KR20130049316A - Light emitting device - Google Patents

Light emitting device Download PDF

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Publication number
KR20130049316A
KR20130049316A KR1020110114263A KR20110114263A KR20130049316A KR 20130049316 A KR20130049316 A KR 20130049316A KR 1020110114263 A KR1020110114263 A KR 1020110114263A KR 20110114263 A KR20110114263 A KR 20110114263A KR 20130049316 A KR20130049316 A KR 20130049316A
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Prior art keywords
light emitting
emitting device
layer
semiconductor layer
conductive semiconductor
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KR1020110114263A
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Korean (ko)
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김재훈
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엘지이노텍 주식회사
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Publication of KR20130049316A publication Critical patent/KR20130049316A/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/20—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a particular shape, e.g. curved or truncated substrate
    • H01L33/22—Roughened surfaces, e.g. at the interface between epitaxial layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/44—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the coatings, e.g. passivation layer or anti-reflective coating
    • H01L33/46—Reflective coating, e.g. dielectric Bragg reflector

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  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Led Devices (AREA)

Abstract

The light emitting device of the embodiment includes 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, each of which is grown in a nonpolar or semipolar direction. Polarized light including a light emitting structure and a surface grating reflector disposed on the light emitting structure, and having a wavelength corresponding to the structure of the surface grating reflector is emitted from the light emitting element.

Description

[0001]

An embodiment relates to a light emitting element.

Light emitting devices such as light emitting diodes or laser diodes using semiconductors of Group 3-5 or 2-6 compound semiconductor materials of semiconductors have various colors such as red, green, blue, and ultraviolet rays due to the development of thin film growth technology and device materials. By using fluorescent materials or by combining colors, efficient white light can be realized, and low power consumption, semi-permanent life, fast response speed, safety and environmental friendliness compared to conventional light sources such as fluorescent and incandescent lamps can be realized. Has an advantage.

Therefore, it is possible to replace the LED backlight, fluorescent lamp or incandescent bulb which replaces the cold cathode fluorescent lamp (CCFL) constituting the transmission module of the optical communication means, the backlight of the liquid crystal display (LCD). Its application is expanding to white light emitting diode lighting devices, automobile headlights and signals, and the like.

Republic of Korea Patent Application Publication No. 10-2011-0041270

OPTICS EXPRESS 22535-22542, Vol. 17, No. 25, 7 December 2009, "Polarization-dependent GaN surface grating reflector for short wavelength applications", Joonhee Lee et al.

The embodiment provides a light emitting device capable of emitting polarized light having a desired wavelength.

The light emitting device of the embodiment includes an active layer disposed between the first conductive semiconductor layer, the second conductive semiconductor layer, and the first conductive semiconductor layer and the second conductive semiconductor layer, each of which is grown in a nonpolar or semipolar direction. Light emitting structure comprising a; And a surface grating reflector disposed on the light emitting structure, wherein polarized light having a wavelength corresponding to the structure of the surface grating reflector is emitted from the light emitting element.

The polarized light is emitted in a direction perpendicular to the M-plane, a-plane or the R-plane. The surface grating reflector has an uneven structure.

The surface grating reflector is made of the same material or a different material from that of the first conductivity type semiconductor layer.

The light emitting device may further include: a first electrode layer formed on the light emitting structure and in contact with the first conductive semiconductor layer; And a second electrode layer formed under the light emitting structure and in contact with the second conductive semiconductor layer. Alternatively, the light emitting device may include a first electrode layer; And a second electrode layer formed under the light emitting structure and in contact with the second conductive semiconductor layer, wherein the first electrode layer penetrates through the second electrode layer, the second conductive semiconductor layer, and the active layer. In contact with the first conductive semiconductor layer is formed below the second electrode layer.

The uneven structure may be arranged regularly, wherein at least one of the period of the uneven structure, the angle at which the side edge of the convex portion is inclined in the uneven structure, the peeling factor to the uneven structure, or the height of the convex portion is the wavelength of the polarized light. Has a value corresponding to

The wavelength of the light emitted from the active layer may be smaller than the period.

Also, when the height is 100 nm to 250 nm, and the period is 250 nm to 450 nm, the wavelength is 370 nm to 500 nm. Alternatively, when the height is 450 nm to 700 nm and the period is 150 nm to 450 nm, the wavelength is 370 nm to 500 nm. Alternatively, when the height is 114 nm, the period is 450 nm, and the filling factor is 0.3 to 0.7, the wavelength is 450 nm. Alternatively, when the height is 114 nm, the peeling factor is 0.4, and the angle is 0 to 20 °, the wavelength is 450 nm.

The light emitting device according to the embodiment may emit polarized light having a desired wavelength.

1 is a cross-sectional view of a light emitting device according to an embodiment.
2 is a diagram showing a structure of sapphire crystal.
3 is an enlarged cross-sectional view of the surface grating reflector illustrated in FIG. 1.
4A to 4C are diagrams showing diffraction effect spectra.
5A to 5C are graphs showing reflectance according to period and height for each wavelength.
6 is a graph showing the relationship between the wavelengths of the filling factors when the height is 114 nm and the period is 450 nm.
FIG. 7 is a graph showing the relationship between inclined angle wavelengths when the height is 114 nm and the filling factor is 0.4.
8 is a cross-sectional view of a light emitting device according to another embodiment.
9 is a diagram illustrating an application example of a light emitting device according to an embodiment.
10A to 10E are views illustrating an embodiment of a manufacturing method of the light emitting device shown in FIG. 1.
11 is a view showing an embodiment of a light emitting device package.
12 is a diagram illustrating an embodiment of a head lamp including a light emitting device package.
13 is a view illustrating an embodiment of a display device including a light emitting device package.

Hereinafter, embodiments will be described with reference to the accompanying drawings.

In the description of the embodiment according to the present invention, in the case of being described as being formed on the "upper" or "on or under" of each element, on or under includes both elements being directly contacted with each other or one or more other elements being indirectly formed between the two elements. In addition, when expressed as "up" or "on (under)", it may include not only an upward direction but also a downward direction based on one element.

The thickness and size of each layer in the drawings are exaggerated, omitted, or schematically shown for convenience and clarity of explanation. In addition, the size of each component does not necessarily reflect the actual size.

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

The light emitting device 100 according to the embodiment includes a bonding layer 120, a reflective layer 134, an ohmic layer 132, a light emitting structure 140, and a surface grating reflector on a conductive support substrate (metal support) 110. (SGR: Surface Grating Reflector) 150 and the first electrode layer 160.

The conductive support substrate 110 formed under the light emitting structure 140 may serve as a second electrode layer together with the ohmic layer 132 and the reflective layer 134, and thus a metal having excellent electrical conductivity may be used, and the light emitting device may be used. Metals with high thermal conductivity can be used because they must be able to dissipate heat generated during operation.

For example, the conductive support substrate 110 may be made of a material selected from the group consisting of molybdenum (Mo), silicon (Si), tungsten (W), copper (Cu), and aluminum (Al) or alloys thereof. Also, gold (Au), copper alloy (Cu Alloy), nickel (Ni), copper-tungsten (Cu-W), carrier wafers (e.g. GaN, Si, Ge, GaAs, ZnO, SiGe, SiC, SiGe) , Ga 2 O 3, etc.) may be optionally included.

In addition, the conductive support substrate 110 may have a mechanical strength enough to separate well into separate chips through a scribing process and a breaking process without causing warping of the entire nitride semiconductor. .

The bonding layer 120 corresponds to an adhesion layer coupling the reflective layer 134 and the conductive support substrate 110. However, the reflective layer 134 may also function as a bonding layer. For example, the bonding layer 120 is made of gold (Au), tin (Sn), indium (In), aluminum (Al), silicon (Si), silver (Ag), nickel (Ni), and copper (Cu). It may be formed of a material selected from the group consisting of or alloys thereof.

The reflective layer 134 may be about 2500 angs thick. For example, the reflective layer 134 may include a metal layer including aluminum (Al), silver (Ag), nickel (Ni), platinum (Pt), rhodium (Rh), or an alloy containing Al, Ag, Pt, or Rh. Can be made. Aluminum or silver may effectively reflect light generated from the active layer 144 to greatly improve the light extraction efficiency of the light emitting device.

Since the light emitting structure 140, in particular, the second conductivity type semiconductor layer 146 has a low impurity doping concentration and a high contact resistance, and thus may have poor ohmic characteristics, the light emitting structure 140 may be transparent to the ohmic layer 132 to improve such ohmic characteristics. Electrodes and the like can be formed.

The ohmic layer 132 may be about 200 angstroms thick. For example, the ohmic layer 132 may include indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), and IGTO (IGTO). indium gallium tin oxide (AZO), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IZO (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, It may be formed including at least one of Zn, Pt, Au, Hf, and is not limited to these materials.

The light emitting structure 140 includes a first conductive semiconductor layer 142, an active layer 144, and a second conductive semiconductor layer 146. Here, the second conductive semiconductor layer 146 is formed on the ohmic layer 132, and the active layer 144 is formed between the second conductive semiconductor layer 146 and the first conductive semiconductor layer 142. To emit light.

The first conductivity type semiconductor layer 142 may be implemented as a group III-V compound semiconductor doped with a first conductivity type dopant, and when the first conductivity type semiconductor layer 142 is an N-type semiconductor layer, The conductive dopant is an N-type dopant and may include Si, Ge, Sn, Se, Te, but is not limited thereto.

The first conductivity type semiconductor layer 142 may be formed of a semiconductor compound. It may be implemented as a compound semiconductor, such as Group 3-5, Group 2-6, and the first conductivity type dopant may be doped. For example, 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). The first conductive semiconductor layer 142 may be formed of any one or more of GaN, InN, AlN, InGaN, AlGaN, InAlGaN, AlInN, AlGaAs, InGaAs, AlInGaAs, GaP, AlGaP, InGaP, AlInGaP, InP.

In the active layer 144, electrons (or holes) injected through the first conductivity-type semiconductor layer 142 and holes (or electrons) injected through the second conductivity-type semiconductor layer 146 meet each other to form an active layer ( 144 is a layer that emits light with energy determined by the energy bands inherent in the material making up it.

The active layer 144 may include a single well structure, a multi well structure, a single quantum well structure, a multi quantum well structure (MQW), a quantum-wire structure, or a quantum dot. ) And at least one of the structures. For example, the active layer 144 may be injected with trimethyl gallium gas (TMGa), ammonia gas (NH 3 ), nitrogen gas (N 2 ), and trimethyl indium gas (TMIn) to form a multi-quantum well structure. It is not limited.

The well layer / barrier layer of the active layer 144 may be formed of any one or more pair structures of InGaN / GaN, InGaN / InGaN, GaN / AlGaN, InAlGaN / GaN, GaAs (InGaAs) / AlGaAs, GaP (InGaP) / AlGaP. However, the present invention is not limited thereto. The well layer may be formed of a material having a band gap smaller than the band gap of the barrier layer.

A conductive clad layer (not shown) may be formed on or under the active layer 144. The conductive clad layer may be formed of a semiconductor having a band gap wider than the band gap of the barrier layer of the active layer 144. [ For example, the conductive clad layer may include GaN, AlGaN, InAlGaN, superlattice structure, or the like. In addition, the conductive clad layer may be doped with n-type or p-type.

The second conductive semiconductor layer 146 may be formed of a semiconductor compound. 3-group-5, group-2-group-6, and the like, and the second conductivity type dopant may be doped. For example, it may include 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). When the second conductivity type semiconductor layer 146 is a P type semiconductor layer, the second conductivity type dopant may include Mg, Zn, Ca, Sr, Ba, or the like as a P type dopant.

The first conductive semiconductor layer 142 may be a P-type semiconductor layer, and the second conductive semiconductor layer 146 may be an N-type semiconductor layer. Alternatively, the first conductive semiconductor layer 142 may be an N-type semiconductor layer, and the second conductive semiconductor layer 146 may be a P-type semiconductor layer.

The light emitting structure 140 may be implemented as any one of an N-P junction structure, a P-N junction structure, an N-P-N junction structure, and a P-N-P junction structure.

In the present embodiment described below, for convenience, the first conductivity-type semiconductor layer 142 is described as an N-type semiconductor layer, and the second conductivity-type semiconductor layer 146 is described as a P-type semiconductor layer, but the embodiments are not limited thereto. .

The surface grating reflector 150 may be provided on the surface of the light emitting structure 140, that is, the surface of the first conductivity-type semiconductor layer 142. The surface grating reflector 150 may have a concave-convex structure as shown in FIG. 1, and the concave-convex structure may be arranged regularly.

As for the characteristics of the surface grating reflector 150, the above-described OPTICS EXPRESS 22535 to 22542, Vol. 17, No. 25, 7 December 2009, “Polarization-dependent GaN surface grating reflector for short wavelength applications”, Joonhee Lee et al.

The surface grating reflector 150 may be formed on top of the light emitting structure 140 as a separate layer from the light emitting structure 140 as shown in FIG. 1, but different from that of the light emitting structure 140 as shown in FIG. 1. It may be formed directly on the first conductivity type semiconductor layer 142. That is, the surface grating reflector 150 may be made of a material different from that of the first conductive semiconductor layer 142 or may be made of the same material as the first conductive semiconductor layer 142.

If the surface grating reflector 150 is made of a material different from that of the first conductivity type semiconductor layer 142, for example, the surface grating reflector 150 may be made of a material having a refractive index of 1.5 to 2.5. It may include an oxide, and may include, for example, any one of ITO, SiO 2 , Al 2 O 3 , ZnO, TiO 2 , and a polymer. Alternatively, the material of the surface grating reflector 150 may be an imprint resin or a sol-gel solution in which nanoparticles such as TiO 2 , ZnO, and Al 2 O 3 are dispersed.

2 is a diagram showing a structure of sapphire crystal.

According to the embodiment, when the sapphire substrate is used as the substrate 110, the R-plane (1-102), which is a semi-polar plane, is used on the R-plane (1-102) as the crystal plane of the sapphire substrate. The semipolar nitride semiconductor layer is grown in the vertical direction.

In another embodiment, the substrate 110 may use a SiC substrate. When using a SiC substrate, a non-polar nitride semiconductor layer is grown in a direction perpendicular to the M-plane 10-10 using the M-plane 10-10 of SiC.

In addition, the substrate 110 may use a GaN substrate. When using a GaN substrate, a non-polar nitride semiconductor layer is grown in a direction perpendicular to the M-plane 10-10 using the M-plane 10-10 of GaN.

As described above, according to the embodiment, the first conductive semiconductor layer 142, the active layer 144, and the second conductive semiconductor layer 146 are all grown on the substrate 110 in a nonpolar or semipolar manner.

When the light emitting structure 140 is grown non-polarly, polarization is emitted in a direction perpendicular to the M-plane or a-plane. In addition, when the light emitting structure 140 is grown to be semipolar, polarization is emitted in a direction perpendicular to the R-plane.

On the other hand, according to the embodiment, the wavelength of the polarized light emitted from the light emitting device shown in FIG. 1 may vary according to the concave-convex structure of the surface grating reflector 150. That is, the concave-convex structure may be formed in accordance with the wavelength of the polarization to be emitted from the light emitting element.

The concave-convex structure of the surface grating reflector 150 shown in FIG. 1 includes a concave portion 152 and a convex portion 154, and the concave portion 152 is disposed lower than the convex portion 154. In addition, the uneven structure may have a period θ of the uneven structure, an angle θ at which the side edge of the convex portion 154 is inclined from vertical, a filling factor (F) or a height (or thickness) of the convex portion 154. (h) may be defined as at least one.

According to the embodiment, the wavelength of the polarized light emitted from the light emitting element is determined by at least one of the period Λ, the angle θ, the filling factor F or the height h.

Here, the filling factor F is represented by following formula (1).

Figure pat00001

Here, l means the length of the convex portion 154.

3 is an enlarged cross-sectional view of the surface grating reflector 150 illustrated in FIG. 1.

Referring to FIG. 3, the incident light 180 emitted from the active layer 144 and incident through the first conductive semiconductor layer 142 is diffracted while being reflected by the grating of the surface grating reflector 150. However, when the period Λ of the uneven structure in the surface grating reflector 150 is smaller than the wavelength of the light 180, diffraction does not occur in the grating. In this case, reflectances of the incident light 180 and the light 186 entering the surface grating reflector 150 from the air may be different from each other.

4A to 4C are diagrams showing diffraction efficiency spectra. 4A is a graph illustrating a relationship between diffraction efficiency and wavelength λ in case of TE (Transverse Electric) polarization, and the horizontal axis represents wavelength λ and the vertical axis represents diffraction efficiency, respectively. 4B is a graph showing the relationship between the diffraction efficiency and the wavelength [lambda] in the case of TM (Transverse Magnetic) polarization. The horizontal axis represents the wavelength [lambda] and the vertical axis represents the diffraction efficiency, respectively. 4C is a diagram showing a concentrated electric field, where the horizontal axis represents an integrated electric field and the vertical axis represents a propagation direction, respectively.

As shown in FIG. 4A, the reflectance of incident light 180 has a reflectance of 100% for TE polarization parallel to the grating. At this time, as a result of simulation by the finite-difference time-domain (FDTD) method, as shown in FIG.

Therefore, parallel light emission occurs in a direction perpendicular to the M-plane or the a-plane, which is a direction in which reflection occurs with respect to the surface lattice reflector 150, and thus resonance occurs. Therefore, the polarized light having the desired wavelength λ of which the polarization efficiency is maximized can be emitted from the light emitting element.

According to the embodiment, when the period Λ, the angle θ, the filling factor F, and the height h have a predetermined value, the polarized light 184 having a predetermined wavelength may be emitted from the light emitting device.

5A to 5C are graphs showing reflectances according to periods Λ and heights h for each wavelength λ, with the vertical axis representing the period Λ and the horizontal axis representing the height h, respectively.

As shown in FIGS. 5A-5C, the central portions 192A and 192B in the two high reflective regions 190A and 190B have a reflectivity of at least 80%. From this, when the height h is 100 nm to 250 nm and the period Λ is 250 nm to 450 nm in the first high reflection region 190A, the wavelength λ of polarized light emitted from the light emitting element is 370. It can be seen that the nm to 500nm. Further, in the second high reflection region 190B, when the height h is 450 nm to 700 nm and the period Λ is 150 nm to 450 nm, it can be seen that the wavelength λ is 370 nm to 500 nm. have.

Fig. 6 is a graph showing the relationship between wavelengths for each peeling factor when the height h is 114 nm and the period Λ is 450 nm, with the vertical axis representing the filling factor and the horizontal axis representing the wavelength lambda.

From the high reflection region 194 shown in FIG. 6, it can be seen that when the filling factor is 0.3 to 0.7, the wavelength λ is 450 nm.

FIG. 7 is a graph showing the relationship of the wavelength? For each tilted angle θ when the height h is 114 nm and the filling factor F is 0.4. The vertical axis represents the tilted angle θ. The abscissa represents the wavelength λ.

It can be seen from the graph shown in FIG. 7 that when the inclined angle θ is 0 to 20 °, the wavelength λ is 450 nm.

1, the first electrode layer 160 may be formed in contact with the surface grating reflector 150 on the first conductivity-type semiconductor layer 142. The first electrode layer 160 may be formed of metal. In addition, the first electrode layer 160 may be formed of a reflective electrode material having ohmic characteristics. For example, at least one of aluminum (Al), titanium (Ti), chromium (Cr), nickel (Ni), copper (Cu), and gold (Au) may be formed in a single layer or a multilayer structure.

Alternatively, as shown in FIG. 1, the surface grating reflector 150 may be formed on the first conductivity-type semiconductor layer 142 except for the region where the first electrode layer 160 is formed.

In addition, a passivation layer (not shown) may be formed on a side surface of the light emitting structure 140. The passivation layer may be made of an insulating material, and the insulating material may be made of a non-conductive oxide or nitride. For example, the passivation layer may include a silicon oxide (SiO 2 ) layer, an oxynitride layer, and an aluminum oxide layer.

The light emitting device according to the embodiment shown in FIG. 1 is a vertical light emitting device. Alternatively, the light emitting device according to another embodiment may have another type of vertical structure as follows.

8 is a sectional view showing a light emitting device according to another embodiment.

The light emitting device 200 illustrated in FIG. 8 includes a support substrate 210, a first electrode layer 220, an insulating layer 222, a second electrode layer 230, a light emitting structure 240, a surface grating reflector 250, and An electrode pad 260.

The support substrate 210, the light emitting structure 240, and the surface grating reflector 250 shown in FIG. 8 are the same as the support substrate 110, the light emitting structure 140, and the surface grating reflector 150 shown in FIG. Therefore, detailed description thereof will be omitted.

The first electrode layer 220 penetrates the second electrode layer 230, the second conductive semiconductor layer 246, and the active layer 244 to be in contact with the first conductive semiconductor layer 242. It is formed on the support substrate 210 from below.

The first electrode layer 220 has a lower electrode layer in contact with the support substrate 210, and at least one contact electrode 224 branched from the lower electrode layer to electrically contact the first conductive semiconductor layer 242.

A plurality of contact electrodes 224 of the first electrode layer 220 may be formed to be spaced apart from each other so as to smoothly supply current to the first conductive semiconductor layer 242. The contact electrode 224 may be at least one of a radial pattern, a cross pattern, a line pattern, a curved pattern, a loop pattern, a ring pattern, and a ring pattern, but is not limited thereto.

For example, the first electrode layer 220 may be made of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, Hf, and optional combinations thereof. In addition, the first electrode layer 220 may be formed as a single layer or multiple layers of a reflective electrode material having ohmic characteristics. For example, the first electrode layer 220 may be formed of a metal, indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), or IGTO. (indium gallium tin oxide), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IrOx, RuOx, RuOx / ITO, Ni / IrOx / Au, and Ni / IrOx / Au / ITO It may include at least one of, but is not limited to such materials. When the first electrode layer 220 plays an ohmic role, the ohmic layer may not be formed.

The second electrode layer 230 is formed on the first electrode layer 220 while contacting the second conductive semiconductor layer 246 under the light emitting structure 240.

The second electrode layer 230 may be a structure of an ohmic layer / reflection layer / bonding layer or may be stacked in a structure of a reflective layer (including ohmic) / bonding layer, but is not limited thereto. For example, the second electrode layer 230 may have a form in which the reflective layer 234 and the ohmic layer 232 are sequentially stacked on the insulating layer 222. Since the reflective layer 234 and the ohmic layer 232 are generally similar to the reflective layer 134 and the ohmic layer 132 illustrated in FIG. 1, a detailed description thereof will be omitted.

An insulating layer 222 disposed between the first electrode layer 220 and the second electrode layer 230 is formed around the first electrode layer 220 to form different layers 230, 246, and 244 from the first electrode layer 220. ) Is electrically insulated to cut off the electrical short. The insulating layer 222 may be formed of SiO 2 , SiO x , SiO x N y , Si 3 N 4 , Al 2 O 3 , but is not limited thereto.

Although not shown, a protective layer may be formed on the side surface of the light emitting structure 240. In addition, the protective layer may be formed on the top surface of the first conductivity type semiconductor layer 242, but is not limited thereto. The protective layer is formed of an insulating material to electrically protect the light emitting structure 240. The protective layer may be formed of SiO 2 , SiO x , SiO x N y , Si 3 N 4 , Al 2 O 3 , but is not limited thereto.

One region of the ohmic layer 232 and / or the reflective layer 234 may be opened, and the electrode pad 260 is formed on the opened one region. The electrode pad 260 may be in the form of an electrode.

9 is a diagram illustrating an application example of a light emitting device according to an embodiment.

As shown in Fig. 9, in the media 292, 294 and 296 having different refractive indices n1, n2 and n3, respectively, when polarized light having a predetermined wavelength emits light from the light emitting element 290, Since the polarized light of the eigen mode is well transmitted, a more efficient light guide plate can be made when the corresponding polarization is transmitted through the medium 294.

The light emitting device 290 illustrated in FIG. 9 corresponds to the light emitting device 100 or 200 illustrated in FIG. 1 or 8.

10A to 10E are views illustrating an embodiment of a manufacturing method of the light emitting device shown in FIG. 1.

As shown in FIG. 10A, a light emitting structure 140 including a buffer layer 90, a first conductivity type semiconductor layer 142, an active layer 144, and a second conductivity type semiconductor layer 146 on a substrate 80. ) Grow nonpolar or semipolar.

The light emitting structure 140 may include, for example, Metal Organic Chemical Vapor Deposition (MOCVD), Chemical Vapor Deposition (CVD), Plasma-Enhanced Chemical Vapor Deposition (PECVD), and molecular beam growth. It may be formed using a method such as Molecular Beam Epitaxy (MBE), Hydride Vapor Phase Epitaxy (HVPE), but is not limited thereto.

The substrate 80 may include a conductive substrate or an insulating substrate, and for example, may use at least one of sapphire (Al 2 O 3 ), SiC, GaAs, GaN, ZnO, Si, GaP, InP, Ge, and Ga 2 0 3 . have. An uneven structure may be formed on the substrate 80, but is not limited thereto. Impurities on the surface may be removed by wet cleaning the substrate 80.

The buffer layer 90 may be grown between the light emitting structure 140 and the substrate 80 to mitigate the difference in lattice mismatch and thermal expansion coefficient of the material. The material of the buffer layer 90 may be formed of at least one of Group III-V compound semiconductors, for example, GaN, InN, AlN, InGaN, AlGaN, InAlGaN, and AlInN. An undoped semiconductor layer may be formed on the buffer layer 90, but is not limited thereto.

The light emitting structure 140 may be grown non-polarly or semi-polarly by vapor deposition such as metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), and hydraulic vapor phase epitaxy (HVPE).

The composition of the first conductive semiconductor layer 142 is the same as described above, and is N-type using a method such as chemical vapor deposition (CVD) or molecular beam epitaxy (MBE) or sputtering or hydroxide vapor phase epitaxy (HVPE). The GaN layer can be formed nonpolar or semipolar. In addition, the first conductive semiconductor layer 142 may include a silane gas containing n-type impurities such as trimethyl gallium gas (TMGa), ammonia gas (NH 3 ), nitrogen gas (N 2 ), and silicon (Si) in the chamber. (SiH 4 ) may be implanted to form nonpolar or semipolar.

The composition of the active layer 144 is the same as described above, for example, the trimethyl gallium gas (TMGa), ammonia gas (NH 3 ), nitrogen gas (N 2 ), and trimethyl indium gas (TMIn) is injected to multi-quantum The well structure may be formed non-polar or semi-polar, but is not limited thereto.

The second conductive semiconductor layer 146 has the same composition as described above, and has a p-type such as trimethyl gallium gas (TMGa), ammonia gas (NH 3 ), nitrogen gas (N 2 ), and magnesium (Mg) in the chamber. Non-cetyl cyclopentadienyl magnesium (EtCp 2 Mg) {Mg (C 2 H 5 C 5 H 4 ) 2 } containing impurities may be implanted into the p-type GaN layer to be nonpolar or semipolar, but is not limited thereto. It is not.

As illustrated in FIG. 10B, an ohmic layer 132 and a reflective layer 134 may be formed on the light emitting structure 140. The composition of the ohmic layer 132 and the reflective layer 134 is as described above, and may be formed by sputtering or electron beam deposition.

As illustrated in FIG. 10C, the bonding layer 120 and the conductive support substrate 110 may be formed on the reflective layer 134. The conductive support substrate 110 may be formed using an electrochemical metal deposition method, a bonding method using an etchant metal, or the like, and may form a separate bonding layer 120.

Then, the substrate 80 is separated as shown in FIG. 10D. The substrate 80 may be removed by a laser lift off (LLO) method using an excimer laser or the like, or may be a method of dry and wet etching.

For example, when the laser lift-off method focuses and irradiates excimer laser light having a predetermined wavelength toward the substrate 80, thermal energy is concentrated on the interface between the substrate 80 and the light emitting structure 140. As the interface is separated into gallium and nitrogen molecules, the substrate 80 is instantaneously separated at the portion where the laser light passes, and the buffer layer 90 may be separated together.

In addition, each light emitting structure 140 may be diced by element.

After inverting the structure shown in FIG. 10D as illustrated in FIG. 10E, the surface lattice reflector layer 150 is laminated on the surface of the first conductivity-type semiconductor layer 142, which may be stacked by spin coating or the like. .

The surface grating reflector layer 150 is then patterned to form the surface grating reflector 150 as shown in FIG. 1. Thereafter, the first electrode layer 160 is formed by a conventional method.

11 is a view showing an embodiment of a light emitting device package.

The light emitting device package 300 according to the embodiment may be installed in the package body 310, the first lead frame 321 and the second lead frame 322 installed in the package body 310, and the package body 310. The light emitting device 100 is electrically connected to the first lead frame 321 and the second lead frame 322, and a molding part 350 covering the surface or the side surface of the light emitting device 100.

The package body 310 may include a silicon material, a synthetic resin material, or a metal material. An inclined surface may be formed around the light emitting device 100 to increase light extraction efficiency.

The first lead frame 321 and the second lead frame 322 are electrically separated from each other, and provide power to the light emitting device 100. In addition, the first lead frame 321 and the second lead frame 322 may increase the light efficiency by reflecting the light generated from the light emitting device 100, the heat generated from the light emitting device 100 to the outside It can also play a role.

The light emitting device 100 may be installed on the package body 310 or on the first lead frame 321 or the second lead frame 322. The light emitting device 100 may be electrically connected to the first lead frame 321 and the second lead frame 322 by any one of a wire method, a flip chip method, or a die bonding method. In the present exemplary embodiment, the light emitting device 100 is connected to the first lead frame 321 and the conductive adhesive layer 330 and is bonded to the second lead frame 322 and the wire 340.

The molding part 350 may surround and protect the light emitting device 100. In addition, the phosphor 355 may be included in the molding part 350 to change the wavelength of the light emitted from the light emitting device 100.

In the light emitting device package 300 according to the embodiment, the light extraction structure may be disposed in the light emitting device 100 to improve the light extraction characteristics.

The light emitting device package 300 may be mounted on one or a plurality of light emitting devices according to the embodiments described above, but the present invention is not limited thereto.

A plurality of light emitting device packages according to the embodiment may be arranged on a substrate, and a light guide plate, a prism sheet, a diffusion sheet, or the like, which is an optical member, may be disposed on an optical path of the light emitting device package. Such a light emitting device package, a substrate, and an optical member can function as a light unit. Another embodiment may be implemented as a display device, an indicator device, or a lighting system including the semiconductor light emitting device or the light emitting device package described in the above embodiments, and for example, the lighting system may include a lamp or a street lamp. . Hereinafter, a head lamp and a backlight unit will be described as an embodiment of an illumination system in which the above-described light emitting device package is disposed.

12 is a diagram illustrating an embodiment of a head lamp including a light emitting device package.

The light emitted from the light emitting device module 401 in which the light emitting device package is disposed is reflected by the reflector 402 and the shade 403 and then transmitted through the lens 404 to the front of the vehicle body You can head.

As described above, since the light extraction efficiency of the light emitting device used in the light emitting device module 401 can be improved, the optical characteristics of the entire head lamp can be improved.

The light emitting device package included in the light emitting device module 401 may include a plurality of the light emitting devices described above, but is not limited thereto.

13 is a view illustrating an embodiment of a display device including a light emitting device package.

As shown, the display device 500 according to the present exemplary embodiment includes a light source module, a reflector 520 on the bottom cover 510, and light emitted from the light source module disposed in front of the reflector 520. A light guide plate 540 to guide forward, a first prism sheet 550 and a second prism sheet 560 disposed in front of the light guide plate 540, and a panel disposed in front of the second prism sheet 560 ( 570 and a color filter 580 disposed throughout the panel 570.

The light source module comprises a light emitting device package 535 on a circuit board 530. Here, the circuit board 530 may be a PCB, etc., the light emitting device package 535 is as described with reference to FIG.

The bottom cover 510 may accommodate components in the display device 500. The reflecting plate 520 may be provided as a separate component as shown in the figure, or may be provided in the form of coating with a highly reflective material on the back of the light guide plate 540, or the front of the bottom cover 510.

The reflector 520 can be made of a material having a high reflectance and can be used in an ultra-thin shape, and a polyethylene terephthalate (PET) can be used.

The light guide plate 540 scatters the light emitted from the light emitting device package module so that the light is uniformly distributed over the entire screen area of the LCD. Therefore, the light guide plate 540 is made of a material having a good refractive index and a high transmittance, and may be formed of polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene (PE), or the like. Also, if the light guide plate 540 is omitted, an air guide display device can be realized.

The first prism sheet 550 is formed of a translucent and elastic polymer material on one surface of the support film, and the polymer may have a prism layer in which a plurality of three-dimensional structures are repeatedly formed. Here, as shown in the drawings, the plurality of patterns may be provided with a floor and a valley repeatedly as stripes.

In the second prism sheet 560, the direction of the floor and the valley of one surface of the support film may be perpendicular to the direction of the floor and the valley of one surface of the support film in the first prism sheet 550. This is to evenly distribute the light transmitted from the light source module and the reflective sheet in the front direction of the panel 570.

In the present embodiment, the first prism sheet 550 and the second prism sheet 560 constitute an optical sheet, which is composed of another combination, for example, a micro lens array or a combination of a diffusion sheet and a micro lens array, or It may be made of a combination of one prism sheet and a micro lens array.

The liquid crystal display panel (Liquid Crystal Display) may be disposed in the panel 570, and other types of display devices requiring a light source may be provided in addition to the liquid crystal display panel.

The panel 570 is in a state where the liquid crystal is located between the glass bodies and the polarizing plates are placed on both glass bodies in order to use the polarization of light. Here, the liquid crystal has an intermediate property between a liquid and a solid, and liquid crystals, which are organic molecules having fluidity like a liquid, are regularly arranged like crystals. The liquid crystal has a structure in which the molecular arrangement is changed by an external electric field And displays an image.

A liquid crystal display panel used in a display device is an active matrix type, and a transistor is used as a switch for controlling a voltage supplied to each pixel.

The front surface of the panel 570 is provided with a color filter 580 to transmit the light projected by the panel 570, only the red, green, and blue light for each pixel can represent the image.

In the display device 500 according to the exemplary embodiment, the light extraction efficiency of the light emitting device used for the light emitting device package 535 may be improved, and thus the optical characteristics of the display device may be improved.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

80: substrate 90: buffer layer
100, 200, 290: light emitting elements 110, 210: conductive support substrate
120: adhesive layer 134, 234: reflective layer
132 and 232: ohmic layer 140 and 240: light emitting structure
142 and 242: first conductive semiconductor layer 144 and 244 active layer
146 and 246: Second conductivity type semiconductor layers 150 and 250: Surface grating reflector
160 and 220: first electrode layer 222: insulating layer
224: contact electrode 230: second electrode layer
292, 294, and 296: medium 300: light emitting device package
310: package body 321: first lead frame
322: second lead frame 330: conductive adhesive layer
340: wire 350: molding part
355: phosphor 400: headlamp
401 light emitting device module 402 reflector
403: Shade 404: Lens
500: display unit 510: bottom cover
520: reflector 540: light guide plate
550: first prism sheet 560: second prism sheet
570: panel 580: color filter

Claims (17)

In the light emitting device,
A light emitting structure 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, each of which is grown in a non-polar direction; And
A surface grating reflector disposed on the light emitting structure,
And a polarization light having a wavelength corresponding to the structure of the surface grating reflector is emitted from the light emitting element. The light emitting device of claim 1, wherein the polarized light is emitted in a direction perpendicular to the M-plane. The light emitting device of claim 1, wherein the polarized light is emitted in a direction perpendicular to the a-plane. In the light emitting device,
A light emitting structure comprising 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, each of which is grown in a semipolar direction; And
A surface grating reflector disposed on the light emitting structure,
And a polarization light having a wavelength corresponding to the structure of the surface grating reflector is emitted from the light emitting element. The light emitting device of claim 4, wherein the polarized light is emitted in a direction perpendicular to the R-plane. The light emitting device according to claim 1 or 4, wherein the surface grating reflector has an uneven structure. The light emitting device according to claim 1 or 4, wherein the surface lattice reflector is made of the same material as the first conductive semiconductor layer. The light emitting device according to claim 1 or 4, wherein the surface lattice reflector is made of a material different from that of the first conductive semiconductor layer. The method according to claim 1 or 4,
A first electrode layer formed on the light emitting structure and in contact with the first conductive semiconductor layer; And
And a second electrode layer formed under the light emitting structure and in contact with the second conductive semiconductor layer. The method according to claim 1 or 4,
A first electrode layer; And
A second electrode layer formed under the light emitting structure and in contact with the second conductive semiconductor layer;
The first electrode layer is formed under the second electrode layer and in contact with the first conductive semiconductor layer through the second electrode layer, the second conductive semiconductor layer and the active layer. The light emitting device of claim 6, wherein the uneven structure is regularly arranged. The method of claim 6, wherein at least one of a period of the uneven structure, an angle at which a side edge of the convex portion is inclined in the uneven structure, a peeling factor to the uneven structure, or a height of the convex portion has a value corresponding to the wavelength of the polarized light. Having a light emitting device. The light emitting device of claim 6, wherein a wavelength of light emitted from the active layer is smaller than the period. The light emitting device of claim 12, wherein the height is 100 nm to 250 nm, and the period is 250 nm to 450 nm, and the wavelength is 370 nm to 500 nm. The light emitting device of claim 12, wherein the height is 450 nm to 700 nm, and the period is 150 nm to 450 nm, and the wavelength is 370 nm to 500 nm. The light emitting device of claim 12, wherein the height is 114 nm, the period is 450 nm, and the filling factor is 0.3 to 0.7 when the wavelength is 450 nm. The light emitting device of claim 12, wherein the height is 114 nm, the filling factor is 0.4, and the angle is 0 to 20 °.
KR1020110114263A 2011-11-04 2011-11-04 Light emitting device KR20130049316A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20150092899A (en) * 2014-02-06 2015-08-17 엘지이노텍 주식회사 Light Emitting Device
KR20160038127A (en) * 2014-09-29 2016-04-07 엘지이노텍 주식회사 Light emitting device and lighting system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20150092899A (en) * 2014-02-06 2015-08-17 엘지이노텍 주식회사 Light Emitting Device
KR20160038127A (en) * 2014-09-29 2016-04-07 엘지이노텍 주식회사 Light emitting device and lighting system

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