KR102249648B1 - Red light emitting device and lighting system - Google Patents

Abstract

The embodiment relates to a red light emitting device, a method of manufacturing a light emitting device, a light emitting device package, and a lighting system.
The red light emitting device according to the embodiment includes a conductive support member 70; A semiconductor reflective layer 55 on the conductive support member 70; A first conductivity type semiconductor layer 112 on the semiconductor reflective layer 55; An active layer 114 on the first conductivity type semiconductor layer 112; A second conductivity type semiconductor layer 116 on the active layer 114; And a first electrode 81 on the second conductivity type semiconductor layer 116.
The semiconductor reflective layer 55 includes a central portion overlapping the first electrode 81 and upper and lower portions, and an outer portion that does not overlap between the first electrode 81 and the upper and lower portions, and the semiconductor reflective layer 55 is formed at the central portion. The thickness may decrease in the direction of the outer portion.

Description

Red light emitting device and lighting system {RED LIGHT EMITTING DEVICE AND LIGHTING SYSTEM}

The embodiment relates to a red light emitting device, a method of manufacturing a light emitting device, a light emitting device package, and a lighting system.

Light Emitting Device (LED) is a pn junction diode that converts electrical energy into light energy by combining elements of Group III and Group V on the periodic table, and LED can be produced by controlling the composition ratio of compound semiconductors. Various colors can be implemented.

Nitride semiconductors are attracting great interest in the development of optical devices and high-power electronic devices due to their high thermal stability and wide bandgap energy. In particular, a blue light emitting device, a green light emitting device, an ultraviolet (UV) light emitting device, and a red light emitting device using a nitride semiconductor have been commercialized and widely used.

For example, there is an AlInGaP-based light-emitting diode as a red light-emitting device, which can convert injected electrical energy into light having a specific wavelength within a range of about 570 nm to about 630 nm. The change of a specific wavelength depends on the size of the band gap of the light emitting diode, and the band gap size can be adjusted by changing the composition ratio of Al and Ga. For example, the wavelength decreases as the composition ratio of Al increases.

Recently, the AlInGaP-based red LED is expanding its application area as a High CRI (Color Rendering Index) illumination light source or vehicle light source, and accordingly, market competition is intensifying, and securing high light output is emerging as an important issue.

The embodiment is to provide a red light emitting device capable of improving light output, a method of manufacturing a light emitting device, a light emitting device package, and a lighting system.

The red light emitting device according to the embodiment includes a conductive support member 70; A semiconductor reflective layer 55 on the conductive support member 70; A first conductivity type semiconductor layer 112 on the semiconductor reflective layer 55; An active layer 114 on the first conductivity type semiconductor layer 112; A second conductivity type semiconductor layer 116 on the active layer 114; And a first electrode 81 on the second conductivity type semiconductor layer 116.

The semiconductor reflective layer 55 includes a central portion overlapping the first electrode 81 and upper and lower portions, and an outer portion that does not overlap between the first electrode 81 and the upper and lower portions, and the semiconductor reflective layer 55 is formed at the central portion. The thickness may decrease in the direction of the outer portion.

In addition, the red light emitting device according to the embodiment includes a conductive support member 70; Metal reflective layer 57 on the conductive support member 70: a semiconductor reflective layer 55 on the metal reflective layer 57; A first conductivity type semiconductor layer 112 on the semiconductor reflective layer 55; An active layer 114 on the first conductivity type semiconductor layer 112; A second conductivity type semiconductor layer 116 on the active layer 114; And a first electrode 81 on the second conductivity type semiconductor layer 116.

The lighting system according to the embodiment may include a light emitting unit including the red light emitting device.

The embodiment can provide a red light emitting device capable of improving light output, a method of manufacturing a light emitting device, a light emitting device package, and a lighting system.

1 is a cross-sectional view of a red light emitting device according to a first embodiment.
2 is a relationship data of the incident angle and reflectivity of light emitted from the light emitting device to the DBR.
3 is a schematic diagram of light emission distribution in a red light emitting device according to an embodiment.
4 is a cross-sectional view of a red light emitting device according to a second embodiment.
5 to 9 are cross-sectional views illustrating a method of manufacturing a red light emitting device according to an embodiment.
10 is a cross-sectional view of a light emitting device package according to an embodiment.
11 is a perspective view of a lighting device according to the embodiment.

In the description of the embodiment, each layer (film), region, pattern, or structure is "on/over" or "under" of the substrate, each layer (film), region, pad, or patterns. In the case of being described as being formed in, "on/over" and "under" include both "directly" or "indirectly" formed. do. In addition, the criteria for the top/top or bottom of each layer will be described based on the drawings.

(Example)

1 is a cross-sectional view of a red light emitting device 100 according to a first embodiment.

The light emitting device 100 according to the first embodiment includes a conductive support member 70, a semiconductor reflective layer 55 on the conductive support member 70, and a first conductive type semiconductor layer on the semiconductor reflective layer 55. 112, an active layer 114 on the first conductivity type semiconductor layer 112, a second conductivity type semiconductor layer 116 on the active layer 114, and the second conductivity type semiconductor layer 116 ) May include a first electrode 81 on it. The second conductivity type semiconductor layer 116, the active layer 114, and the first conductivity type semiconductor layer 112 may be defined as a light emitting structure 110. The embodiment may include a metal layer 60 between the semiconductor reflective layer 55 and the conductive support member 70. The embodiment is to provide a red light emitting device capable of improving light output, a method of manufacturing a light emitting device, a light emitting device package, and a lighting system.

In a vertical light emitting device in which an electrode is disposed above and below a light emitting area among red LEDs, a Distributed Bragg-Reflector (DBR) is disposed under the light emitting area as a reflective layer in order to direct the light emission distribution upward.

On the other hand, in the red LED of the prior art, since the structure of the AlInGaP LED is not good, the emission area in the active layer MQW tends to be concentrated in the center.

The light generated in the centrally concentrated light emitting area spreads in all directions, and is incident on the DBR (Distributed Bragg-Reflector) at various angles. At this time, the angle of incident to the DBR increases as the light directed to the outer side of the light emitting device chip increases, but the conventional technology uniformly forms the DBR without considering the incident light from various angles, thereby reducing the light output.

FIG. 2 is data on a relationship between an incident angle and reflectivity of light emitted from a light emitting device to a Distributed Bragg-Reflector (DBR).

As shown in FIG. 2, at a small incident angle (θ) of about 4° to about 5°, the reflectivity increases as the number of pairs of DBRs increases. Tends to decline sharply.

Accordingly, the embodiment intends to provide a red light emitting device having an optimal semiconductor reflective layer in consideration of the relationship between the number of pairs of DBRs and reflectivity.

3 is a schematic diagram of light emission distribution in a red light emitting device according to an embodiment.

In an embodiment, the semiconductor reflective layer 55 may include a super lattice layer by alternately stacking one or more pairs of a first refractive layer having a first refractive index and a second refractive layer having a second refractive index greater than the first refractive index.

In the embodiment, the reflection effect in the semiconductor reflective layer 55 may be caused by constructive interference of light waves, and the second refractive layer having a large refractive index is located at the outermost layer into which light enters, and the thickness of the second refractive layer having a large refractive index The reinforcing interference may be increased by making it thinner than the thickness of the first refractive layer having a small refractive index, and accordingly, the reflection effect may be increased, thereby increasing the light extraction efficiency.

The semiconductor reflective layer 55 may include an AlAs layer (not shown)/AlGaAs layer (not shown), and the semiconductor reflective layer 55 may be doped with a first conductivity type dopant, but is not limited thereto.

The Al composition of the AlAs layer may be higher than the Al composition of the AlGaAs layer, and the semiconductor reflective layer 55 having this structure can effectively reflect light of a wavelength in the red range.

In an exemplary embodiment, the semiconductor reflective layer 55 may include a central portion overlapping the first electrode 81 and the top and bottom, and an outer portion that does not overlap the first electrode 81 and the top and bottom.

In this case, the thickness of the semiconductor reflective layer 55 may decrease from the central portion toward the outer portion.

For example, the upper surface of the semiconductor reflective layer 55 may be a flat surface, and the thickness of the lower surface of the semiconductor reflective layer 55 may decrease from a central portion toward the outer portion.

For example, the upper surface of the semiconductor reflective layer 55 may refer to the direction of the second conductive type semiconductor layer 116, and the lower surface of the semiconductor reflective layer 55 may refer to the direction of the conductive support member 70. However, it is not limited thereto.

As shown in FIG. 3, according to the embodiment, the incident angle of light toward the outer portion of the chip to the semiconductor reflective layer 55 is greater than the central portion.

Accordingly, in the embodiment, the outer portion of the semiconductor reflective layer 55 in which the second incidence angle θ2, which is a larger incidence angle than the central portion, is formed, is more By designing so that the number of pairs is small, optimum reflection efficiency can be obtained.

This is because, as shown in FIG. 2, in the case of a large incident angle in which the incident angle exceeds about 5°, the decrease in the number of pairs of the semiconductor reflective layer 55 increases the reflectance.

Accordingly, in the embodiment, the semiconductor reflective layer 55 is designed to decrease in thickness from the center to the outer portion, so that the number of pairs of the semiconductor reflective layer 55 decreases toward the outer side of the chip, so that the semiconductor reflective layer for light incident at a large angle ( 55) can increase the reflection efficiency.

4 is a cross-sectional view of a red light emitting device 102 according to a second embodiment.

The red light emitting device 102 according to the second embodiment includes a conductive support member 70, a metal reflective layer 57 on the conductive support member 70, and a semiconductor reflective layer 55 on the metal reflective layer 57. And, a second conductivity type semiconductor layer 116 on the semiconductor reflective layer 55, an active layer 114 on the second conductivity type semiconductor layer 116, and a first conductivity type on the active layer 114 A semiconductor layer 112 and a first electrode 81 on the first conductivity type semiconductor layer 112 may be included.

The second embodiment can adopt the technical features of the first embodiment. For example, the semiconductor reflective layer 55 includes a central portion overlapping the first electrode 81 and upper and lower portions, and an outer portion that does not overlap between the first electrode 81 and the upper and lower portions, and the semiconductor reflective layer 55 The thickness may decrease from the central portion toward the outer portion.

Hereinafter, the main features of the second embodiment will be described mainly.

In the second embodiment, the metal reflective layer 57 may be disposed between the semiconductor reflective layer 55 and the conductive support member 70.

The metal reflective layer 57 may be formed of a material having excellent reflectivity and excellent electrical contact. For example, the metal reflective layer 57 may be formed of a metal or alloy including at least one of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, and Hf.

The second embodiment may further increase light extraction efficiency by providing the metal reflective layer 57 under the semiconductor reflective layer 55.

In the second embodiment, the metal reflective layer 57 may have a curved surface at the outer portion of the semiconductor reflective layer 55, and through this, the reflectance may be increased by reducing an incident angle.

Hereinafter, a method of manufacturing a red light emitting device according to an embodiment will be described with reference to FIGS. 5 to 9. 5 to 9 illustrate the manufacturing method based on the first embodiment, but the embodiment is not limited thereto, and when necessary, features of the manufacturing method of the second embodiment will be described.

According to the method of manufacturing a red light emitting device according to the embodiment, as shown in FIG. 5, a first conductivity type semiconductor layer 112, an active layer 114, and a second conductivity type semiconductor layer 116 may be formed on the substrate 5. have. The first conductivity type semiconductor layer 112, the active layer 114, and the second conductivity type semiconductor layer 116 may be defined as a light emitting structure 110.

The substrate 5 may be formed of at least one of, for example, GaAs, a sapphire substrate (Al ₂ O ₃ ), SiC, GaN, ZnO, Si, GaP, InP, and Ge, and the substrate 5 has a first A conductivity-type dopant, for example, an n-type dopant may be doped, but is not limited thereto. A buffer layer may be further formed between the first conductivity type semiconductor layer 112 and the substrate 5.

The buffer layer can alleviate mismatch between the material of the light emitting structure 110 and the substrate 5, and the material of the buffer layer is a group 3-5 compound semiconductor such as AlGaP, AInGaP, GaN, InN, AlN, InGaN, It may be formed of at least one of AlGaN, InAlGaN, and AlInN, but is not limited thereto.

Next, a preliminary semiconductor reflective layer 55a is formed on the substrate 5 or the buffer layer. The preliminary semiconductor reflective layer 55a may form a superlattice layer by alternately stacking at least one pair of a first refractive layer having a first refractive index and a second refractive layer having a second refractive index greater than the first refractive index. The preliminary semiconductor reflective layer 55a may be formed in situ in MOCVD together with the light emitting structure 110 to be formed later, but is not limited thereto.

In the embodiment, the reflection effect in the preliminary semiconductor reflective layer 55a is caused by the constructive interference of light waves. The second refractive layer having a large refractive index is located on the outermost layer into which light enters, and the thickness of the second refractive layer having a large refractive index By making it thinner than the thickness of the first refractive layer having a small refractive index, the constructive interference can be increased, so that the reflection effect can be increased and the light extraction efficiency can be increased.

The preliminary semiconductor reflective layer 55a may include an AlAs layer/AlGaAs layer, and the semiconductor reflective layer 55 may be doped with a first conductivity type dopant, but is not limited thereto.

Next, a first conductivity type semiconductor layer 112 may be formed on the preliminary semiconductor reflective layer 55a.

The first conductivity-type semiconductor layer 112 may be formed of an n-type semiconductor layer to which an n-type dopant is added as a first conductivity-type dopant, and the second conductivity-type semiconductor layer 116 is a second conductivity-type dopant. It may be formed of a p-type semiconductor layer to which a p-type dopant is added. Meanwhile, the first conductivity-type semiconductor layer 112 may be formed as a p-type semiconductor layer, and the second conductivity-type semiconductor layer 116 may be formed as an n-type semiconductor layer.

Specifically, the first conductivity-type semiconductor layer 112 is In _x Al _y Ga _1-xy P (0≤x≤1, 0≤y≤1, 0≤x+y≤1) or In _x Al _y Ga _{It may be formed of a semiconductor material having a composition formula of 1-xy} N (0≦x≦1, 0≦y≦1, 0≦x+y≦1). For example, the first conductivity type semiconductor layer 112 may be selected from InAlGaP, AlGaP, InGaP, InAlGaN, GaN, AlGaN, AlInN, InGaN, AlN, InN, etc., and Si, Ge, Sn, Se, Te, etc. The n-type dopant of may be doped.

In the embodiment, a strain control layer may be formed on the first conductivity type semiconductor layer 112.

For example, the strain control layer is formed of In _y Al _x Ga _(1-xy) N(0≤x≤1, 0≤y≤1)/GaN, etc., so that the first conductivity type semiconductor layer 112 and the active layer ( 114), it can effectively alleviate the odd stress in the grid mismatch.

In addition, as the strain control layer is _{stacked in a superlattice structure having a composition such as first In x1} GaN and second In _x2 GaN, more electrons are collected at a low energy level of the active layer 114, and as a result, electrons and The probability of recombination of holes is increased, so that luminous efficiency may be improved.

In the active layer 114, electrons (or holes) injected through the first conductivity-type semiconductor layer 112 and holes (or electrons) injected through the second conductivity-type semiconductor layer meet each other, It is a layer that emits light by a difference in band gap energy according to.

The active layer 114 may be formed in any one of a single well structure, a multiple well structure, a quantum dot structure, or a quantum wire structure, but is not limited thereto.

The active layer 114 has _{a composition formula of In x} Al _y Ga _1-xy P (0≤x≤1, 0≤y≤1, 0≤x+y≤1) or In _x Al _y Ga _1-xy N (0 It may be formed of a semiconductor material having a composition formula of ≤x≤1, 0≤y≤1, and 0≤x+y≤1).

When the active layer 114 is formed in the multi-well structure, the active layer 114 may be formed by stacking a plurality of quantum wells and quantum walls. For example, the active layer 114 may include an InGaP/AlInGaP structure, but is not limited thereto.

The second conductivity type semiconductor layer 116 is In _x Al _y Ga _1-xy P (0≤x≤1, 0≤y≤1, 0≤x+y≤1) or In _x Al _y Ga _1-xy It may be formed of a semiconductor material having a composition formula of N (0≦x≦1, 0≦y≦1, 0≦x+y≦1).

For example, the second conductivity type semiconductor layer 116 may be selected from GaP, InAlGaP, AlGaP, InGaP, InAlGaN, GaN, AlGaN, AlInN, InGaN, AlN, InN, etc., and Mg, Zn, Ca, Sr, A p-type dopant such as Ba may be doped.

The first conductivity-type semiconductor layer 112 may include a p-type semiconductor layer, and the second conductivity-type semiconductor layer 116 may include an n-type semiconductor layer.

In addition, a semiconductor layer including an n-type or p-type semiconductor layer may be further formed on the second conductivity-type semiconductor layer 116, and accordingly, the light emitting structure 110 is np, pn, npn, pnp junction It may have at least any one of the structures.

Next, as shown in FIG. 6, a first electrode 81 may be formed on the second conductivity type semiconductor layer 116.

The first electrode 81 may be electrically connected to the second conductivity type semiconductor layer 116. A partial region of the first electrode 81 may contact the second conductivity type semiconductor layer 116.

The first electrode 81 may include an ohmic layer, an intermediate layer, and an upper layer. The ohmic layer may implement ohmic contact by including a material selected from Cr, V, W, Ti, and Zn. The intermediate layer may be implemented with a material selected from Ni, Cu, Al, or the like. The upper layer may include Au, for example.

Meanwhile, in another embodiment, the first electrode 81 may be formed after the conductive support member 70 described in FIG. 9 is formed.

Next, as shown in FIG. 7, the remaining substrate 5a may be formed by partially removing the substrate 5. The substrate 5 may be physically ground or chemically etched, but is not limited thereto.

Next, as shown in FIG. 8, the semiconductor reflective layer 55 may be formed by partially removing the remaining substrate 5a and the preliminary semiconductor reflective layer 55a.

For example, after the remaining portion 5a of the substrate is removed by etching or the like, a predetermined etching mask pattern (not shown) is formed, and the thickness is reduced from the center of the semiconductor reflective layer 55 to the outer portion by wet etching or the like. Can be formed to do so. Similar to the shape of the semiconductor reflective layer 55, the mask pattern may have a thick central portion and gradually thinner toward an outer portion.

In the embodiment, the semiconductor reflective layer 55 is designed to decrease in thickness from the center to the outer portion, and the number of pairs of the semiconductor reflective layer 55 decreases toward the outer side of the chip, so that the semiconductor reflective layer 55 for light incident at a large angle is reduced. ) Can increase the reflection efficiency.

Meanwhile, as shown in FIG. 4, the embodiment may further increase light extraction efficiency by including a metal reflective layer 57 between the semiconductor reflective layer 55 and the conductive support member 70.

The metal reflective layer 57 may be formed of a material having excellent reflectivity and excellent electrical contact. For example, the metal layer 57 may be formed of a metal or alloy including at least one of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, and Hf.

In an embodiment, the metal reflective layer 57 may have a curved surface at the outer portion of the semiconductor reflective layer 55, and through this, the reflectance may be increased by reducing an incident angle.

Next, as shown in FIG. 9, a metal layer 60 and a conductive support member 70 may be formed on the semiconductor reflective layer 55.

The metal layer 60 may be formed of a material having excellent electrical contact. For example, the metal layer 60 may be formed of a metal or alloy including at least one of Pd, Ir, Ru, Mg, Zn, Pt, Ag, Ni, Al, Rh, Au, and Hf.

The support member 70 is, for example, Ti, Cr, Ni, Al, Pt, Au, W, Cu, Mo, Cu-W or a semiconductor substrate implanted with impurities (for example, Si, Ge, GaN, GaAs, ZnO, SiC, SiGe, etc.) may be formed of at least one of.

10 is a view showing a light emitting device package to which a light emitting device according to an embodiment is applied.

Referring to FIG. 10, a light emitting device package according to an embodiment includes a body 120, a first lead electrode 131 and a second lead electrode 132 disposed on the body 120, and the body 120 It may include a light emitting device 100 provided in the first lead electrode 131 and electrically connected to the second lead electrode 132, and a molding member 140 surrounding the light emitting device 100. .

The body 120 may be formed of a silicon material, a synthetic resin material, or a metal material, and an inclined surface may be formed around the light emitting device 100.

The first lead electrode 131 and the second lead electrode 132 are electrically separated from each other, and supply power to the light emitting device 100. In addition, the first lead electrode 131 and the second lead electrode 132 reflect light generated from the light emitting device 100 to increase light efficiency, and heat generated from the light emitting device 100 It can also play a role of discharging to outside.

The light emitting device 100 may be disposed on the body 120 or may be disposed on the first lead electrode 131 or the second lead electrode 132.

The light emitting device 100 may be electrically connected to the first lead electrode 131 and the second lead electrode 132 by any one of a wire method, a flip chip method, or a die bonding method.

The molding member 140 may surround the light emitting device 100 to protect the light emitting device 100. In addition, a phosphor (not shown) may be included in the molding member 140 to change a wavelength of light emitted from the light emitting device 100.

A plurality of light emitting devices or light emitting device packages according to the embodiment may be arrayed on a substrate, and an optical member such as a lens, a light guide plate, a prism sheet, and a diffusion sheet 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 may function as a light unit. The light unit may be implemented in a top view or a side view type, and may be provided to a display device such as a portable terminal and a notebook computer, or may be variously applied to a lighting device and an indication device.

Another embodiment may be implemented as a lighting device including the light emitting device or the light emitting device package described in the above-described embodiments. For example, the lighting device may include a lamp, a street light, an electric sign, and a headlamp.

11 is an exploded perspective view of a lighting device according to an embodiment.

The lighting device according to the embodiment may include a cover 2100, a light source module 2200, a radiator 2400, a power supply unit 2600, an inner case 2700, and a socket 2800. In addition, the lighting device according to the embodiment may further include at least one of the member 2300 and the holder 2500. The light source module 2200 may include a light emitting device or a light emitting device package according to the embodiment.

The light source module 2200 may include a light source unit 2210, a connection plate 2230, and a connector 2250. The member 2300 is disposed on the upper surface of the radiator 2400 and has guide grooves 2310 into which a plurality of light source units 2210 and a connector 2250 are inserted.

The holder 2500 blocks the receiving groove 2719 of the insulating part 2710 of the inner case 2700. Accordingly, the power supply unit 2600 accommodated in the insulating unit 2710 of the inner case 2700 is sealed. The holder 2500 has a guide protrusion 2510.

The power supply unit 2600 may include a protrusion 2610, a guide portion 2630, a base 2650, and an extension 2670. The inner case 2700 may include a molding unit together with the power supply unit 2600 therein. The molding portion is a portion in which the molding liquid is solidified, and allows the power supply unit 2600 to be fixed inside the inner case 2700.

A plurality of light emitting devices according to the embodiment may be arrayed on a substrate in the form of a package, and an optical member, such as a light guide plate, a prism sheet, a diffusion sheet, and a fluorescent sheet, may be disposed on a path of light emitted from the light emitting device package.

The light emitting device according to the embodiment may be applied to a backlight unit, a lighting unit, a display device, an indication device, a lamp, a street light, a vehicle lighting device, a vehicle display device, a smart watch, etc., but is not limited thereto.

Features, structures, effects, and the like described in the embodiments above are included in at least one embodiment, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, and the like illustrated in each embodiment may be combined or modified for other embodiments by a person having ordinary knowledge in the field to which the embodiments belong. Therefore, contents related to such combinations and modifications should be construed as being included in the scope of the embodiments.

Although the embodiments have been described above, these are only examples and are not intended to limit the embodiments, and those of ordinary skill in the field to which the embodiments belong are not departing from the essential characteristics of the present embodiment. It will be seen that branch transformation and application are possible. For example, each component specifically shown in the embodiment can be modified and implemented. And differences related to these modifications and applications should be construed as being included in the scope of the embodiments set in the appended claims.

Conductive support member 70, semiconductor reflective layer 55,
Second conductivity type semiconductor layer 116, active layer 114,
First conductivity type semiconductor layer 112, first electrode 81

Claims (7)

A conductive support member;
A semiconductor reflective layer on the conductive support member;
A first conductivity type semiconductor layer on the semiconductor reflective layer;
An active layer on the first conductivity type semiconductor layer;
A second conductivity type semiconductor layer on the active layer;
Includes; a first electrode on the second conductivity type semiconductor layer,
The semiconductor reflective layer includes a central portion overlapping the first electrode and the top and bottom, and an outer portion that does not overlap the first electrode and the top and bottom,
The semiconductor reflective layer is a red light emitting device whose thickness decreases from the central portion toward the outer portion. The method of claim 1,
The upper surface of the semiconductor reflective layer is a flat surface,
A red light emitting device having a lower thickness of the semiconductor reflective layer. The method of claim 1,
A red light emitting device further comprising a metal layer between the outer portion of the semiconductor reflective layer and the conductive support member. A conductive support member;
Metal reflective layer on the conductive support member:
A semiconductor reflective layer on the metal reflective layer;
A first conductivity type semiconductor layer on the semiconductor reflective layer;
An active layer on the first conductivity type semiconductor layer;
A second conductivity type semiconductor layer on the active layer;
Includes; a first electrode on the second conductivity type semiconductor layer,
The semiconductor reflective layer includes a central portion overlapping the first electrode and the top and bottom, and an outer portion that does not overlap the first electrode and the top and bottom,
The semiconductor reflective layer is a red light emitting device whose thickness decreases from the central portion toward the outer portion. delete The method of claim 4,
The metal reflective layer
A red light emitting device having a curved surface at an outer portion of the semiconductor reflective layer. An illumination system comprising a light-emitting unit comprising the red light-emitting element according to any one of claims 1 to 4 and 6.

Images