KR20130061980A

KR20130061980A - Light emitting device

Info

Publication number: KR20130061980A
Application number: KR1020110128336A
Authority: KR
Inventors: 강동훈; 심상균; 윤호상; 손성진
Original assignee: 엘지이노텍 주식회사
Priority date: 2011-12-02
Filing date: 2011-12-02
Publication date: 2013-06-12

Abstract

PURPOSE: A light emitting device is provided to block the overflow of electrons by using an electron barrier layer, and to increase the recombination probability of holes and electrons. CONSTITUTION: An active layer(132) is arranged on a first conductive semiconductor layer(131). An electron barrier layer(140) is arranged on the active layer. The electron barrier layer has a first layer, a second layer, and a third layer. The electron barrier layer includes a p-type impurity. A second conductive semiconductor layer(133) is arranged on the electron barrier layer.

Description

[0001]

An embodiment relates to a light emitting element.

Light Emitting Diode (LED) is a device that converts an electric signal into a light form using the characteristics of a compound semiconductor, and is used for home appliances, remote controllers, electronic displays, indicators, and various automation devices. There is a trend.

In general, miniaturized LEDs are made of a surface mounting device for mounting directly on a PCB (Printed Circuit Board) substrate, and an LED lamp used as a display device is also being developed as a surface mounting device type . Such a surface mount device can replace a conventional simple lighting lamp, which is used for a lighting indicator for various colors, a character indicator, an image indicator, and the like.

As the usage area of the LED is widened as described above, the luminance required for a lamp used for living, a lamp for rescue signals, etc. increases, and thus, it is necessary to increase the luminous efficiency in order to increase the luminous luminance of the LED.

Such LEDs generate light by recombination of electrons and holes in the active layer, and the electron mobility is greater than that of the holes, forming an electron blocking layer to prevent electrons from overflowing the active layer to the p-type semiconductor layer. In addition, the luminous efficiency is increased.

On the other hand, Korean Patent Laid-Open Publication No. 10-2011-0090118 discloses an electron blocking layer including layers having different energy band gaps.

However, in the electron blocking layer, it is difficult to dop the p-type impurity at the beginning of growth, and there is a problem in that defects are caused by excessive doping of the p-type impurity between the electron blocking layer and the p-type semiconductor layer.

Embodiments provide an LED blocking layer including a plurality of layers having different amounts of Ga between an active layer and a p-type semiconductor layer, thereby increasing light emission efficiency.

The light emitting device according to the embodiment includes a first conductive semiconductor layer, an active layer positioned on the first conductive semiconductor layer, and a first layer, a second layer, and a third layer including Ga on the active layer. And a second conductive semiconductor layer positioned on the electron blocking layer and the electron blocking layer sequentially stacked, and along the stacking direction, the first layer and the third layer linearly increase the amount of Ga. And the second layer may linearly decrease in the amount of Ga.

The light emitting device according to the embodiment may increase the concentration of the p-type impurity doped at the beginning of the growth of the electron blocking layer, and may improve the interface characteristics between the electron blocking layer and the p-type semiconductor layer.

Therefore, the characteristics and the efficiency of the electron blocking layer can be increased, thereby improving the luminous efficiency of the light emitting device.

1 is a cross-sectional view illustrating a cross-sectional view of a horizontal light emitting device according to an embodiment, and FIG. 2 is an enlarged view of portion A of FIG. 1.
3 is a cross-sectional view showing a cross section of a vertical light emitting device according to the embodiment.
4 to 9 are views showing a manufacturing process of the light emitting device according to the embodiment.
10 is a cross-sectional view of a light emitting device package including the light emitting device according to the embodiment.
11A is a perspective view illustrating a lighting device including a light emitting device module according to an embodiment, and FIG. 11B is a cross-sectional view taken along line C ′ of the lighting device of FIG. 11A.
12 and 13 are exploded perspective views of a liquid crystal display device including an optical sheet according to an embodiment.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

The terms spatially relative, "below", "beneath", "lower", "above", "upper" May be used to readily describe a device or a relationship of components to other devices or components. Spatially relative terms should be understood to include, in addition to the orientation shown in the drawings, terms that include different orientations of the device during use or operation. For example, when flipping a device shown in the figure, a device described as "below" or "beneath" of another device may be placed "above" of another device. Thus, the exemplary term "below" can include both downward and upward directions. The device can also be oriented in other directions, so that spatially relative terms can be interpreted according to orientation.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. It is noted that the terms "comprises" and / or "comprising" used in the specification are intended to be inclusive in a manner similar to the components, steps, operations, and / Or additions.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used in a sense that can be commonly understood by those skilled in the art. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

The thickness and size of each layer in the drawings are exaggerated, omitted, or schematically shown for convenience and clarity of explanation. Also, the size and area of each component do not entirely reflect actual size or area.

Further, the angle and direction mentioned in the description of the structure of the light emitting device in the embodiment are based on those shown in the drawings. In the description of the structure of the light emitting device in the specification, reference points and positional relationship with respect to angles are not explicitly referred to, refer to the related drawings.

1 is a cross-sectional view illustrating a cross-sectional view of a horizontal light emitting device according to an embodiment, and FIG. 2 is an enlarged view of portion A of FIG. 1.

Referring to FIG. 1, the light emitting device 100 according to the embodiment includes a growth substrate 110, a buffer layer 120, a first conductivity type semiconductor layer 131, an active layer 132, an electron blocking layer 140, and a second substrate. The second conductive semiconductor layer 133 may include a first electrode 160 and a second electrode 150.

The growth substrate 110 may be formed of a conductive substrate or an insulating substrate. For example, sapphire (Al ₂ O ₃ ), SiC, Si, GaAs, GaN, ZnO, Si, GaP, InP, Ge, and Ga ₂ 0 It may be formed of at least one of _three . The growth substrate 110 may be wet-washed to remove impurities from the surface, and the growth substrate 110 may be patterned (Ptterned SubStrate, PSS) to improve light extraction efficiency, but is not limited thereto. .

The buffer layer 120 may be formed on the growth substrate 110 to mitigate lattice mismatch between the growth substrate 110 and the first conductive semiconductor layer 131 and to easily grow the conductive semiconductor layers.

The buffer layer 120 may be formed of AlInN / GaN stacked structure including AlN and GaN, InGaN / GaN stacked structure, and AlInGaN / InGaN / GaN stacked structure.

The light emitting structure 130 is positioned on the growth substrate 110 and includes a first conductive semiconductor layer 131, an active layer 132, an electron blocking layer 140, and a second conductive semiconductor layer 133. The active layer 132 may be interposed between the first conductive semiconductor layer 131 and the second conductive semiconductor layer 133, and the electron blocking may be performed between the active layer 132 and the second conductive semiconductor layer 133. The layer 140 may be interposed.

The first conductive semiconductor layer 131 is a semiconductor material having a composition formula of Al _x In _y Ga _(1-xy) N (0 = x = 1, 0 = y = 1, 0 = x + y = 1) For example, one or more of GaN, InN, AlN, InGaN, AlGaN, InAlGaN, and AlInN. And may be formed using another Group 5 element instead of N. For example, at least one of AlGaAs, InGaAs, AlInGaAs, GaP, AlGaP, InGaP, AlInGaP, and InP. In addition, when the first conductivity-type semiconductor layer 131 is an n-type semiconductor layer, for example, the n-type impurity may include Si, Ge, Sn, Se, Te, or the like. Hereinafter, the first conductive semiconductor layer will be described as an example of an n-type semiconductor layer.

The active layer 132 may be formed on the first conductive semiconductor layer 131. The active layer 132 is a region where electrons and holes are recombined. The active layer 132 transitions to a low energy level as the electrons and holes recombine, and may generate light having a corresponding wavelength.

The active layer 132 includes 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) And may be formed of a single quantum well structure or a multi quantum well (MQW) structure.

Therefore, more electrons are collected at the lower energy level of the quantum well layer, and as a result, the probability of recombination of electrons and holes can be increased, thereby improving the light emitting effect. It may also include a quantum wire structure or a quantum dot structure.

The second conductivity type semiconductor layer 133 may be formed on the active layer 132. The second conductivity type semiconductor layer 133 may be a p-type semiconductor layer, and may inject holes into the active layer 132. For example, the p-type semiconductor layer 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, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN and the like, and may be doped with p-type impurities such as Mg, Zn, Ca, Sr and Ba. Hereinafter, the second conductive semiconductor layer 133 is described as an example of a p-type conductive semiconductor layer.

An electron blocking layer 140 may be formed between the active layer 132 and the second conductive semiconductor layer 133. The electron blocking layer 140 is formed between the active layer 132 and the second conductivity type semiconductor layer 133, and the electrons having a higher mobility than the holes are overflowed through the active layer 132. It functions to block. To this end, the energy bandgap is made of a material higher than that of the active layer 132, and the energy bandgap can be appropriately adjusted by the content of aluminum (Al) or indium (In).

The electron blocking layer 140 may block the overflow of electrons to increase the recombination probability of electrons and holes in the active layer 132, thereby improving luminous efficiency.

Referring to FIG. 2, the electron blocking layer 140 may sequentially stack the first layer 141, the second layer 142, and the third layer 143, and may vary Ga content. Multi-layer structure of the electron blocking layer 140 of 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) It can be made, and the p-type impurities can be doped.

In addition, the electron blocking layer may be formed to a total thickness of 90nm to 500nm in consideration of the effect of the electron blocking and the overall quality degradation of the light emitting device, the first layer 141, the second layer 142 and the third Each thickness of layer 143 may be formed from 30 nm to 150 nm.

The first layer 141 is a layer in contact with the active layer 132 and is an initial growth layer. The first layer 141 may have a higher content of aluminum (Al) to increase the energy band gap than the active layer 132. Since the bonding force between aluminum (Al) and gallium (Ga) is large, the first layer 141 may be difficult to dop the p-type impurities such as magnesium (Mg) and zinc (Zn).

Therefore, when the gallium (Ga) content is linearly increased relative to aluminum (Al), the doping efficiency of the p-type impurity may be improved.

The second layer 142 may linearly reduce the gallium (Ga) content. Reducing the gallium (Ga) content increases the aluminum (Al) content relatively, thereby increasing the energy bandgap. When the energy bandgap increases, electrons injected from the first conductivity type semiconductor layer 131 can be effectively prevented from overflowing the active layer 132 to the second conductivity type semiconductor layer 133 and thus the second layer. 142 may maximize the effect of the electron blocking layer 140.

The third layer 143 may linearly increase the gallium (Ga) content. The third layer 143 is a layer in contact with the second conductivity type semiconductor layer 133, so that an energy band gap must be small to prevent blocking of holes injected from the second conductivity type semiconductor layer 133. Therefore, the aluminum (Al) content may be relatively small in order to reduce the energy band gap.

At the interface between the third layer 143 and the second conductivity-type semiconductor layer 133, aluminum (Al) is relatively small, so that the p-type impurity doping occurs well, and the excessively doped p-type impurity is formed in the third layer 143. At the interface between the second conductive semiconductor layer 133 and the strain due to the lattice constant difference occurs. As a result, the p-type impurities aggregate. When the p-type impurities are agglomerated, a defective structure is generated between the third layer 143 and the second conductive semiconductor layer 133, thereby degrading the overall performance and efficiency of the light emitting device.

Accordingly, when the gallium (Ga) content of the third layer 143 is linearly increased in the stacked direction, the p-type impurity doping efficiency may be reduced, and over-doping of the p-type impurity may be prevented.

In addition, as described above, since the electron blocking layer 140 is formed in a multilayer structure having different energy band gaps, the effect of spreading holes due to the difference in energy band gaps of the layers of the multilayer structure may be obtained. The probability of injecting holes into the active layer 132 from the two-conducting semiconductor layer 133 may be increased.

Meanwhile, the first conductive semiconductor layer 131, the active layer 132, the electron blocking layer 140, and the second conductive semiconductor layer 133 may be formed of metal organic chemical vapor deposition (MOCVD), Chemical Vapor Deposition (CVD), Plasma-Enhanced Chemical Vapor Deposition (PECVD), Molecular Beam Epitaxy (MBE), Hydride Vapor Phase Epitaxy (HVPE), Sputtering It may be formed using a method such as (Sputtering), but is not limited thereto.

Referring back to FIG. 1, a first electrode 160 may be formed on the first conductive semiconductor layer 131, and a second electrode 150 may be formed on the second conductive semiconductor layer 133. .

In this case, mesa etching may be performed from the second conductive semiconductor layer 133 to a part of the first conductive semiconductor layer 131 to secure a space for forming the first electrode 160. The first electrode 160 may be formed in an etched and exposed area of the surface of the first conductive semiconductor layer 131.

In addition, the first electrode 160 and the second electrode 150 may be formed of a conductive material, for example, indium (In), cobalt (Co), silicon (Si), germanium (Ge), and gold (Au). ), Palladium (Pd), platinum (Pt), ruthenium (Ru), rhenium (Re), magnesium (Mg), zinc (Zn), hafnium (Hf), tantalum (Ta), rhodium (Rh), iridium (Ir) ), Tungsten (W), titanium (Ti), silver (Ag), chromium (Cr), molybdenum (Mo), niobium (Nb), aluminum (Al), nickel (Ni) and copper (Cu) It may be formed or formed of two or more alloys, it may be formed by stacking two or more different materials.

3 is a cross-sectional view showing a cross section of a vertical light emitting device according to the embodiment.

Referring to FIG. 3, the vertical light emitting device 200 according to the embodiment may include a support substrate 210, a first conductivity type semiconductor layer 231, an active layer 232, an electron blocking layer 240, and a second conductivity type. The light emitting structure 230 including the semiconductor layer 233, the second electrode layer 260, the conductive layer 270, and the first electrode 250 may be included. Compared with the embodiment of FIG. 1, there is a difference that the support substrate 210, the conductive layer 270, and the second electrode layer 240 are further included. Description of the same components will be omitted below.

Support substrate 210 may be formed of a conductive material, for example, gold (Au), nickel (Ni), tungsten (W), molybdenum (Mo), copper (Cu), aluminum (Al), tantalum ( Ta), silver (Ag), platinum (Pt), chromium (Cr), Si, Ge, GaAs, ZnO, GaN, Ga ₂ O ₃ or SiC, SiGe, CuW, or any one of two or more alloys It may be formed by stacking two or more different materials.

The support substrate 210 may facilitate the emission of heat generated from the light emitting device 200 to improve the thermal stability of the light emitting device 200.

A bonding layer (not shown) may be formed on the support substrate 210 to couple the support substrate 210 and the conductive layer 270 to each other. The bonding layer (not shown) is, for example, a group consisting of gold (Au), tin (Sn), indium (In), silver (Ag), nickel (Ni), niobium (Nb), and copper (Cu). It may be formed of a material selected from or alloys thereof.

The conductive layer 270 is a material selected from the group consisting of nickel (Ni-nickel), platinum (Pt), titanium (Ti), tungsten (W), vanadium (V), iron (Fe), and molybdenum (Mo). Or they may be made of an alloy optionally included.

Conductive layer 270 may be formed using a sputtering deposition method. When using the sputter deposition method, when ionized atoms are accelerated by an electric field and collide with the source material of the conductive layer 270, atoms of the source material are ejected and deposited. In addition, according to the embodiment, an electrochemical metal deposition method, a bonding method using a eutectic metal, or the like may be used. In some embodiments, the conductive layer 270 may be formed of a plurality of layers.

The conductive layer 270 has an effect of minimizing mechanical damage (breaking or peeling, etc.) that may occur in the manufacturing process of the light emitting device.

In addition, the conductive layer 270 has an effect of preventing the metal material constituting the support substrate 210 or the bonding layer (not shown) from being diffused into the light emitting structure 230.

Referring again to FIG. 3, the second electrode layer 260 may selectively use a metal and a light-transmitting conductive layer to provide power to the light-emitting structure 230. The second electrode layer 260 may be formed including a conductive material. For example, nickel (Ni), platinum (Pt), ruthenium (Ru), iridium (Ir), rhodium (Rh), tantalum (Ta), molybdenum (Mo), titanium (Ti), silver (Ag), tungsten (W), copper (Cu), chromium (Cr), palladium (Pd), vanadium (V), cobalt (Co), niobium (Nb), zirconium (Zr), indium tin oxide (ITO), Aluminum zinc oxide (AZO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), indium gallium (IGTO) tin oxide), antimony tin oxide (ATO), gallium zinc oxide (GZO), IrO _x , RuO _x , RuO _x / ITO, Ni / IrO _x / Au, or Ni / IrO _x / Au / ITO Can be. However, it is not limited thereto.

In addition, the second electrode layer 260 may be formed as a single layer or multiple layers of a reflective electrode material having ohmic characteristics.

The second electrode layer 260 is a structure of an ohmic layer 261 / reflection layer 262 / bonding layer (not shown), a laminated structure of the ohmic layer 261 / reflection layer 262, or a reflective layer (including ohmic) 262. ) / Bonding layer (not shown), but is not limited thereto.

The ohmic layer 261 is in ohmic contact with a lower surface of the light emitting structure (eg, the second conductivity-type semiconductor layer 233), and may be formed in a layer or a plurality of patterns. The ohmic layer 261 may selectively use a light transmissive conductive layer and a metal. For example, indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), and indium aluminum zinc (AZO) oxide), IGZO (indium gallium zinc oxide), IGTO (indium gallium tin oxide), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IZON (IZO Nitride), AGZO (Al- Ga ZnO), IGZO (In-Ga ZnO), ZnO, IrOx, RuOx, NiO, RuOx / ITO, Ni / IrOx / Au, and Ni / IrOx / Au / ITO, Ag, Ni, Cr, Ti, Al, Rh , Pd, Ir, Sn, In, Ru, Mg, Zn, Pt, Au, can be formed including at least one of Hf, and is not limited to these materials. The ohmic layer 261 may be formed by sputtering or electron beam deposition. The reflective layer 262 reflects the light toward the upper direction of the light emitting device 200 when some of the light generated from the active layer 232 of the light emitting structure 230 is directed toward the support substrate 210. It is possible to improve the light extraction efficiency of 200).

The reflective layer 262 is made of a metal layer including aluminum (Al), silver (Ag), nickel (Ni), platinum (Pt), rhodium (Rh), or an alloy containing Al, Ag, Pt, or Rh, It may be formed in multiple layers using the metal material and light transmitting conductive materials such as IZO, IZTO, IAZO, IGZO, IGTO, AZO, and ATO. In addition, the reflective layer 262 may be laminated with IZO / Ni, AZO / Ag, IZO / Ag / Ni, AZO / Ag / Ni, or the like. In addition, when the reflective layer 262 is formed of a material in ohmic contact with the light emitting structure (eg, the second conductivity-type semiconductor layer 233), the ohmic layer 261 may not be formed separately, but is not limited thereto.

Although the reflective layer 262 and the ohmic layer 261 are described as having the same width and length, at least one of the width and the length may be different and the present invention is not limited thereto.

The bonding layer (not shown) may include a barrier metal or a bonding metal such as titanium (Ti), gold (Au), tin (Sn), nickel (Ni), chromium (Cr) ), Indium (In), bismuth (Bi), copper (Cu), silver (Ag), or tantalum (Ta).

4 to 9 are views showing a manufacturing process of the light emitting device according to the embodiment.

Referring to FIG. 4, first, a buffer layer 120, a first conductive semiconductor layer 131, and an active layer 132 are sequentially formed on the growth substrate 110.

The growth substrate 110 may be selected from the group consisting of sapphire substrate (Al ₂ O ₃ ), GaN, SiC, ZnO, Si, GaP, InP, and GaAs.

The buffer layer 120 may be formed of a combination of Group 3 and Group 5 elements, or may be formed of any one of GaN, InN, AlN, InGaN, AlGaN, InAlGaN, and AlInN, and dopants may be doped.

An undoped semiconductor layer may be formed on the growth substrate 110 or the buffer layer 120, and either or both of the buffer layer 120 and the undoped conductive semiconductor layer (not shown) are formed. It may or may not be formed and is not limited to this structure.

The first conductive semiconductor layer 131 and the active layer 132 may be sequentially formed on the growth substrate 110.

The first conductive semiconductor layer 131 injects silane gas (SiH4) containing N-type impurities such as trimethyl gallium gas (TMGa), ammonia gas (NH3), nitrogen gas (N2), and silicon (Si) into the chamber. Can be formed.

The active layer 132 may be grown in a nitrogen atmosphere while injecting trimethyl gallium gas (TMGa) and trimethyl indium gas (TMIn), and a single quantum well structure, a multi quantum well structure (MQW), and a quantum line It may be formed of at least one of a wire structure or a quantum dot structure.

Referring to FIG. 5, the electron blocking layer 140 may be formed on the active layer 132. The electron blocking layer 140 may be formed by sequentially growing the first layer 141, the second layer 142, and the third layer 143.

The electron blocking layer 140 may be grown by appropriately adjusting the injection amount of gallium (Ga), aluminum (Al), and p-type impurities, wherein the p-type impurity is described in detail with reference to FIG. 6 using magnesium (Mg) as an example. do.

6 shows the relative growth rates (injection amount per hour) of gallium (Ga), aluminum (Al), and magnesium (Mg) when the first layer 141, the second layer 142, and the third layer 143 are grown. The graph shown.

Referring to FIG. 6, in the case of the first layer 141, the growth rate of gallium (Ga) may be linearly increased, and the amounts of aluminum (Al) and magnesium (Mg) may be maintained to be relatively constant.

As described above, when the first layer 141 is grown, the amount of gallium (Ga) injected may increase, thereby increasing the doping efficiency of magnesium (Mg).

In the case of the second layer 142, the growth rate of gallium (Ga) may be linearly reduced, and the amount of aluminum (Al) and magnesium (Mg) may be maintained to be relatively constant.

As described above, when the second layer 142 is grown by reducing the injection amount of gallium (Ga), the content of aluminum (Al) is relatively increased, thereby increasing the energy band gap, thereby blocking the electron blocking layer 140. ) Can maximize the effect.

In the case of the third layer 143, the growth rate of gallium (Ga) is linearly increased, and the amount of aluminum (Al) and magnesium (Mg) may be maintained to be relatively constant to grow.

As described above, when the growth amount of gallium (Ga) is increased, the doping efficiency of magnesium (Mg) may be decreased, and the amount of magnesium (Mg) to be doped may be reduced, so that the third layer 143 and the third layer ( Aggregation of magnesium (Mg) at the interface of the second conductivity-type semiconductor layer 133 to be formed on 143 may be prevented.

Referring to FIG. 5 again, a second conductivity type semiconductor layer 133 may be formed on the third layer 143.

The second conductive semiconductor layer 133 has trimethyl gallium gas (TMGa), trimethyl aluminum gas (TMAl), bicetyl cyclopentadienyl magnesium (EtCp2Mg) {Mg ( C2H5C5H4) 2} and the like can be grown, but is not limited thereto.

Then, the manufacturing process of the horizontal light emitting device and the vertical light emitting device is different.

7 is a view showing a manufacturing process of the horizontal light emitting device after the process shown in FIG.

Referring to FIG. 7, Mesa is etched from the second conductive semiconductor layer 133 to a portion of the first conductive semiconductor layer 131 by a reactive ion etching (RIE) method. For example, when an insulating substrate such as a sapphire substrate is used, electrodes can not be formed under the substrate. Therefore, mesa etching is performed from the second conductivity type semiconductor layer 133 to a portion of the first conductivity type semiconductor layer 131 , It is possible to secure a space in which electrodes can be formed. Accordingly, the first electrode 160 may be formed in an etched and exposed area of the surface of the first conductivity type semiconductor layer 131.

The second electrode 150 may be formed on the second conductive semiconductor layer 133.

8 and 9 are views showing a manufacturing process of the vertical light emitting device after the process shown in FIG.

Referring to FIG. 8, a second electrode layer 260 may be formed on the second conductive semiconductor layer 133, and the support substrate 210 on which the conductive layer 270 is disposed may be bonded and bonded. In this case, the growth substrate 110 disposed on the first conductivity type semiconductor layer 131 may be separated.

In this case, the growth substrate 210 may be removed by a physical or / and chemical method, and the physical method may be removed by, for example, a laser lift off (LLO) method.

Meanwhile, the buffer layer 120 may be removed after the growth substrate 110 is removed. In this case, the buffer layer 120 may be removed through a dry or wet etching method or a polishing process.

In addition, although not shown, the outer area of the light emitting structure 230 may be etched to have an inclination, and a passivation (not shown) may be formed on a part or the entire area of the outer circumferential surface of the light emitting structure 230. Passivation (not shown) may be formed of an insulating material.

The first electrode 260 may be formed on the surface of the first conductive semiconductor layer 231.

At least one process in the process sequence shown in FIGS. 4 to 9 may be reversed, but the embodiment is not limited thereto.

10 is a cross-sectional view illustrating a light emitting device package including the light emitting device according to the embodiment.

10, the light emitting device package 300 according to the embodiment includes a body 310 having a cavity, a light source 320 mounted on a cavity of the body 310, and an encapsulant 350 filled in the cavity 310 can do.

The body 310 is made of a resin material such as polyphthalamide (PPA), silicon (Si), aluminum (Al), aluminum nitride (AlN), photosensitive glass (PSG), polyamide 9T (PA9T) ), Neo geotactic polystyrene (SPS), a metal material, sapphire (Al2O3), beryllium oxide (BeO), a printed circuit board (PCB, Printed Circuit Board), it may be formed of at least one. The body 310 may be formed by injection molding, etching, or the like, but is not limited thereto.

The light source unit 320 may be mounted on the bottom surface of the body 310. For example, the light source unit 320 may be any one of the light emitting devices illustrated and described with reference to FIGS. 1 to 3. The light emitting device may be, for example, a colored light emitting device emitting light of red, green, blue, white, or the like, or an ultraviolet (UV) light emitting device emitting ultraviolet light, but is not limited thereto. In addition, one or more light emitting elements can be mounted.

The body 310 may include a first electrode 330 and a second electrode 340. The first electrode 330 and the second electrode 340 may be electrically connected to the light source 320 to supply power to the light source 320.

In addition, the first electrode 330 and the second electrode 340 are electrically separated from each other, and may reflect light generated from the light source unit 320 to increase light efficiency, and also generate heat generated from the light source unit 320. Can be discharged to the outside.

10 illustrates that both the first electrode 330 and the second electrode 340 are bonded to the light source unit 320 by the wire 360, but the present invention is not limited thereto. Any one of the electrode 330 and the second electrode 340 may be bonded to the light source unit 320 by the wire 360, or may be electrically connected to the light source unit 320 without the wire 360 by a flip chip method. have.

The first electrode 330 and the second electrode 340 are made of a metal material, for example, titanium (Ti), copper (Cu), nickel (Ni), gold (Au), chromium (Cr), and tantalum ( Ta, platinum (Pt), tin (Sn), silver (Ag), phosphorus (P), aluminum (Al), indium (In), palladium (Pd), cobalt (Co), silicon (Si), germanium ( Ge), hafnium (Hf), ruthenium (Ru), iron (Fe) may include one or more materials or alloys. In addition, the first electrode 330 and the second electrode 340 may be formed to have a single layer or a multilayer structure, but is not limited thereto.

The encapsulant 350 may be filled in the cavity, and may include a phosphor (not shown). The encapsulant 350 may be formed of transparent silicone, epoxy, and other resin materials, and may be formed by filling in a cavity and then ultraviolet or thermal curing.

The phosphor (not shown) may be selected according to the wavelength of the light emitted from the light source unit 320 so that the light emitting device package 300 may implement white light.

The phosphor (not shown) included in the encapsulant 350 may be a blue light emitting phosphor, a cyan light emitting phosphor, a green light emitting phosphor, a yellow green light emitting phosphor, a yellow light emitting phosphor, or a yellow red light emitting phosphor according to a wavelength of light emitted from the light source unit 320. One of orange luminescent phosphor, and red luminescent phosphor can be applied.

That is, the phosphor (not shown) may be excited by the light having the first light emitted from the light source unit 320 to generate the second light. For example, when the light source unit 320 is a blue light emitting diode and the phosphor (not shown) is a yellow phosphor, the yellow phosphor may be excited by blue light to emit yellow light, and blue light and blue generated from the blue light emitting diode As the yellow light generated by being excited by the light is mixed, the light emitting device package 300 may provide white light.

FIG. 11A is a perspective view illustrating a lighting device including a light emitting device module according to an embodiment, and FIG. 11B is a cross-sectional view illustrating a C-C 'cross section of the lighting device of FIG. 11A.

11B is a sectional view of the lighting apparatus 400 of FIG. 11A cut in the longitudinal direction Z and the height direction X and viewed in the horizontal direction Y. FIG.

11A and 11B, the lighting apparatus 400 may include a body 410, a cover 430 to be coupled to the body 410, and a finishing cap 450 positioned at both ends of the body 410 have.

The lower surface of the body 410 is fastened to the light emitting device module 440, the body 410 is conductive and so that the heat generated from the light emitting device package 444 can be discharged to the outside through the upper surface of the body 410 The heat dissipation effect may be formed of an excellent metal material, but is not limited thereto.

In particular, the light emitting device module 440 may include a sealing part (not shown) surrounding the light emitting device package 444 to prevent penetration of foreign matters, thereby improving reliability, and also providing reliable lighting apparatus 400. Implementation of.

The light emitting device package 444 may be mounted on the substrate 442 in multiple colors and in multiple rows to form a module. The light emitting device package 444 may be mounted at the same interval or may be mounted at various separation distances as necessary to adjust brightness. As the substrate 442, a metal core PCB (MCPCB) or a PCB made of FR4 may be used.

The cover 430 may be formed in a circular shape to surround the lower surface of the body 410, but is not limited thereto.

The cover 430 protects the light emitting device module 440 from the outside and the like. In addition, the cover 430 may include diffusing particles to prevent glare of the light generated from the light emitting device package 444 and to uniformly emit light to the outside, and may also include at least one of an inner surface and an outer surface of the cover 430. A prism pattern or the like may be formed on either side. In addition, a phosphor may be applied to at least one of an inner surface and an outer surface of the cover 430.

On the other hand, since the light generated from the light emitting device package 444 is emitted to the outside through the cover 430, the cover 430 should be excellent in the light transmittance, sufficient to withstand the heat generated in the light emitting device package 444 The cover 430 is formed of a material including polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA), or the like. It is desirable to be.

Closing cap 450 is located at both ends of the body 410 may be used for sealing the power supply (not shown). In addition, the closing cap 450 is a power pin 452 is formed, the lighting device 400 according to the embodiment can be used immediately without a separate device to the terminal from which the existing fluorescent lamps are removed.

12 and 13 are exploded perspective views of a liquid crystal display device including an optical sheet according to an embodiment.

12, the liquid crystal display device 500 may include a liquid crystal display panel 510 and a backlight unit 570 for providing light to the liquid crystal display panel 510 in an edge-light manner.

The liquid crystal display panel 510 may display an image by using light provided from the backlight unit 570. The liquid crystal display panel 510 may include a color filter substrate 512 and a thin film transistor substrate 514 facing each other with a liquid crystal interposed therebetween.

The color filter substrate 512 may implement colors of an image displayed through the liquid crystal display panel 510.

The thin film transistor substrate 514 is electrically connected to the printed circuit board 518 on which a plurality of circuit components are mounted through the driving film 517. The thin film transistor substrate 514 may apply a driving voltage provided from the printed circuit board 518 to the liquid crystal in response to a driving signal provided from the printed circuit board 518.

The thin film transistor substrate 514 may include a thin film transistor and a pixel electrode formed of a thin film on another substrate of a transparent material such as glass or plastic.

The backlight unit 570 may convert the light provided from the light emitting device module 520, the light emitting device module 520 into a surface light source, and provide the light guide plate 530 to the liquid crystal display panel 510. Reflective sheet for reflecting the light emitted from the rear of the light guide plate 530 and the plurality of films 550, 566, 564 to uniform the luminance distribution of the light provided from the 530 and improve the vertical incidence ( 540.

The light emitting device module 520 may include a PCB substrate 522 so that a plurality of light emitting device packages 524 and a plurality of light emitting device packages 524 may be mounted to form a module.

In particular, the light emitting device module 520 may include a sealing part (not shown) surrounding the light emitting device package 524 to prevent foreign matter from penetrating, thereby improving reliability, and also providing reliable backlight unit 570. Implementation of.

Meanwhile, the backlight unit 570 includes a diffusion film 566 for diffusing light incident from the light guide plate 530 toward the liquid crystal display panel 510, and a prism film 550 for condensing the diffused light to improve vertical incidence. ), And may include a protective film 564 to protect the prism film 550.

13 is an exploded perspective view of a liquid crystal display device including an optical sheet according to an embodiment. However, the parts shown and described in Fig. 12 are not repeatedly described in detail.

13, the liquid crystal display 600 may include a liquid crystal display panel 610 and a backlight unit 670 for providing light to the liquid crystal display panel 610 in a direct-down manner.

Since the liquid crystal display panel 610 is the same as that described with reference to FIG. 10, a detailed description thereof will be omitted.

The backlight unit 670 may include a plurality of light emitting device modules 623, a reflective sheet 624, a lower chassis 630 in which the light emitting device modules 623 and the reflective sheet 624 are accommodated, and an upper portion of the light emitting device module 623. It may include a diffusion plate 640 and a plurality of optical film 660 disposed in the.

LED Module 623 A plurality of light emitting device packages 622 and a plurality of light emitting device packages 622 may be mounted to include a PCB substrate 621 to form a module.

In particular, the light emitting device module 623 may include a sealing part (not shown) surrounding the light emitting device package 622 to prevent foreign matter from penetrating, thereby improving reliability, and also providing reliable backlight unit 670. Implementation of.

The reflective sheet 624 reflects the light generated from the light emitting device package 622 in the direction in which the liquid crystal display panel 610 is positioned to improve light utilization efficiency.

On the other hand, the light generated from the light emitting device module 623 is incident on the diffusion plate 640, the optical film 660 is disposed on the diffusion plate 640. The optical film 660 includes a diffusion film 666, a prism film 650, and a protective film 664.

Although the above has been illustrated and described with respect to preferred embodiments of the present invention, the present invention is not limited to the specific embodiments described above, but in the art to which the invention pertains without departing from the spirit of the invention as claimed in the claims. Various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

110: growth substrate 120: buffer layer
131: first conductivity type semiconductor layer 132: active layer
133: second conductivity type semiconductor layer 140: electron blocking layer
150: second electrode 160: first electrode

Claims

A first conductive semiconductor layer;
An active layer disposed on the first conductivity type semiconductor layer;
An electron blocking layer disposed on the active layer, in which a first layer, a second layer, and a third layer including Ga are sequentially disposed; And
A second conductive semiconductor layer disposed on the electron blocking layer;
Along the stacking direction in which the first layer, the second layer and the third layer are sequentially arranged, the amount of the Ga increases in the first layer and the third layer, and the amount of the Ga increases in the second layer. Decreasing light emitting element.

The method of claim 1,
The light emitting device of claim 1, wherein the first layer and the third layer linearly increase the amount of Ga, and the second layer linearly decrease the amount of Ga.

The method of claim 1,
The electron blocking layer is a light emitting device containing p-type impurities.

The method of claim 3,
The p-type impurity is Mg or Zn light emitting device.

The method of claim 3,
Wherein the amount of the p-type impurity is proportional to the amount of Ga.

The method of claim 1,
The electron blocking layer is made of a semiconductor material having a composition formula of In _x Al _y Ga ₁ _- _x N (0≤x≤1, 0≤y≤1, 0≤x + y≤1).

The method of claim 1,
The size of the energy bandgap of the electron blocking layer is inversely proportional to the amount of Ga.

The method of claim 1,
Along the stacking direction, the first layer and the third layer has a linear energy bandgap decreases linearly, the second layer has a linear energy bandgap increases linearly.

The method of claim 1,
The thickness of the electron blocking layer is 90nm to 500nm, the thickness of each of the first layer, the second layer and the third layer is a light emitting device of 30nm to 150nm.