KR20160112372A - Uv light emitting device and lighting system - Google Patents

Abstract

An embodiment relates to a UV light emitting device, a manufacturing method of the light emitting device, a light emitting package, and a lighting system. The UV light emitting device of the embodiment includes: a second conductive-type AlGaN-based first semiconductor layer (116); an active layer (114) which includes a quantum well (114W) and a quantum wall (114B) and is placed on the second conductive-type AlGaN-based first semiconductor layer (116); and a first conductive-type AlGaN-based semiconductor layer (113) which is placed on the active layer (114). The quantum well (114W) includes an Al_xIn_yGa_(1-x-y)N layer (0<=x<=1, 0<=y<=1), and the quantum wall (114B) includes an Al_pIn_qGa_(1-p-q)N layer (0<=p<=1, 0<=q<=1). The band gap energy of the quantum wall (114B) gradually increases in a direction from the first conductive-type AlGaN-based semiconductor layer (113) to the second conductive-type AlGaN-based first semiconductor layer (116).

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a UV light emitting device,

Embodiments relate to a light emitting device, a method of manufacturing a light emitting device, a light emitting device package, and an illumination system.

A light emitting device can be formed by combining a group III-V element or a group II-VI element in the periodic table with a pn junction diode in which electrical energy is converted into light energy, Various colors can be realized by adjusting.

For example, nitride semiconductors have received great interest in the development of optical devices and high power electronic devices due to their high thermal stability and wide bandgap energy. Particularly, ultraviolet (UV) light emitting elements, blue light emitting elements, green light emitting elements, and red light emitting elements using nitride semiconductors are commercially available and widely used.

For example, in the case of an ultraviolet light emitting element (UV LED), a light emitting element that emits light distributed in a wavelength range of 200 nm to 400 nm is used for sterilizing and purifying in the above wavelength range and short wavelength, Or a hardener.

For example, a near UV LED is used in a counterfeit detection, resin curing, ultraviolet treatment or the like, and is also used in an illumination device that combines with a phosphor to realize visible light of various colors.

On the other hand, the ultraviolet light-emitting device has a problem that the light-receiving efficiency and the light output are lower than that of the blue light-emitting device. This serves as a barrier to practical use of the ultraviolet light emitting element.

For example, the Group-III nitride used in an ultraviolet light-emitting device can be widely used from visible light to ultraviolet light, but the efficiency of ultraviolet light compared to visible light is inferior. The reason is that Group III nitride absorbs ultraviolet rays toward the wavelength of ultraviolet rays and degradation of internal quantum efficiency due to low crystallinity.

Accordingly, in order to prevent the ultraviolet absorption in the Group-III nitride, the growth substrate, the GaN layer, the AlGaN layer, the active layer and the like are successively grown, and then the GaN layer capable of absorbing ultraviolet rays is removed and the AlGaN layer is exposed However, the problem of lowering the internal quantum efficiency due to the low crystallinity of the AlGaN layer is difficult to solve.

For example, according to the prior art, a tensile stress is generated in the AlGaN layer due to a mutual lattice constant difference in the growth of an AlGaN layer in a GaN layer, so that a crack is generated, there is a problem.

In addition, in the conventional ultraviolet light emitting device, when an InGaN material is used for a quantum well (Qw) to form an about 365 nm UV LED, the In composition should be less than about 1% to set the bandgap energy to about 365 nm have.

However, since the composition of In is very small, less than about 1% in the quantum well, the localization effect can hardly be seen. As a result, non-radiative recombination due to the expansion dislocation occurs This lowers the internal quantum efficiency (IQE) and can cause optical loss.

Also, according to the related art, a light extraction structure by texturing is formed. It is difficult to form an AlGaN layer thicker due to a difference in lattice constant during growth of an AlGaN layer in the GaN layer. Accordingly, the AlGaN layer exposed after the removal of the GaN layer is subjected to texturing It is difficult to form the light extracting structure by the light extraction efficiency.

Embodiments provide an ultraviolet light-emitting device having improved brightness, a method of manufacturing a light-emitting device, a light-emitting device package, and an illumination system.

Embodiments provide an ultraviolet light emitting device capable of improving internal quantum efficiency, a method of manufacturing a light emitting device, a light emitting device package, and an illumination system.

Also, embodiments of the present invention provide an ultraviolet light emitting device having improved light extraction efficiency, a method of manufacturing a light emitting device, a light emitting device package, and an illumination system.

The ultraviolet light-emitting device according to the embodiment includes a first conductive type AlGaN semiconductor layer 116; An active layer 114 disposed on the second conductive AlGaN first semiconductor layer 116 including a quantum well 114W and a quantum wall 114B; And a first conductive AlGaN-based semiconductor layer (113) disposed on the active layer (114).

The quantum well 114W includes an Al _x In _y Ga ₁ -xy N layer (where 0? _{X? 1} , 0? _Y? 1), and the quantum wall 114B includes Al _p In _q Ga _{1- pq} N layer (where 0? p? 1, 0? q? 1).

The band gap energy of the quantum wall 114B may gradually increase from the first conductive AlGaN-based semiconductor layer 113 toward the second conductive AlGaN-based first semiconductor layer 116. [

An illumination system according to an embodiment may include an illumination unit having the light emitting element.

Embodiments can provide an ultraviolet light emitting device, a method of manufacturing a light emitting device, a light emitting device package, and an illumination system in which the luminous intensity is improved according to the improvement of crystal quality of the epi layer.

Also, the embodiment can provide an ultraviolet light emitting device, a method of manufacturing a light emitting device, a light emitting device package, and an illumination system, wherein an In local effect is obtained by varying a composition of In in a quantum well and a quantum wall, have.

Also, the embodiments can provide an ultraviolet light emitting device, a method of manufacturing a light emitting device, a light emitting device package, and an illumination system with remarkably improved light extraction efficiency.

1 is a cross-sectional view of an ultraviolet light-emitting device according to a first embodiment;
2 is a partial example of an energy band diagram of an ultraviolet light-emitting device according to an embodiment.
FIG. 3 is a graph showing a relative luminous intensity change rate according to an increase in In composition in the active layer in the light emitting device according to the embodiment.
5 to 15 are cross-sectional views illustrating a method of manufacturing a light emitting device according to an embodiment.
16 is a cross-sectional view of a light emitting device package according to an embodiment.
17 is a perspective view of a lighting apparatus according to an embodiment.

In the description of the embodiments, each layer (film), region, pattern or structure is referred to as being "on" or "under" the substrate, each layer (film) Quot; on "and" under "are intended to include both" directly "or" indirectly " do. Also, the criteria for top, bottom, or bottom of each layer will be described with reference to the drawings.

(Example)

1 is a sectional view of an ultraviolet light-emitting device 100 according to the first embodiment.

The ultraviolet light emitting device 100 according to the embodiment includes the second conductive AlGaN first semiconductor layer 116, the quantum well 114W and the quantum wall 114B, and the second conductive AlGaN first semiconductor An active layer 114 disposed on the active layer 114 and a first conductive AlGaN-based semiconductor layer 113 disposed on the active layer 114.

The active layer 114 and the first conductive AlGaN-based semiconductor layer 113 may constitute the light emitting structure 110. In this case, the light emitting structure 110 may be formed of the second conductive AlGaN-based first semiconductor layer 116,

The embodiment can be applied to a vertical type ultraviolet light emitting device. For example, the light emitting structure 110 is disposed on the second electrode layer 120, and the first electrode 131 is formed on the first conductive AlGaN-based semiconductor layer 113 through the light-transmitting electrode layer 132, Can be arranged.

The transmissive electrode layer 132 may be formed of indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (ZnO), IGZO (In-Ga ZnO), or the like, in addition to the above-mentioned ZnO, ZnO, AZO, ATO, GZO, IZON, And is not limited to such a material.

_(1-xy) N (0? _{X ? 1, 0? Y ? 1)} disposed between the active layer 114 and the second conductive AlGaN-based first semiconductor layer 116, ) -Type semiconductor layer 115, as shown in FIG. The Al _x In _y Ga _(1-xy) N (0? _{X ? 1, 0? Y ? 1)} -type semiconductor layer 115 may function as an electron blocking layer, but is not limited thereto.

The second electrode layer 120 may include a contact layer 122, a reflective layer 124, and a conductive support member 126, but is not limited thereto.

Meanwhile, the ultraviolet light emitting device according to the embodiment may be applied to a horizontal ultraviolet light emitting device.

2 is a partial view of an energy band diagram of an ultraviolet light emitting device according to an embodiment.

The quantum well 114W constituting the active layer 114 in the embodiment may include an Al _x In _y Ga _1-xy N layer (where 0? _{X? 1} , 0? _Y? 1) Layer 114B may include an Al _p In _q Ga _1-pq N layer (where _{0? P? 1, 0? Q? 1} ).

The embodiment is characterized in that in the quantum wall 114B, a last quantum wall 114BL closest to the second conductive AlGaN-based first semiconductor layer 116 and a second quantum well 114Gb which is the closest to the second conductive AlGaN-based first semiconductor layer 116 and a nearest last quantum well 114WL.

The embodiment includes the first quantum wall 114B1 and the second quantum wall 114B1 sequentially arranged in the quantum wall 114B from the last quantum wall 114BL toward the first conductive AlGaN-based semiconductor layer 113, ).

An embodiment may include the first quantum well 114W1 adjacent to the last quantum well 114WL in the quantum well 114W.

Embodiments provide an ultraviolet light emitting device capable of improving internal quantum efficiency, a method of manufacturing a light emitting device, a light emitting device package, and an illumination system.

For this, the band gap energy of the quantum wall 114B may gradually increase from the first conductive AlGaN-based semiconductor layer 113 toward the second conductive AlGaN-based first semiconductor layer 116 .

For example, the band gap energy B2 of the second quantum wall 114B2 may be greater than the band gap energy B1 of the second quantum wall 114B2. The band gap energy B3 of the last quantum wall 114BL may be greater than the band gap energy B1 of the second quantum wall 114B2.

The composition p of Al of the quantum wall 114B may be larger than the composition x of Al of the quantum well 114W and the composition q of In of the quantum wall 114B may be larger than the composition (Y) of In of the quantum well 114W.

Further, according to the embodiment, the composition of In in the last quantum wall 114BL may be higher than the composition of In in the other quantum wall.

Further, according to the embodiment, the composition of In in the last quantum well 114WL may be higher than the composition of In in the other quantum well.

In the embodiment, the composition of Al in the last quantum well 114WL may be higher than the composition of Al in other quantum wells.

In addition, in the embodiment, the composition of Al in the last quantum wall 114BL may be higher than the composition of Al in the other quantum wall.

In addition, according to the embodiment, In and Al may have the largest composition as compared to quantum wells and quantum wells in the last quantum well 114WL and the last quantum wall 114BL.

Accordingly, the band gap energy of the quantum well 114W may gradually decrease from the first conductive AlGaN-based semiconductor layer 113 toward the second conductive AlGaN-based first semiconductor layer 116.

For example, the band gap energy W2 of the last quantum well 114WL may be smaller than the band gap energy W1 of the first quantum well 114W1.

According to the embodiment, when the active layer is formed, the In and Al compositions are gradually changed in the direction from the first conductive AlGaN-based semiconductor layer 113 toward the second conductive AlGaN-based first semiconductor layer 116 to grow most recombination The In quantization efficiency can be maximized by maximizing the In localization effect in the first quantum well 114W1 and the last quantum well 114WL.

In addition, according to the embodiment, the lattice constant difference between the quantum well 114W and the quantum wall 114B is reduced to improve the piezoelectric field, thereby increasing the possibility of recombining light, thereby enhancing the internal luminous efficiency.

According to the embodiment, when the bandgap energy Eg and the lattice constant difference are considered, the composition of Al in the quantum well 114W may be about 2% to about 4%, and the composition of In may be about 1.5% to about 2.5%.

Also, the predetermined amount of Al in the quantum wall 114B may be about 18% to about 21%, and the composition of In may be about 2% to about 4%.

According to the embodiment, when In and Al sequentially increase in Al and In as the quantum well 114W / quantum wall 114B pair proceeds, the In localization effect is maximized while minimizing the lattice constant difference, It can be more effective in improving the quantum efficiency.

According to the embodiment, the band gap energy Eg difference between the last quantum well 114WL and the last quantum wall 114BL may be about 0.2 eV to about 0.24 eV. If the difference is less than 0.2 eV, the carrier confinement may be weak, and if it is more than 0.24 eV, hole injection may be affected.

In an embodiment, the thickness of the quantum well 114W may be from about 3 nm to about 10 nm, and the thickness of the quantum wall 114B may be from about 3 nm to about 15 nm.

According to the embodiment, other quantum wall 114B except for the last quantum wall 114BL can be doped with Si.

VF3 (at 500mA) Po (at 500mA) Wavelength (at 500mA) Comparative Example 3.72 598.2 369.0 Experimental Example 3.79 619.5 368.0

Table 1 shows characteristic data of Comparative Examples and Experimental Examples.

In the comparative example, the composition of the quantum well is In _0.01 Ga _0.99 N, the composition of the quantum wall is Al _0.12 Ga _0.88 N, the band gap energy difference (Eg) between the quantum well and the quantum well is about 0.219 eV, Was -0.013.

In the experimental example, the composition of the last quantum well 114WL is Al _0.03 In _0.02 Ga _0.95 N, the composition of the last quantum wall 114BL is Al _0.195 In _0.03 Ga _0.775 N, and the last quantum well 114WL and the last quantum wall 114BL) was 0.219 eV, and the difference in lattice constant was about -0.009.

Therefore, according to the embodiment, the difference in lattice constant is remarkably reduced, thereby reducing the Piezo effect and improving the QCSE, so that the brightness can be greatly improved.

In the embodiment, the composition of the last quantum well 114WL is Al _0.03 In _0.02 Ga _0.95 N, and the composition of In is higher by 1% (0.01) than that of the quantum well of the In _0.01 Ga _0.99 N composition of the comparative example.

That is, according to the embodiment, the In localization effect can be advantageous and the internal quantum efficiency (IQE) can be advantageously improved by increasing the radiative recombination.

FIG. 3 is a graph showing a relative change rate of relative light according to the increase of the In composition in the active layer in the light emitting device according to the embodiment.

This is also confirmed by the fact that the luminous intensity Po is remarkably increased by about 20 mW as the quantum well 114W in which the composition of In is gradually increased as shown in Table 1. [ For example, when the In concentration is about 1% in the quantum well 114W, the relative luminous intensity is about 93. When the In concentration is increased to about 2%, the relative luminous intensity is remarkably increased to about 100.

In addition, according to the embodiment, since the band gap energy Eg of the remaining quantum well is higher than that of the last quantum well 114WL in which most light is emitted, light absorption by other quantum wells may be less likely.

4 is a sectional view of the ultraviolet light emitting device 102 according to the second embodiment.

The second embodiment can employ the technical features of the first embodiment, and the main features of the second embodiment will be mainly described below.

The second embodiment intends to provide an ultraviolet light emitting device having improved brightness in accordance with the improvement of crystal quality of an epi layer.

According to the prior art, tensile stress is generated in the AlGaN layer due to the difference in lattice constant during the growth of the AlGaN layer in the GaN layer and cracks are generated. As a result, there is a problem that the crystal quality is lowered and the lightness is lowered. .

Further, according to the prior art, as the AlGaN layer is grown, the tensile stress becomes stronger due to accumulation of the lattice constant difference. For example, when the AlGaN layer is grown to about 2.5 탆 or more when the Al% is about 5% in the AlGa layer, it is difficult to grow the AlGaN layer at a thickness of 2.5 탆 or more because the crack grows exponentially. Resulting in a decrease in yield and optical characteristics.

In addition, the embodiment is intended to provide an ultraviolet light emitting device in which light extraction efficiency is remarkably improved.

In the conventional light emitting device, a light extraction structure is formed by forming texturing through an etching process when a chip is manufactured. In the conventional technology, since the AlGaN layer can not be formed thick, There is a problem that the active layer is damaged in the etching process for forming the light extraction structure, or the electrical reliability of the light emitting device chip is deteriorated according to the damage of the active layer even if it is formed.

4, the light emitting device 100 according to the second embodiment includes a second conductive AlGaN-based first semiconductor layer 116 and an active layer (not shown) on the second conductive AlGaN-based first semiconductor layer 116 A first conductive AlGaN-based semiconductor layer 113 on the active layer 114 and a first AlGaN-based light extracting pattern having a reduced horizontal width on the first conductive AlGaN-based semiconductor layer 113 P1).

A second electrode layer 120 including a contact layer 122, a reflective layer 124 and a conductive support member 126 may be disposed under the light emitting structure 110. The first conductive AlGaN-based semiconductor layer 113 may include a first electrode 131 and may be a vertically-structured light emitting device chip, but the present invention is not limited thereto.

In the embodiment, the first AlGaN-based light extracting pattern P1 may be formed of the same material as the first conductive AlGaN-based semiconductor layer 113.

In the embodiment, the thickness D1 of the first conductive AlGaN-based semiconductor layer 113 is about 2.5 μm or more, so that the first AlGaN-based light extracting pattern P1 is stably provided, thereby increasing the light extraction efficiency.

For example, the thickness D1 of the first conductive AlGaN-based semiconductor layer 113 is about 2.5 μm to 5.0 μm, and is secured with high quality without cracking, thereby improving the luminous efficiency, The first AlGaN-based light extracting pattern P1 can be provided without an electrical short, and the light extraction efficiency can be remarkably improved.

In addition, the embodiment can further improve the light extraction efficiency by further including an AlGaN-based second light extracting pattern P2 on the upper surface of the first conductive AlGaN-based semiconductor layer 113.

5, a high composition AlGaN-based stress relieving layer 118 is inserted to suppress the occurrence of cracks in the first conductive AlGaN-based semiconductor layer 113, The cracks generated by the insertion of the AlGaN-based stress relieving layer 118 are buried by the GaN-based pattern 119 so that the first low-composition first Since the conductive AlGaN-based semiconductor layer 113 is not a tensile stress but rather a compressive stress, the generation of cracks can be remarkably suppressed.

If cracks are not generated in the first conductive AlGaN-based semiconductor layer 113, the first conductive AlGaN-based semiconductor layer 113 can be grown to a thickness of more than 2.5 μm, thereby enabling a light extraction pattern forming process to improve reliability while improving light extraction efficiency.

Hereinafter, a method of manufacturing an ultraviolet light emitting device according to an embodiment will be described with reference to FIGS. 5 to 14. FIG. Hereinafter, the second embodiment will be described as a reference, but the manufacturing method of the embodiment is not limited thereto.

First, the substrate 105 is prepared as shown in Fig. The substrate 105 may be formed of a material having excellent thermal conductivity, and may be a conductive substrate or an insulating substrate. For example, the substrate 105 may include at least one of sapphire (Al ₂ O ₃ ), SiC, Si, GaAs, GaN, ZnO, GaP, InP, Ge, and Ga ₂ O ₃ . A concavo-convex structure may be formed on the substrate 105, but the present invention is not limited thereto.

A buffer layer (not shown) may be formed on the substrate 105. The buffer layer may mitigate the lattice mismatch between the material of the light emitting structure 110 and the substrate 105, and the material of the buffer layer may be a group III-V group or a group II-VI compound semiconductor such as GaN, InN , AlN, InGaN, AlGaN, InAlGaN, and AlInN.

Next, a first conductive semiconductor layer 112 may be formed on the first substrate 105. For example, the first conductive semiconductor layer 112 may be formed of a compound semiconductor such as a group III-V element, a group II-VI element, or the like, and the first conductive type dopant may be doped.

When the first conductive semiconductor layer 112 is an n-type semiconductor layer, the first conductive dopant may include Si, Ge, Sn, Se, and Te as an n-type dopant.

The first conductive semiconductor layer 112 includes a semiconductor material having a composition formula of In _x Al _y Ga _1-xy N (0? X? 1, 0? _Y? 1, 0? _X + y? 1) . For example, the first conductive semiconductor layer 112 may be formed of one or more of GaN, InN, AlN, InGaN, AlGaN, InAlGaN, AlInN, AlGaAs, InGaAs, AlInGaAs, GaP, AlGaP, InGaP, AlInGaP, .

Next, a first AlGaN-based stress relaxation layer 118a may be formed on the first conductive type semiconductor layer 112. FIG. Thereafter, the second AlGaN-based stress relieving layer 118b may be formed on the first AlGaN-based stress relieving layer 118a to form the AlGaN-based stress relieving layer 118.

According to the embodiment, a high composition AlGaN series stress relieving layer 118 is inserted to suppress the occurrence of cracks in the first conductive AlGaN-based semiconductor layer 113 to be formed later, And the cracks generated by the insertion of the AlGaN-based stress relieving layer 118 are filled with the GaN pattern 119 to form a first low-composition first layer -Type AlGaN-based semiconductor layer 113 is not a tensile stress but rather a compressive stress, so that occurrence of cracks can be significantly suppressed.

Accordingly, if cracks are not generated in the first conductive AlGaN-based semiconductor layer 113, the first conductive AlGaN-based semiconductor layer 113 can be grown to a thickness of more than 2.5 μm, thereby enabling a light extraction pattern forming process, have.

The first conductive AlGaN-based semiconductor layer 113 can be formed by forming the GaN-based pattern 119 on the AlGaN-based stress relaxation layer 118 as shown in FIG.

Hereinafter, the mechanism by which cracks do not occur in the first conductive AlGaN-based semiconductor layer 113 will be described in more detail.

According to the embodiment, the AlGaN-based stress relaxation layer 118 having a higher Al composition than the first conductive AlGaN-based semiconductor layer 113 is inserted to generate misfit dislocations in the 11-20 direction, The first conductive AlGaN-based semiconductor layer 113 is grown by filling the crack caused by the insertion of the AlGaN-based stress relieving layer 118 by the GaN-based pattern 119 grown in 3D mode, It is possible to suppress the generation of cracks at the same time and to improve the crystal quality.

Cracks generated by the AlGaN-based stress relaxation layer 118 having a higher Al composition are partially buried by the GaN pattern 119, for example, GaN island patterns, The first conductive AlGaN-based semiconductor layer 113, which has a low lattice constant and is thickly grown thereafter since it is a high AlGaN-based stress relaxation layer 118 region, is not a tensile stress but rather a compressive stress Compressive Stress), cracks in the first conductive AlGaN-based semiconductor layer 113 can be suppressed.

In the embodiment, the AlGaN-based stress relaxation layer 118 may be one layer or a plurality of layers. On the other hand, in the embodiment, the first conductive AlGaN-based semiconductor layer 113 after the AlGaN-based stress relaxation layer 118 disposed on the uppermost side may be at least 1.5 탆 or more. Thus, the thickness of the entire first conductive AlGaN-based semiconductor layer 113 can be ensured to be not less than 2.5 μm.

In the embodiment, when the ultraviolet light emitting device is about 365 nm UVLED, the Al composition x of the first conductive AlGaN-based semiconductor layer 113 may be about 2% to 8%, but is not limited thereto.

In the embodiment, the AlGaN-based stress relaxation layer 118 may include a first AlGaN-based stress relaxation layer 118a and a second AlGaN-based stress relaxation layer 118b.

The AlGaN-based stress relaxation layer 118 may have an Al composition (y) of nAl _y GaN (x <y <0.5). Further, the Al composition (y) of the AlGaN-based stress relaxation layer 118 may be more effective when it is about 0.25 to 0.35, but is not limited thereto.

When the Al composition y of the AlGaN-based stress relaxation layer 118 is smaller than the composition x of Al of the first conductive AlGaN-based semiconductor layer 113, cracks are not generated in a large amount and stress relaxation Stress relief, and there is a possibility that a tensile stress is continuously applied to the first conductive AlGaN-based semiconductor layer 113 grown thereafter to cause cracks.

When the Al composition (y) of the AlGaN-based stress relaxation layer 118 is 0.50 or more, a large amount of cracks and misfit dislocations are generated due to the difference in lattice constant, which may be bad for quality.

In the embodiment, the thickness of the AlGaN-based stress relaxation layer 118 may be 50 to 200 nm, and may be more effective when the thickness is 80 to 120 nm.

When the thickness of the AlGaN-based stress relaxation layer 118 is less than 50 nm, tensile stress is not sufficiently generated, and cracks and misspot potentials may not be generated. When the thickness of the AlGaN series stress relieving layer 118 is thicker than 200 nm, Cracks and misfit dislocations may occur and the quality may deteriorate.

Next, the GaN sequence pattern 119 will be described with reference to FIG.

The GaN-based pattern 119 may include an undoped GaN-based pattern or a first-conductivity-based GaN-based pattern.

The GaN pattern 119 may be grown in 3D mode. For example, grows on the Facet surface of the second AlGaN-based stress relaxation layer 118b, so that the crack can be filled.

The GaN-based pattern 119 may be grown at a temperature of about 700 ° C. to about 1100 ° C. in order to grow facets, that is, to grow in 3D mode.

On the other hand, if the growth is carried out at a low temperature of about 700 ° C. to 800 ° C., the quality may be poor. Therefore, if the growth is performed at a temperature of about 900 ° C. to 1100 ° C. and a high pressure of about 400 mbar to 500 mbar, .

On the other hand, if V / Ⅲ is high, 2D mode is strengthened and when it is low, 3D mode is strengthened. Because it depends on V / Ⅲ Reactor type, optimum condition for each equipment should be found.

For example, the temperature is about 900 ° C to 1100 ° C, and the pressure is in the range of 400 mbar to 500 mbar.

The thickness of the GaN-based pattern 119 may be about 10 nm to 50 nm, and more preferably about 20 nm to 30 nm.

If the thickness of the GaN pattern 119 is less than 10 nm, it is difficult to effectively fill the crack. If the thickness exceeds 50 nm, light loss due to light absorption in the GaN pattern 119 may occur.

When the GaN pattern 119 is an undoped GaN pattern, a current spreading effect can be seen. If the GaN-based pattern 119 remains, the first electrode formed later overlaps with the upper and lower portions, thereby further increasing the current diffusion effect.

When the GaN-based pattern 119 includes the first conductivity type GaN-based pattern, the concentration of the n-type dopant may be more than 0 to 1.0x10 ²⁰ , and the current injection efficiency may be increased by doping the n-type dopant .

Next, as shown in FIG. 7, the active layer 114 may be formed on the first conductive AlGaN-based semiconductor layer 113.

The active layer 114 may be formed of at least one of a single quantum well structure, a multi quantum well (MQW) structure, a quantum-wire structure, or a quantum dot structure.

For example, the active layer 114 may be formed with a multiple quantum well structure by injecting trimethyl gallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and trimethyl indium gas (TMIn) But is not limited thereto.

The active layer 114 may include a quantum well and a quantum wall. For example, the active layer 114 may include one or more of a pair structure of AlGaN / GaN, AlGaN / AlGaN, InGaN / InGaN, InAlGaN / GaN, GaAs / AlGaAs, InGaAs / AlGaAs, GaP / AlGaP, But the present invention is not limited thereto.

Hereinafter, the technical characteristics of the active layer 114 of the embodiment will be described in more detail with reference to FIG.

The quantum well 114W constituting the active layer 114 in the embodiment may include an Al _x In _y Ga _1-xy N layer (where 0? _{X? 1} , 0? _Y? 1) Layer 114B may include an Al _p In _q Ga _1-pq N layer (where _{0? P? 1, 0? Q? 1} ).

The embodiment is characterized in that in the quantum wall 114B, a last quantum wall 114BL closest to the second conductive AlGaN-based first semiconductor layer 116 and a second quantum well 114Gb which is the closest to the second conductive AlGaN-based first semiconductor layer 116 and a nearest last quantum well 114WL.

The embodiment includes the first quantum wall 114B1 and the second quantum wall 114B1 sequentially arranged in the quantum wall 114B from the last quantum wall 114BL toward the first conductive AlGaN-based semiconductor layer 113, ).

An embodiment may include the first quantum well 114W1 adjacent to the last quantum well 114WL in the quantum well 114W.

The band gap energy of the quantum wall 114B may gradually increase from the first conductive AlGaN-based semiconductor layer 113 toward the second conductive AlGaN-based first semiconductor layer 116. In this case,

The composition p of Al of the quantum wall 114B may be larger than the composition x of Al of the quantum well 114W and the composition q of In of the quantum wall 114B may be larger than the composition (Y) of In of the quantum well 114W.

Further, according to the embodiment, the composition of In in the last quantum wall 114BL may be higher than the composition of In in the other quantum wall.

Further, according to the embodiment, the composition of In in the last quantum well 114WL may be higher than the composition of In in the other quantum well.

Accordingly, the band gap energy of the quantum well 114W may gradually decrease from the first conductive AlGaN-based semiconductor layer 113 toward the second conductive AlGaN-based first semiconductor layer 116.

According to the embodiment, when the active layer is formed, the In and Al compositions are gradually changed in the direction from the first conductive AlGaN-based semiconductor layer 113 toward the second conductive AlGaN-based first semiconductor layer 116 to grow most recombination The In quantization efficiency can be maximized by maximizing the In localization effect in the first quantum well 114W1 and the last quantum well 114WL.

In addition, according to the embodiment, the lattice constant difference between the quantum well 114W and the quantum wall 114B is reduced to improve the piezoelectric field, thereby increasing the possibility of recombining light, thereby enhancing the internal luminous efficiency.

According to the embodiment, In and Al may have the largest composition as compared with quantum wells and quantum wells in the last quantum well 114WL and the last quantum wall 114BL.

According to the embodiment, when the bandgap energy Eg and the lattice constant difference are considered, the composition of Al in the quantum well 114W may be about 2% to about 4%, and the composition of In may be about 1.5% to about 2.5%.

Also, the predetermined amount of Al in the quantum wall 114B may be about 18% to about 21%, and the composition of In may be about 2% to about 4%.

According to the embodiment, when In and Al sequentially increase in Al and In as the quantum well 114W / quantum wall 114B pair proceeds, the In localization effect is maximized while minimizing the lattice constant difference, It can be more effective in improving the quantum efficiency.

According to the embodiment, the band gap energy Eg difference between the last quantum well 114WL and the last quantum wall 114BL may be about 0.2 eV to about 0.24 eV. If the difference is less than 0.2 eV, it may be vulnerable to carrier confinement. If the difference is more than 0.24 eV, hole injection may be affected.

In an embodiment, the thickness of the quantum well 114W may be from about 3 nm to about 10 nm, and the thickness of the quantum wall 114B may be from about 3 nm to about 15 nm.

According to the embodiment, the difference in lattice constant is remarkably reduced, thereby reducing the Piezo electric effect and improving the QCSE, so that the light intensity can be greatly improved.

Also, in the embodiment, the composition of the last quantum well 114WL may be Al _0.03 In _0.02 Ga _0.95 N, and the composition of the quantum well of the comparative example may be In _0.01 Ga _0.99 N. At this time, the composition of the quantum well of the example is 1% (0.01) higher than that of the quantum well of the comparative example.

That is, according to the embodiment, the In localization effect can be advantageous and the internal quantum efficiency (IQE) can be advantageously improved by increasing the radiative recombination.

For example, as shown in FIG. 3, a difference in composition of about 1% In shows a large difference in luminous intensity. As shown in Table 1, when the quantum well 114W in which the composition of In is gradually increased, the luminous intensity Po is about 20 mW It is also confirmed through a significant rise.

In addition, according to the embodiment, since the band gap energy Eg of the remaining quantum well is higher than that of the last quantum well 114WL in which most light is emitted, light absorption by other quantum wells may be less likely.

Next, referring to FIG. 8, the second conductive AlGaN-based first semiconductor layer 116 may be formed of a compound semiconductor such as a semiconductor compound, for example, a Group III-V, a Group II-VI, , A second conductivity type dopant may be doped.

For example, may include a semiconductor material having the second conductivity type AlGaN-based composition formula of the first semiconductor layer _{(116) Al q Ga 1-} q N (0≤q≤1). When the second conductive AlGaN-based first semiconductor layer 116 is a p-type semiconductor layer, the second conductive-type dopant may include Mg, Zn, Ca, Sr, and Ba as p-type dopants.

The first conductive AlGaN-based semiconductor layer 113 may be an n-type semiconductor layer and the second conductive AlGaN-based first semiconductor layer 116 may be a p-type semiconductor layer, but the present invention is not limited thereto.

On the first conductive semiconductor layer 116 of the second conductivity type, a semiconductor layer (not shown) having a polarity opposite to that of the second conductive type may be formed. Accordingly, the light emitting structure 110 may have 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.

Next, as shown in FIG. 9, a second electrode layer 120 may be formed on the second conductive AlGaN-based first semiconductor layer 116. The second electrode layer 120 may include a contact layer 122, a reflective layer 124, and a conductive support member 126.

The contact layer 122 may be formed by laminating a single metal, a metal alloy, a metal oxide, or the like so as to efficiently perform carrier injection. For example, the contact layer 122 may be formed of a superior material that is in electrical contact with the semiconductor.

For example, the contact layer 122 may include at least one of ITO (indium tin oxide), IZO (indium zinc oxide), IZTO (indium zinc tin oxide), IAZO (indium aluminum zinc oxide), IGZO (ZnO), indium gallium tin oxide (AZO), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), IZON nitride, AGZO Ag, Ni, Cr, Ti, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Ni, IrOx / Au, and Ni / IrOx / , Au, and Hf, and is not limited to such a material.

A reflective layer 124 may be formed on the contact layer 122. The reflective layer 124 may be formed of a material excellent in reflectivity and excellent in electrical contact. For example, the reflective layer 124 may be formed of a metal or an alloy including at least one of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au and Hf.

The reflective layer 124 may be formed of a multilayer structure using a metal or an alloy and a light transmitting conductive material such as IZO, IZTO, IAZO, IGZO, IGTO, AZO, or ATO. For example, IZO / Ni, AZO / Ag, IZO / Ag / Ni, AZO / Ag / Ni, or the like.

Next, a conductive support member 126 may be formed on the reflective layer 124.

The conductive support member 126 may be formed of a metal, a metal alloy, or a conductive semiconductor material having excellent electrical conductivity so that carriers can be efficiently injected. For example, the conductive support member 126 may be formed of a material selected from the group consisting of Cu, Au, Cu Alloy, Ni-nickel, Cu- GaN, Si, Ge, GaAs, ZnO, SiGe, SiC, etc.).

The conductive support member 126 may be formed using an electrochemical metal deposition method, a bonding method using a yttetic metal, or the like.

Next, the substrate 105 may be removed from the light emitting structure 110 as shown in FIG. For example, the substrate 105 may be removed by using a high-power laser to separate the substrate or use a chemical etching method. In addition, the substrate 105 may be removed by physically grinding.

For example, in the laser lift-off method, energy is absorbed at the interface between the substrate 105 and the light emitting structure when a predetermined energy is applied at room temperature, and the bonding surface of the light emitting structure is thermally decomposed to separate the substrate 105 from the light emitting structure can do.

Next, as shown in FIG. 11, the AlGaN-based stress relaxation layer 118 may be exposed by removing the first conductivity type semiconductor layer 112 by wet etching or dry etching.

Next, as shown in FIG. 12, the AlGaN-based stress relieving layer 118 and the GaN-based pattern 119 may be sequentially or simultaneously removed by wet etching or dry etching to expose the first conductive AlGaN-based semiconductor layer 113 have.

Accordingly, a first AlGaN-based light extracting pattern P1 may be formed on the first conductive AlGaN-based semiconductor layer 113, and the first AlGaN-based light extracting pattern P1 may be a regular pattern or an irregular pattern Or a mixture thereof.

In one embodiment, the first AlGaN-based light extracting pattern P1 has a predetermined horizontal width on the first conductive AlGaN-based semiconductor layer 113, and the first conductive AlGaN-based semiconductor layer 113 and the first conductive AlGaN- And may be formed of the same material.

According to the embodiment, as the horizontal width of the first AlGaN-based light extracting pattern 121 gradually decreases, the light extraction surface area can be widened, and the possibility of light extraction to the outside can be increased to improve the light extraction efficiency .

The thickness of the first conductive AlGaN-based semiconductor layer 113 excluding the height of the first AlGaN-based light extracting pattern P1 is set to be 1.5 탆 or more, for example, 2.5 탆 to 5.0 탆, So that the electrical reliability of the light emitting device chip may not be affected.

Next, as shown in FIG. 13, a second AlGaN-based light extracting pattern P2 may be formed between the first AlGaN-based light extracting patterns P1.

The second AlGaN-based light extracting pattern P2 may be formed on the side surface and the upper surface of the first AlGaN-based light extracting pattern P1, but is not limited thereto.

Thus, the light extracting efficiency can be further improved by the operation of the complex light extracting mechanism through the first AlGaN-based light extracting pattern P1 having a larger size and the second AlGaN-based light extracting pattern P2 having a smaller size have.

Next, as shown in FIG. 14, a first electrode 131 may be formed on the first conductive AlGaN-based semiconductor layer 113. The first electrode 131 may be formed of a metal or an alloy including at least one of Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au and Hf.

Thus, the ultraviolet light emitting device according to the embodiment can be manufactured.

Ultraviolet light-emitting devices are divided into UV-A (315 to 400 nm), UV-B (280 to 315 nm) and UV-C (200 to 280 nm) in the long wavelength order.

The UV-A (315-400 nm) region of the UV-LED according to the embodiment can be used for industrial UV curing, printing ink curing, exposure apparatus, counterfeit discrimination, photocatalytic disinfection, special illumination (aquarium / UV-B (280 ~ 315nm) region can be used for medical use, and UV-C (200 ~ 280nm) region can be applied to air purification, water purification, sterilization products and the like.

A plurality of light emitting devices according to embodiments may be arrayed on a substrate in the form of a package, and a light guide plate, a prism sheet, a diffusion sheet, a fluorescent sheet, or the like 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, a pointing device, a lamp, a streetlight, a vehicle lighting device, a vehicle display device, a smart watch, but is not limited thereto.

For example, FIG. 15 is a view illustrating a light emitting device package 200 having a light emitting device according to the embodiments.

The light emitting device package according to the embodiment includes a package body 205, a third electrode layer 213 and a fourth electrode layer 214 provided on the package body 205, A light emitting device 100 electrically connected to the third electrode layer 213 and the fourth electrode layer 214 and a molding member 230 surrounding the light emitting device 100 are included.

The third electrode layer 213 and the fourth electrode layer 214 are electrically isolated from each other and provide power to the light emitting device 100. The third electrode layer 213 and the fourth electrode layer 214 may function to increase light efficiency by reflecting the light generated from the light emitting device 100, And may serve to discharge heat to the outside.

The light emitting device 100 may be electrically connected to the third electrode layer 213 and / or the fourth electrode layer 214 by a wire, flip chip, or die bonding method.

The light emitting device 100 may include the light emitting device 102 according to the second embodiment, the light emitting device 103 according to the third embodiment, or the like, although it may be an ultraviolet light emitting device according to the first embodiment. can do.

The molding member 230 may include a phosphor 232 to form a light emitting device package of white light, but the present invention is not limited thereto.

16 is an exploded perspective view of an illumination system according to an embodiment.

The lighting apparatus according to the embodiment may include a cover 2100, a light source module 2200, a heat discharger 2400, a power supply unit 2600, an inner case 2700, and a socket 2800. Further, the illumination 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 heat discharging body 2400 and has guide grooves 2310 through which the plurality of light source portions 2210 and the connector 2250 are inserted.

The holder 2500 blocks the receiving groove 2719 of the insulating portion 2710 of the inner case 2700. Therefore, the power supply unit 2600 housed in the insulating portion 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 2630, a base 2650, and an extension 2670. The inner case 2700 may include a molding part together with the power supply part 2600. The molding part is a hardened portion of the molding liquid so that the power supply unit 2600 can be fixed inside the inner case 2700.

The features, structures, effects and the like described in the embodiments 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 the embodiments can be combined and modified by other persons skilled in the art to which the embodiments belong. Accordingly, the contents of such combinations and modifications should be construed as being included in the scope of the embodiments.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention. It can be seen that the modification and application of branches are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that the present invention may be embodied in many other specific forms without departing from the spirit or essential characteristics thereof.

The second conductive type AlGaN-based first semiconductor layer 116, the quantum well 114W, the quantum wall 114B,
The active layer 114, the first conductive AlGaN-based semiconductor layer 113,

Claims (12)

A second conductive type AlGaN-based first semiconductor layer;
An active layer disposed on the second conductive type AlGaN-based first semiconductor layer including a quantum well and a quantum wall; And
And a first conductive AlGaN-based semiconductor layer disposed on the active layer,
Wherein the quantum well comprises an Al _x In _y Ga _1-xy N layer (0? _{X? 1} , 0? _Y? 1)
Wherein the quantum wall comprises an Al _p In _q Ga _1-pq N layer (where _{0? P? 1, 0? Q? 1} )
The band gap energy of the quantum wall is
Wherein the first conductive AlGaN-based semiconductor layer gradually increases in the direction of the first conductivity type AlGaN-based first semiconductor layer. The method according to claim 1,
The composition p of Al in the quantum well is larger than the composition x of Al in the quantum well,
(Q) of In in the quantum well is larger than a composition (y) of In of the quantum well. The method according to claim 1,
The band gap energy of the quantum well may be,
The first conductivity type AlGaN-based semiconductor layer gradually decreases in the direction of the first conductivity type AlGaN-based first semiconductor layer. The method according to claim 1,
Wherein,
A last quantum well closest to the second conductive type AlGaN first semiconductor layer in the quantum well and a last quantum well closest to the second conductivity type AlGaN first semiconductor layer in the quantum well,
And the composition of In in the last quantum wall is higher than that of In in the other quantum wall. 5. The method of claim 4,
And the composition of In in the last quantum well is higher than that of In in the other quantum well. 5. The method of claim 4,
And the band gap energy difference between the last quantum well and the last quantum well is 0.2 eV to 0.24 eV. 5. The method of claim 4,
And the composition of Al in the last quantum well is higher than that of Al in the other quantum well. 5. The method of claim 4,
And the composition of Al in the last quantum wall is higher than the composition of Al in the other quantum wall. The method according to claim 1,
And a first AlGaN-based light extraction pattern having a horizontal width reduced on the first conductive AlGaN-based semiconductor layer. 10. The method of claim 9,
The first AlGaN-based light extracting pattern
And the first conductive AlGaN-based semiconductor layer. 10. The method of claim 9,
And an AlGaN-based second light extracting pattern is formed on the upper surface of the first conductive AlGaN-based semiconductor layer. An illumination system comprising a light-emitting unit comprising a light-emitting element according to any one of claims 1 to 11.

Images