiC. However, the embodiment is not limited thereto, and an insulating substrate may be used instead of the conductive support substrate 175, and a separate electrode may be formed.

The conductive support substrate 175 may have a thickness of 30 μm to 500 μm. However, the embodiment is not limited thereto and may vary depending on the design of the light emitting device 100.

The bonding layer 170 may be formed on the conductive support substrate 175. The bonding layer 170 may be formed under the reflective layer 160 and the protection member 140 as a bonding layer. The bonding layer 170 exposes an outer surface thereof and contacts the reflective layer 160, the end of the ohmic layer 150, and the protective member 140, such that the reflective layer 160, the ohmic layer 150, and the protective member 140 are exposed to each other. It can strengthen the adhesion between.

The bonding layer 170 includes a barrier metal or a bonding metal. For example, the bonding layer 170 may include at least one of Ti, Au, Sn, Ni, Cr, Ga, In, Bi, Cu, Al, Si, Ag, Ta, and alloys thereof.

The reflective layer 160 may be formed on the bonding layer 170. The reflective layer 160 may reflect light emitted from the light emitting structure layer 135 toward the reflective layer 160, thereby improving light emission efficiency of the light emitting device 100.

For example, the reflective layer 160 may include at least one of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, Hf, or an alloy thereof. In addition, the reflective layer 160 includes the above-described metal or alloy, indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IZO), and indium gallium tin oxide (IGTO). ), It may be formed in multiple layers using a light transmitting conductive material such as indium gallium zinc oxide (IGZO), aluminum zinc oxide (AZO), antimony tin oxide (ATO), and the like. For example, the reflective layer 160 may include a stacked structure of IZO / Ni, AZO / Ag, IZO / Ag / Ni, AZO / Ag / Ni, Ag / Cu, Ag / Pd / Cu, and the like.

The ohmic layer 150 may be formed on the reflective layer 160. The ohmic layer 150 is in ohmic contact with the second conductive semiconductor layer 130 so that power can be smoothly supplied to the light emitting structure layer 135. The ohmic layer 150 includes ITO, IZO, IZTO, IAZO, IGZO, IGTO, AZO, ATO, gallium zinc oxide (GZO), IrO _x , RuO _x , RuO _x / ITO, Ni, Ag, Pt, Ni / IrO using at least one of _x / Au, or Ni / IrO _x / Au / ITO can be implemented as a single layer or multiple layers.

 As described above, the upper surface of the reflective layer 160 is illustrated in contact with the ohmic layer 150. However, it is also possible for the reflective layer 160 to contact the protective member 140, the current blocking layer 145, or the light emitting structure layer 135.

A current blocking layer 145 may be formed between the first ohmic layer 150 and the second conductive semiconductor layer 130. An upper surface of the current blocking layer 145 may contact the second conductive semiconductor layer 130, and a lower surface and a side surface of the current blocking layer 145 may contact the ohmic layer 150.

The current blocking layer 145 may be formed to overlap at least a portion of the electrode 115 in the vertical direction, thereby alleviating a phenomenon in which current is concentrated at the shortest distance between the electrode 115 and the conductive support substrate 175. The luminous efficiency of the light emitting device 100 can be improved.

The current blocking layer 145 may be formed of a material having electrical insulation, a material having a lower electrical conductivity than the reflective layer 160 or the bonding layer 170, or a material forming Schottky contact with the second conductive semiconductor layer 130. Can be formed. For example, the current blocking layer 145 includes ITO, IZO, IZTO, IAZO, IGZO, IGTO, AZO, ATO, ZnO, SiO ₂ , SiO _x , SiO _x N _y , Si ₃ N ₄ , Al ₂ O ₃ , TiO _x , TiO ₂ , Ti, Al, or Cr.

As described above, the ohmic layer 150 contacts the bottom and side surfaces of the current blocking layer 145, but is not limited thereto. Therefore, the ohmic layer 150 and the current blocking layer 145 may be spaced apart from each other, or the ohmic layer 150 may contact only the side surface of the current blocking layer 145. Alternatively, the current blocking layer 145 may be formed between the reflective layer 160 and the ohmic layer 150.

The protection member 140 may be formed in the circumferential region of the upper surface of the bonding layer 170 described above. That is, the protection member 140 may be formed in the circumferential region between the light emitting structure layer 135 and the bonding layer 170, thereby forming a ring shape, a loop shape, a frame shape, or the like. A portion of the protection member 140 may overlap the light emitting structure layer 135 in the vertical direction.

The protection member 140 may increase the distance between the bonding layer 170 and the active layer 120 at the side, thereby reducing the possibility of the electrical short between the bonding layer 170 and the active layer 120. In addition, the protection member 140 may also prevent moisture or the like from penetrating into the gap between the light emitting structure layer 135 and the conductive support member 175.

In addition, the protection member 140 may prevent the occurrence of an electrical short in the chip separation process. In more detail, when isolation etching is performed to separate the light emitting structure layer 135 into the unit chip region, the fragments generated in the bonding layer 170 may be separated from the second conductive semiconductor layer 130. An electrical short may occur between the active layer 120 or between the active layer 120 and the first conductive semiconductor layer 110, and the protection member 140 may prevent the electrical short. Accordingly, the protection member 140 may be formed of a material that does not break or cause fragments during the isolation etching, or an insulating material that does not cause an electrical short even if a very small portion or a small amount of fragments is generated.

The protective member 140 may be formed of a material having electrical insulation, a material having a lower electrical conductivity than the reflective layer 160 or the bonding layer 170, or a material forming Schottky contact with the second conductive semiconductor layer 130. Can be formed. For example, the protective member 140 may include ITO, IZO, IZTO, IAZO, IGZO, IGTO, AZO, ATO, ZnO, SiO ₂ , SiO _x , SiO _x N _y , Si ₃ N ₄ , Al ₂ O ₃ , It may include at least one of TiO _x , TiO ₂ , Ti, Al or Cr.

The light emitting structure layer 135 may be formed on the ohmic layer 150 and the protection member 140. Side surfaces of the light emitting structure layer 135 may be inclined by an isolation etching that divides the plurality of chips into unit chip regions.

The light emitting structure layer 135 may include a compound semiconductor layer of a plurality of group III-V elements, the first conductive semiconductor layer 110, the second conductive semiconductor layer 130, and an active layer disposed therebetween. 120 may be included. In this case, the second conductive semiconductor layer 130 is positioned on the first ohmic layer 150 and the protection member 140, and the active layer 120 is positioned on the second conductive semiconductor layer 130. The type semiconductor layer 110 may be located on the active layer 120.

The first conductivity type semiconductor layer 110 may include a compound semiconductor of a group III-V element doped with the first conductivity type dopant. For example, the first conductivity-type semiconductor layer 110 may include an n-type semiconductor layer. The n-type semiconductor layer is an n-type dopant in a semiconductor material having a compositional formula of _{In x Al y Ga 1 -x- y} N (0≤x≤1, 0 ≤y≤1, 0≤x + y≤1) doped Can be formed. For example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaP, GaAs, GaAsP, AlGaInP, etc. may include n-type dopants such as Si, Ge, Sn, Se, Te, and the like. The first conductivity type semiconductor layer 110 may be formed as a single layer or a multilayer, but is not limited thereto.

The active layer 120 may be formed of any one of a single quantum well structure, a multi quantum well structure (MQW), a quantum dot structure, or a quantum line structure, but is not limited thereto.

The active layer 120 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 + y ≦ 1). When the active layer 120 is formed in a multi-quantum well structure, the active layer 120 may be formed by stacking a plurality of well layers and a plurality of barrier layers. For example, the active layer 120 may be formed by alternately stacking a well layer including InGaN and a barrier layer including GaN.

A clad layer (not shown) doped with an n-type or p-type dopant may be formed on and / or under the active layer 120, and the clad layer may include an AlGaN layer or an InAlGaN layer.

The second conductivity type semiconductor layer 130 may include a compound semiconductor of a group III-V element doped with the second conductivity type dopant. For example, the second conductivity-type semiconductor layer 130 may include a p-type semiconductor layer. The p-type semiconductor layer is a p-type dopant doped into the semiconductor material having a compositional formula of _{In x Al y Ga 1 -x- y} N (0≤x≤1, 0 ≤y≤1, 0≤x + y≤1) Can be formed. For example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaP, GaAs, GaAsP, AlGaInP, etc. may be formed by including p-type dopants such as Mg, Zn, Ca, Sr, Br and the like. The second conductivity-type semiconductor layer 130 may be formed as a single layer or a multilayer, but is not limited thereto.

In the above description, the first conductive semiconductor layer 110 includes an n-type semiconductor layer and the second conductive semiconductor layer 130 includes a p-type semiconductor layer. However, the embodiment is not limited thereto. Accordingly, the first conductivity type semiconductor layer 110 may include a p-type semiconductor layer and the second conductivity type semiconductor layer 130 may include an n-type semiconductor layer. In addition, another n-type or p-type semiconductor layer (not shown) may be formed under the second conductivity-type semiconductor layer 130. Accordingly, the light emitting structure layer 135 may have at least one of np, pn, npn, and pnp junction structures. In addition, the doping concentrations of the dopants in the first conductive semiconductor layer 110 and the second conductive semiconductor layer 130 may be uniform or non-uniform. That is, the structure of the light emitting structure layer 135 may be variously modified, but embodiments are not limited thereto.

The light extraction pattern 112 may be formed on the top surface of the light emitting structure layer 135. The light extraction pattern 112 may improve the light extraction efficiency of the light emitting device 100 by minimizing the amount of light totally reflected from the surface. The light extraction pattern 112 may have a random shape and arrangement, or may be formed to have a desired shape and arrangement.

For example, the light extraction pattern 112 may be formed by arranging a photonic crystal structure having a period of 50 nm to 3000 nm. The photonic crystal structure can efficiently extract light of a specific wavelength region to the outside by an interference effect or the like.

In addition, the light extraction pattern 112 may be formed to have various shapes such as a cylinder, a polygonal pillar, a cone, a polygonal pyramid, a truncated cone, a polygonal truncated cone, but is not limited thereto.

The ohmic layer 114 and the electrode 115 are formed on the light emitting structure layer 135, more specifically, the first conductivity type semiconductor layer 110.

A first conductive type semiconductor layer 110 as described above has a composition formula of _{In x Al y Ga 1 -x- y} N (0≤x≤1, 0 ≤y≤1, 0≤x + y≤1) A semiconductor layer (eg, n-type gallium nitride (GaN)) may be included, and one surface on which the ohmic layer 114 is located may have an N-face surface. The ohmic layer 114 includes vanadium (V). For example, the ohmic layer 114 may include only vanadium and other inevitable materials.

Accordingly, the vanadium and the first conductivity type semiconductor layer 110 of the ohmic layer 114 are located near the interface between the ohmic layer 114 and the light emitting structure layer 135, more precisely, the first conductivity type semiconductor layer 110. Nitrogen vanadium nitride (VN) is formed. By this vanadium nitride, the ohmic contact characteristic of the electrode 115 can be improved. As a result, the operating voltage of the light emitting device 100 may be lowered, thereby improving efficiency. Furthermore, in the related art, the phenomenon in which the operating voltage changes at a high voltage after aging has occurred, but in the present embodiment, the operating voltage may hardly change. This will be described in more detail later with reference to FIGS. 2 and 3.

In addition, an N vacancy is formed in the first conductive semiconductor layer 110 so that the charge of the first conductive semiconductor layer 110 can be easily transferred to the conductive band. Thereby, the light emission characteristic of the light emitting element 100 can be improved.

The thickness of the ohmic layer 114 may be 0.5 nm to 1000 nm. When the thickness of the ohmic layer 114 is less than 0.5 nm, the effect of improving ohmic contact characteristics may be reduced. In addition, when the thickness of the ohmic layer 114 exceeds 1000 nm, there is a problem in that manufacturing cost and time are increased, and a problem due to brittle vanadium may occur.

The electrodes 115 formed on the ohmic layer 114 are Au, Pd, Pt, Ru, Re, Mg, Zn, Hf, Ta, Rh, Ir, W, Ti, Ag, Cr, Mo, Nb, Al, Ni, Cu, WTi or an alloy thereof may be included.

For example, the electrode 115 may include a first layer 115a, a second layer 115b, a third layer 115c, and a fourth layer 115d that are sequentially stacked on the ohmic layer 114. have. The first layer 115a and the third layer 115c include Ni or Al to function as a barrier layer. That is, the first layer 115a and the third layer 115c serve to prevent the materials of the ohmic layer 114, the second layer 115b, and the fourth layer 115d from mixing with each other. The second layer 115b includes Cu so that the electrode 115 can have an appropriate thickness. The fourth layer 115d includes Au to improve wire bonding characteristics.

However, the embodiment is not limited thereto, and the electrode may be made of a single layer such as a W layer, a WTi layer, a Ti layer, an Al layer, or an Ag layer.

The electrode 115 may include a pad portion to which wire bonding is performed and an electrode portion extending from the pad portion. The electrode part may be branched in a predetermined pattern shape.

Since the light extraction pattern 112 is formed on the upper surface of the first conductivity type semiconductor layer 110, the pattern corresponding to the light extraction pattern 112 is also formed on the upper surface of the ohmic layer 114 and the electrode 115 by a manufacturing process. This can be formed naturally. However, the present invention is not limited thereto.

The passivation layer 180 may be formed on at least a side of the light emitting structure layer 135. In addition, the passivation layer 180 may be formed on the top surface of the first conductivity type semiconductor layer 110 and the top surface of the protection member 140, but is not limited thereto.

Hereinafter, a method of manufacturing the light emitting device 100 according to the embodiment will be described in detail. However, the same or very similar contents to those described above will be omitted or briefly described.

2 to 11 are cross-sectional views illustrating a process of a method of manufacturing a light emitting device according to the embodiment.

As shown in FIG. 2, the light emitting structure layer 135 is formed on the growth substrate 101.

The growth substrate 101 may include, for example, at least one of sapphire (Al ₂ O ₃ ), Si, SiC, GaAs, GaN, ZnO, MgO, GaP, InP, and Ge. However, the embodiment is not limited thereto, and the growth substrate 101 made of various materials may be used.

The light emitting structure layer 135 may be formed by sequentially growing the first conductive semiconductor layer 110, the active layer 120, and the second conductive semiconductor layer 130 on the growth substrate 101.

The light emitting structure layer 135 may include, for example, metal organic chemical vapor deposition (MOCVD), chemical vapor deposition (CVD), and plasma-enhanced chemical vapor deposition (PECVD). It may be formed using a method such as molecular beam growth (MBE), hydride vapor phase growth (HVPE) and the like. However, this is not limitative.

Meanwhile, a buffer layer and / or an undoped nitride layer (not shown) may be formed between the light emitting structure layer 135 and the growth substrate 101 to alleviate the lattice constant difference.

Next, as illustrated in FIG. 3, the protection member 140 may be selectively formed on the light emitting structure layer 135 corresponding to the unit chip region. The protection member 140 may be formed around the unit chip area by using the patterned mask. The protective member 140 may be formed using various deposition methods such as electron beam (E-beam) deposition, sputtering, and PECVD.

Subsequently, as illustrated in FIG. 4, the current blocking layer 145 may be formed on the second conductivity-type semiconductor layer 130. The current blocking layer 145 may be formed using a mask pattern.

In FIGS. 3 and 4, the protection member 140 and the current blocking layer 145 are formed in separate processes, but the protection member 140 and the current blocking layer 145 are formed of the same material to form a single process. It is also possible to form at the same time. For example, after forming the SiO ₂ layer on the second conductivity-type semiconductor layer 130, the protective member 140 and the current blocking layer 145 may be simultaneously formed using a mask pattern.

Subsequently, as shown in FIG. 5, the ohmic layer 150 and the reflective layer 160 may be sequentially formed on the second conductivity-type semiconductor layer 130 and the current blocking layer 145.

The ohmic layer 150 and the reflective layer 160 may be formed by, for example, any one of electron beam (E-beam) deposition, sputtering, and PECVD.

6 and 7, the conductive support substrate 175 is bonded to the structure of FIG. 5 via the bonding layer 170. The bonding layer 170 may be in contact with the reflective layer 160, the end of the ohmic layer 150, and the protective member 140 to strengthen the adhesive force therebetween.

In the above-described embodiment, although the conductive support substrate 175 is illustrated as being bonded through the bonding layer 170, the conductive support substrate 175 is plated or deposited without forming the bonding layer 170. It is also possible to form in a manner.

Next, as shown in FIG. 8, the growth substrate 101 is removed from the light emitting structure layer 135. In FIG. 8, the structure illustrated in FIG. 7 is shown upside down.

The growth substrate 101 may be removed by a laser lift off method or a chemical lift off method.

Next, as illustrated in FIG. 9, the light emitting structure layer 135 is isolated by a unit chip region and separated into a plurality of light emitting structure layers 135. For example, the isolation etching may be performed by a dry etching method such as inductively coupled plasma (ICP).

Subsequently, as shown in FIG. 10, the passivation layer 180 is formed on the protective member 140 and the light emitting structure layer 135, and the passivation layer (eg, the upper surface of the first conductivity-type semiconductor layer 110 is exposed). Selectively remove 180). The light extraction pattern 112 is formed on the upper surface of the first conductivity type semiconductor layer 110 to improve light extraction efficiency. The light extraction pattern 112 may be formed by a wet etching process or a dry etching process.

Next, as illustrated in FIG. 11, an ohmic layer 114 and an electrode 115 including vanadium are formed on the light extraction pattern 112.

The ohmic layer 114 and the electrode 115 including vanadium may be formed by a method such as sputtering or electron beam deposition. The ohmic layer 114 and the electrode 115 may be formed by using a mask, or may be formed by patterning together the layers constituting the ohmic layer 114 and the electrode 115.

In addition, when the structure of FIG. 11 is separated into a unit chip region through a chip separation process, a plurality of light emitting devices may be manufactured.

The chip separation process may include, for example, a breaking process of separating a chip by applying a physical force using a blade, a laser scrubbing process of separating a chip by irradiating a laser to a chip boundary, and etching including wet or dry etching. Process and the like. The embodiment is not limited thereto.

Hereinafter, the light emitting device according to the embodiment will be described in more detail with reference to the experimental examples. These experimental examples are only examples for clarity of explanation, and the embodiments are not limited thereto.

First, with reference to Figure 12 looks at Experimental Example 1 and Comparative Example 1.

Experimental Example  One

a second conductive type including a first conductive semiconductor layer including an n-type gallium nitride (GaN) and a nitrogen-facing surface, an active layer in which an InGaN well layer / AlGaN barrier layer is sequentially stacked, and a p-type gallium nitride (GaN) The light emitting structure layer including the semiconductor layer was formed. An ohmic layer containing vanadium was formed on the nitrogen facing surface of the first conductive semiconductor layer to a thickness of 1.5 mm by sputtering, and an electrode having a stacked structure of Ni / Cu / Ni / Au was formed thereon to form a light emitting device. Prepared.

Comparative example  One

A light emitting device was manufactured in the same manner as in Experiment 1, except that an ohmic layer having a thickness of 1.5 mm including chromium was formed by sputtering.

The voltage-current graphs of the light emitting devices of Experimental Example 1 and Comparative Example 1 before aging and the voltage-current graphs of the light emitting devices of Experimental Example 1 and Comparative Example 1 after aging are shown in FIG. 12. Aging was performed for 5 hours at a current density of 120 A / cm ² .

12, in Experimental Example 1 using vanadium as an ohmic layer, it can be seen that there is almost no difference in voltage-current graph before and after aging. That is, it can be seen that there is no change in the operating voltage before and after aging. On the other hand, in Comparative Example 1 in which chromium was used as the ohmic layer, it can be seen that the current is decreased at high voltage after aging and the operating voltage is changed.

As such, it can be seen that the light emitting device according to Experimental Example 1 may have excellent characteristics with little change in operating voltage even at high voltage.

Next, with reference to Figure 13 looks at with respect to Experimental Examples 2 to 4 and Comparative Example 2.

Experimental Example  2

A light emitting device was manufactured according to the same method as Experimental Example 1 except that an ohmic layer including vanadium was formed to a thickness of 2 nm.

Experimental Example  3

A light emitting device was manufactured according to the same method as Experimental Example 1 except that an ohmic layer including vanadium was formed to a thickness of 5 nm.

Experimental Example  4

A light emitting device was manufactured according to the same method as Experimental Example 1 except that an ohmic layer including vanadium was formed to a thickness of 10 nm.

Comparative example  2

A light emitting device was manufactured in the same manner as in Comparative Example 1, except that an ohmic layer including chromium was formed to a thickness of 2 nm.

13 illustrates current-voltage graphs of light emitting devices according to Experimental Examples 2 to 4 and Comparative Example 2. FIG.

Referring to FIG. 13, it can be seen that the light emitting device according to Experimental Examples 2 to 4 has a lower voltage than the light emitting device according to Comparative Example 2 at the same current. As such, it can be seen that the light emitting devices according to Experimental Examples 2 to 4 have lower voltage characteristics than Comparative Example 2, thereby improving efficiency. Since the lower voltage characteristics in the order of Experimental Example 2, Experimental Example 3, Experimental Example 4, it can be seen that the thicker the ohmic layer, the better the voltage characteristic.

Hereinafter, a light emitting device package including a light emitting device according to the present embodiment will be described with reference to FIG. 14. 14 is a cross-sectional view of a light emitting device package including a light emitting device according to the embodiment.

Referring to FIG. 14, the light emitting device package according to the embodiment includes a package body 30, a first electrode layer 31 and a second electrode layer 32 provided on the package body 30, and the package body 30. The light emitting device 100 is installed at and electrically connected to the first and second electrode layers 31 and 32, and a molding member 40 surrounding the light emitting device 100.

The package body 30 may be formed of a resin such as polyphthal amide (PPA), liquid crystal polymer (LCP), polyamide 9T (polyamid9T, PA9T), metal, photo sensitive glass, sapphire ( Al ₂ O ₃ ), ceramics, and printed circuit boards (PCBs). However, the present embodiment is not limited to these materials.

The package body 30 is formed with a cavity 34 whose top is opened. The sides of the cavity 34 may be perpendicular or inclined to the bottom surface of the cavity 34.

In the package body 30, a first electrode layer 31 and a second electrode layer 32 electrically connected to the light emitting device 100 are disposed. The first electrode layer 31 and the second electrode layer 32 may be formed of a metal plate having a predetermined thickness, and another metal layer may be plated on this surface. The first electrode layer 31 and the second electrode layer 32 may be made of a metal having excellent conductivity. Such metals include titanium (Ti), copper (Cu), nickel (Ni), gold (Au), chromium (Cr), tantalum (Ta), platinum (Pt), tin (Sn), silver (Ag), and the like. There is this.

The first and second electrode layers 31 and 32 provide power to the light emitting device 100. In addition, the first and second electrode layers 31 and 32 may serve to increase light efficiency by reflecting light generated from the light emitting device 100, and discharge heat generated from the light emitting device 100 to the outside. It can also play a role.

The light emitting device 100 is positioned in the cavity 34 while being electrically connected to the first electrode layer 31 and the second electrode layer 32. The light emitting device 100 may be electrically connected to the first electrode layer 31 and the second electrode layer 32 by any one of a wire method, a flip chip method, or a die bonding method. In the embodiment, the light emitting device 100 is electrically connected to the first electrode layer 31 through the wire 50 and directly connected to the second electrode layer 32.

The molding member 40 may be formed while surrounding the light emitting device 100 to protect the light emitting device 100. In addition, the molding member 40 may include a phosphor to change the wavelength of light emitted from the light emitting device 100.

The light emitting device package according to the above-described embodiments and modifications may function as a lighting system such as a backlight unit, an indicator device, a lamp, and a street lamp. This will be described with reference to FIGS. 15 and 16.

15 is a view illustrating a backlight unit including a light emitting device package according to an embodiment. However, the backlight unit 1100 of FIG. 15 is an example of an illumination system, and is not limited thereto.

Referring to FIG. 15, the backlight unit 1100 may be disposed on the bottom cover 1140, the light guide member 1120 disposed in the bottom cover 1140, and at least one side or the bottom surface of the light guide member 1120. The light emitting module 1110 may be included. In addition, a reflective sheet 1130 may be disposed under the light guide member 1120.

The bottom cover 1140 may be formed in a box shape having an upper surface open to accommodate the light guide member 1120, the light emitting module 1100, and the reflective sheet 1130, and may be formed of metal or resin. Can be. However, the present invention is not limited thereto.

The light emitting module 1110 may include a plurality of light emitting device packages 600 mounted on the substrate 700. The plurality of light emitting device packages 600 provides light to the light guide member 1120.

As shown, the light emitting module 1110 may be disposed on at least one of the inner surfaces of the bottom cover 1140, thereby providing light toward at least one side of the light guide member 1120. .

However, the light emitting module 1110 may be disposed under the light guide member 1120 in the bottom cover 1140 to provide light toward the bottom surface of the light guide member 1120. This may be variously modified according to the design of the backlight unit 1100.

The light guide member 1120 may be disposed in the bottom cover 1140. The light guide member 1120 may surface-light the light provided from the light emitting module 1110 and guide the light guide member to a display panel (not shown).

The light guide member 1120 may be, for example, a light guide panel (LGP). The light guide plate may be, for example, an acrylic resin such as polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), a cyclic olefin copolymer (COC), or a polycarbonate (PC). It may be formed of one of polyethylene naphthalate resin.

The optical sheet 1150 may be disposed above the light guide member 1120.

The optical sheet 1150 may include at least one of, for example, a diffusion sheet, a light collecting sheet, a luminance rising sheet, and a fluorescent sheet. For example, the optical sheet 1150 may be formed by stacking a diffusion sheet, a light collecting sheet, a luminance rising sheet, and a fluorescent sheet. In this case, the diffusion sheet 1150 evenly diffuses the light emitted from the light emitting module 1110, and the diffused light may be focused onto a display panel (not shown) by the light collecting sheet. At this time, the light emitted from the light collecting sheet is light that is randomly polarized. The luminance rising sheet can increase the degree of polarization of light emitted from the light collecting sheet. The light collecting sheet can be, for example, a horizontal or / and vertical prism sheet. In addition, the brightness rising sheet may be, for example, a dual brightness enhancement film. In addition, the fluorescent sheet may be a translucent plate or film containing phosphors.

The reflective sheet 1130 may be disposed under the light guide member 1120. The reflective sheet 1130 may reflect light emitted through the lower surface of the light guide member 1120 toward the exit surface of the light guide member 1120. The reflective sheet 1130 may be formed of a resin having good reflectance, for example, PET, PC, poly vinyl chloride, resin, or the like, but is not limited thereto.

16 is a view illustrating a lighting unit including a light emitting device package according to an embodiment. However, the lighting unit 1200 of FIG. 16 is an example of a lighting system, but is not limited thereto.

Referring to FIG. 16, the lighting unit 1200 includes a case body 1210, a light emitting module 1230 installed in the case body 1210, and a connection terminal installed in the case body 1210 and receiving power from an external power source. 1220.

The case body 1210 is preferably formed of a material having good heat dissipation, for example, may be formed of a metal or a resin.

The light emitting module 1230 may include a substrate 700 and at least one light emitting device package 600 mounted on the substrate 700.

The substrate 700 may be a circuit pattern printed on the insulator, for example, a printed circuit board (PCB), a metal core PCB, a flexible PCB, a ceramic PCB, and the like. It may include.

In addition, the substrate 700 may be formed of a material that efficiently reflects light, or the surface may be formed of a color in which the light is efficiently reflected, for example, white, silver, or the like.

At least one light emitting device package 600 may be mounted on the substrate 700.

Each of the light emitting device packages 600 may include at least one light emitting diode (LED). The light emitting device may include a colored light emitting device for emitting colored light of red, green, blue or white color, and a UV light emitting device for emitting ultraviolet light (UV, UltraViolet).

The light emitting module 1230 may be arranged to have a combination of various light emitting devices to obtain color and luminance. For example, the white light emitting device, the red light emitting device, and the green light emitting device may be combined to secure high color rendering (CRI). In addition, a fluorescent sheet may be further disposed on a traveling path of light emitted from the light emitting module 1230, and the fluorescent sheet changes the wavelength of light emitted from the light emitting module 1230. For example, when the light emitted from the light emitting module 1230 has a blue wavelength band, the fluorescent sheet may include a yellow phosphor, and the light emitted from the light emitting module 1230 may be finally viewed as white light after passing through the fluorescent sheet. do.

The connection terminal 1220 may be electrically connected to the light emitting module 1230 to supply power. According to FIG. 16, the connection terminal 1220 is inserted into and coupled to an external power source in a socket manner, but is not limited thereto. For example, the connection terminal 1220 may be formed in a pin shape and inserted into an external power source, or may be connected to the external power source by wiring.

In the lighting system as described above, at least one of a light guide member, a diffusion sheet, a light collecting sheet, a luminance rising sheet, and a fluorescent sheet may be disposed on a propagation path of light emitted from the light emitting module to obtain a desired optical effect.

As described above, the lighting system includes a light emitting device package having excellent voltage characteristics, and thus may have excellent light efficiency and characteristics.

The features, structures, effects and the like described in the foregoing embodiments are included in at least one embodiment of the present invention and are not necessarily limited to one embodiment. In addition, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified with respect to other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

In addition, the above description has been made with reference to the embodiments, which are merely examples and are not intended to limit the invention. It will be appreciated that various modifications and applications are possible. For example, each component specifically shown in the embodiments may be modified and implemented. It is to be understood that the present invention may be embodied in many other specific forms without departing from the spirit or essential characteristics thereof.

Claims (12)

Board;
A light emitting structure layer including a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer disposed between the first conductive semiconductor layer and the second conductive semiconductor layer on the substrate;
An ohmic layer including vanadium (V) on the light emitting structure layer; And
An electrode on the ohmic layer
Light emitting device comprising a. The method of claim 1,
The light emitting structure layer, includes a semiconductor layer having a compositional formula of _{In x Al y Ga 1 -x- y} N (0≤x≤1, 0 ≤y≤1, 0≤x + y≤1),
The light emitting device of claim 1, wherein one surface of the light emitting structure layer in contact with the ohmic layer has an N-face surface. The method of claim 2,
And a vanadium nitride (VN) in which vanadium of the ohmic layer and nitrogen of the light emitting structure layer are positioned near an interface between the ohmic layer and the light emitting structure layer. The method of claim 1,
The second conductivity-type semiconductor layer is a p-type semiconductor layer, the first conductivity-type semiconductor layer is an n-type semiconductor layer,
A second conductive semiconductor layer, the active layer, and the first conductive semiconductor layer are sequentially formed on the substrate;
The ohmic layer is in contact with the first conductive semiconductor layer. The method of claim 4, wherein
Has a composition formula of the first conductive type semiconductor _{layer, In x Al y Ga 1 -x-} y N (0≤x≤1, 0 ≤y≤1, 0≤x + y≤1),
The light emitting device of claim 1, wherein one surface of the first conductivity-type semiconductor layer in contact with the ohmic layer has an N-face surface. The method of claim 1,
The thickness of the ohmic layer is a light emitting device of 0.5 nm to 1000 nm. The method of claim 1,
The electrode is Au, Pd, Pt, Ru, Re, Mg, Zn, Hf, Ta, Rh, Ir, W, Ti, Ag, Cr, Mo, Nb, Al, Ni, Cu, WTi and alloys thereof Light emitting device comprising at least one. The method of claim 1,
The electrode includes a first layer and a second layer sequentially stacked on the ohmic layer,
The first layer comprises Ni or Al,
A light emitting device in which the second layer comprises Cu. The method of claim 8,
The light emitting device further comprises a third layer including Ni or Al on the second layer. 10. The method of claim 9,
The light emitting device further comprises a fourth layer including Au on the third layer. The method of claim 1,
A light emitting device in which the substrate is a conductive support substrate. The method of claim 1,
And a current blocking layer disposed between the substrate and the light emitting structure layer and at least partially overlapping the electrode in a vertical direction.

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