KR102250523B1 - Light emitting device and lighting system - Google Patents

Abstract

The light emitting device of the embodiment includes a first conductive type semiconductor layer having a rod shape; A reflective layer disposed to surround the first conductivity-type semiconductor layer; An active layer disposed to surround the reflective layer; And a second conductivity type semiconductor layer disposed to surround the active layer.

Description

Light emitting device and lighting system {LIGHT EMITTING DEVICE AND LIGHTING SYSTEM}

The embodiment relates to a light-emitting device, a method of manufacturing a light-emitting device, a light-emitting device package, and a lighting system, and more specifically, to a light-emitting device having a vertical rod-shaped semiconductor structure.

Light Emitting Device is a pn junction diode that converts electrical energy into light energy. It can be created as a compound semiconductor such as Group III and Group V on the periodic table. Various colors can be realized by controlling the composition ratio of the compound semiconductor. It is possible.

When the forward voltage is applied, the electrons in the n-layer and the holes in the p-layer are combined to emit energy equivalent to the band gap energy of the conduction band and the balance band. , This energy is mainly emitted in the form of heat or light, and when it is radiated in the form of light, it becomes a light-emitting device.

For example, 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, and an ultraviolet (UV) light emitting device using a nitride semiconductor have been commercialized and widely used.

As the demand for high-efficiency LEDs has recently increased, improvement in light intensity has become an issue.

In particular, in the case of a light-emitting structure that directly emits light, measures have been proposed to improve the luminous intensity through various structural changes by breaking away from the simple stacked epitaxial structure.

At this time, in the direction of improvement of the light emitting structure, the crystal quality of the semiconductor layer must be improved, the light emitting region must be expanded, and the generated light must be effectively emitted to the outside of the light emitting structure.

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

The light emitting device of the embodiment includes a first conductive type semiconductor layer having a rod shape; A reflective layer disposed to surround the first conductivity-type semiconductor layer; An active layer disposed to surround the reflective layer; And a second conductivity type semiconductor layer disposed to surround the active layer.

In another aspect, the light emitting device of the embodiment is a light emitting device including a light emitting structure having a horizontal rod shape, the light emitting structure is a first conductive type semiconductor layer having a rod shape, and on the first conductive type semiconductor layer. And a second conductive type semiconductor layer disposed on the active layer, and a reflective layer disposed between the first conductive type semiconductor layer and the active layer.

In addition, the lighting system according to the embodiment may include a light emitting module including the light emitting device.

According to the embodiment, a light emitting device having an optimal structure capable of increasing luminous intensity, a method of manufacturing a light emitting device, a light emitting device package, and a lighting system can be provided.

Compared to the stacked nano-rod structure, the light-emitting structure of the embodiment has the advantage that the surface area of the active layer in contact with the semiconductor layer is dramatically increased, so that the luminous efficiency can be greatly improved, and the area in which light can resonate is also increased.

In addition, when the light emitting structure is grown on the substrate, the area in contact with the substrate interface is small, so that the probability of occurrence of TDD is reduced, which is advantageous in improving the quality of the active layer.

In particular, in the light emitting structure of the embodiment, a reflective layer is disposed to reflect light emitted toward the first conductivity-type semiconductor layer, thereby reducing the light absorption rate of the first conductivity-type semiconductor layer, thereby improving light efficiency.

In addition, in the light emitting structure of the embodiment, when light is emitted from the active layer to the side of the light emitting structure, light extraction efficiency may be improved due to the angled shape on the side of the light emitting structure.

In addition, according to the embodiment, it is possible to provide a light emitting device having improved luminous efficiency, a method of manufacturing a light emitting device, a light emitting device package, and a lighting system by electronically coupling a hole and a hole across a plurality of quantum wells.

In addition, according to the embodiment, there is an advantage of improving the quality of the active layer to reduce the operating voltage and improve reliability and reproducibility.

In addition, according to the embodiment, a light emitting device capable of improving quantum confinement effect, improving luminous efficiency, and improving device reliability, a method of manufacturing a light emitting device, a light emitting device package, and a lighting system can be provided.

1 is a graph showing the relationship between the thickness of the remaining GaN layer and light efficiency.
2 is a plan view of the light emitting device according to the first embodiment, and FIG. 3 is a cross-sectional view of the light emitting device of FIG. 1.
4 is a perspective view of a light emitting structure according to the first embodiment.
5 is a perspective view of a light emitting structure according to a second embodiment.
6 is a cross-sectional view of a light emitting structure according to a third embodiment.
7 is a cross-sectional view of a light emitting structure according to a fourth embodiment.
8 is a side cross-sectional view showing a light emitting device according to the second embodiment.
9 is a side cross-sectional view showing a light emitting device according to the third embodiment.
10 to 16 are views illustrating a manufacturing process of the light emitting device of FIG. 2.
17 is a diagram illustrating a light emitting device package having the light emitting device of FIG. 2.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art may easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

Throughout the specification, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components unless specifically stated to the contrary. In the drawings, parts not related to the description are omitted in order to clearly describe the present invention, and similar reference numerals are attached to similar parts throughout the specification.

In the description of the embodiments, when a part such as a layer, a film, a region, a plate, etc. is said to be "on" another part, this includes not only the case where the other part is "directly above", but also the case where there is another part in the middle. Conversely, when one part is "directly above" another part, it means that there is no other part in the middle.

Recently, interest in light emitting devices that emit ultraviolet wavelength bands is increasing. In addition, semiconductor layers disposed around the active layer are generally configured to include GaN. However, since the energy band gap of GaN corresponds to the ultraviolet wavelength band, there is a problem that light in the ultraviolet wavelength band moving toward GaN is absorbed by the GaN layer.

1 is a graph showing the relationship between the thickness of the remaining GaN layer and light efficiency.

As can be seen from FIG. 1, it can be seen that the light efficiency sharply decreases as the thickness of GaN remaining in the vicinity of the active layer increases.

In order to prevent this, a method of removing GaN from a semiconductor layer disposed around an active layer has been recently proposed. However, in the case of a light emitting structure having a rod shape, there is a problem in that it is difficult to remove GaN.

The embodiment intends to propose a light emitting device capable of improving light efficiency by reducing light absorption by inserting a reflective layer into a light emitting structure having a rod structure including GaN.

2 is a plan view of the light emitting device according to the first embodiment, and FIG. 3 is a cross-sectional view of the light emitting device of FIG. 1.

2 to 3, the light emitting device 100 according to the first embodiment includes a substrate 101, a conductive semiconductor layer 110, a light emitting structure 150, an electrode layer 170, and first and second electrodes. (181, 183).

The substrate 101 may be a substrate made of a conductive or insulating material, or a substrate made of a light-transmitting or non-transmitting material. The substrate 101 may be selected from a group such as a sapphire substrate (Al ₂ O ₃ ), GaN, SiC, ZnO, Si, GaP, InP, Ga ₂ O _{3 and GaAs.} The substrate 101 may be used as a layer for supporting the light emitting device 100.

A compound semiconductor layer of a group II to group VI element may be disposed on the substrate 101. At least one of a nitride buffer layer (not shown) and an undoped semiconductor layer (not shown) may be disposed between the substrate 101 and the conductive semiconductor layer 110. The buffer layer and the undoped semiconductor layer may be formed of a compound semiconductor of a group III-V element, and the buffer layer reduces the difference in lattice constant from the substrate 101, and the undoped semiconductor layer is a GaN-based semiconductor that is not doped. Can be arranged as.

The conductive semiconductor layer 110 may be formed of a compound semiconductor of a group II to VI element, and is formed of at least one of GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaP, GaAs, GaAsP, and AlGaInP. Can be. The conductive semiconductor layer 110 is a layer for forming a first conductivity type semiconductor layer in a rod type, and may be formed of a compound semiconductor of a group III-V element, for example, GaN. The conductive semiconductor layer 110 may be formed as a single layer or a plurality of layers, but is not limited thereto. The conductive semiconductor layer 110 may include a first conductivity type dopant, and the first conductivity type dopant may be an n type dopant, for example, a dopant such as Si, Ge, Sn, Se, or Te. The conductive semiconductor layer 110 is a semiconductor layer 115 of a first conductivity type, and may be included in the light emitting structure 150, but is not limited thereto.

A mask layer 103 is disposed on the conductive semiconductor layer 110, and the mask layer 103 has a hole 105. A first conductivity type semiconductor layer 115 of a rod type is disposed in the hole 105. The mask layer 103 may be formed of an insulating material, for example SiO ₂ , SiO _x , SiO _x N _y , It may be formed of at least one of Si ₃ N ₄ and Al ₂ O _3. A plurality of holes 105 may be spaced apart from each other, for example, may be arranged at regular intervals, irregular intervals, or random intervals. The hole 105 may have a top view shape in a circular shape, an oval shape, or a polygonal shape.

The light emitting structure 150 includes a first conductivity type semiconductor layer 115, a reflective layer 140, an active layer 120, and a second conductivity type semiconductor layer 130. The light emitting structure 150 may further include a conductive semiconductor layer 110, but is not limited thereto.

4 is a perspective view of a light emitting structure 150 according to the first embodiment.

Referring to FIG. 4, the light emitting structure 150 according to the first embodiment may include a first conductivity type semiconductor layer 115, a reflective layer 140, an active layer 120, and a second conductivity type semiconductor layer 130. I can.

The first conductivity type semiconductor layer 115 _{includes a composition formula of In x} Al _y Ga _1-xy N (0≦x≦1, 0≦y≦1, 0≦x+y≦1). The first conductivity type semiconductor layer 115 is a compound semiconductor of a group III-V element doped with a first conductivity type dopant, such as GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaP, GaAs, It may contain at least one or more of GaAsP and AlGaInP. For example, the first conductivity type semiconductor layer 115 has a vertical rod shape and may include GaN. GaN may be selectively grown in a vertical direction (0001 direction), a facet direction, or a horizontal direction according to growth conditions, and may be formed in a vertical rod shape.

The first conductivity-type semiconductor layer 115 includes a first conductivity-type dopant, for example, an n-type dopant such as Si, Ge, Sn, Se, and Te. The first conductivity type semiconductor layer 115 may be formed as a single layer or multiple layers, but is not limited thereto.

The rod shape of the first conductivity-type semiconductor layer 115 may have a diameter in a range of 5 nm <diameter <2 μm. When the rod diameter is 2 μm or more, the area of the active layer 120 does not increase in proportion to the rod diameter, and the growth rate of the active layer 120 or the second conductivity type semiconductor layer 130 may be lowered, and quantum efficiency. There is also a slight problem with the improvement of. In addition, when the rod diameter is less than 5 nm, it is difficult to manufacture the hole 105 of the mask layer 103 or grow through the hole 105.

The rod shape of the first conductivity type semiconductor layer 115 may have a height in a range of 10 nm <height <5 μm, for example, 1 μm <height <3 μm. When the height of the rod is 5 μm or more, the injection distance of the carrier and the mobility of the carrier decrease, and there is a difficulty in growing the rod. When the height of the rod is less than 10 nm, there is a problem that the injection distance of the carrier, the mobility of the carrier, and the light emitting area are not improved as compared with the horizontal LED chip.

As shown in FIG. 4, the first conductivity type semiconductor layer 115 may have a polygonal column shape, for example, a hexagonal column shape. The first conductivity type semiconductor layer 115 may have the same lower width and the upper width, and the upper width may be narrower than the lower width or the upper width may be provided wider than the lower width according to processing conditions. In the case of the rod shape, the distance between the first conductivity-type semiconductor layers 115 is more spaced apart as it goes upward, so the interference between the adjacent first conductivity-type semiconductor layers 115 may be reduced. I can.

Since the first conductivity-type semiconductor layer 115 having a rod shape according to the embodiment has a plurality of side surfaces and top surfaces and faces the active layer 120, the area of the active layer 120 may be increased. In addition, since the first conductivity-type semiconductor layer 115 in a rod shape is disposed on the conductive semiconductor layer 110, the density of defects transmitted from the substrate 101 can be reduced. Accordingly, the crystal quality of the active layer 120 may be improved.

Meanwhile, the first conductivity type semiconductor layer 115 may be formed of the same material as the conductive semiconductor layer 110, and may be formed of, for example, GaN. The growth of the first conductivity type semiconductor layer 115 in the vertical direction should be promoted because it is difficult to form AlGaN or InGaN in the vertical direction.

However, as described above, since GaN absorbs light having a wavelength band of 400 nm or less, light efficiency may be rapidly deteriorated when the rod-shaped light emitting structure 150 emits light in the ultraviolet wavelength band. In the case of the light-emitting structure 150 of the rod shape as well as the light in the ultraviolet wavelength band, photons moving toward the second conductivity-type semiconductor layer 130 may be emitted to the outside. 115), the energy of the photon decreases, and the light extraction efficiency may decrease.

In the embodiment, in order to prevent such a problem, a reflective layer 140 may be disposed between the first conductivity type semiconductor layer 115 and the active layer 120. Specifically, the reflective layer 140 may be disposed to surround the first conductivity type semiconductor layer 115. More specifically, the reflective layer 140 may be disposed to surround the first conductivity type semiconductor layer 115. That is, the reflective layer 140 may be disposed on a plurality of side surfaces and upper surfaces of the first conductivity type semiconductor layer 115. Accordingly, the reflective layer 140 may include a plurality of side surfaces and an upper surface, and the plurality of side surfaces and an upper surface of the reflective layer 140 may face a plurality of side surfaces and upper surfaces of the first conductivity type semiconductor layer 115, respectively.

In addition, in the embodiment, the surface area of the reflective layer 140 may be larger than the surface area of the first conductivity type semiconductor layer 115. The reflective layer 140 may be disposed between the active layer 120 and the first conductivity type semiconductor layer 115. Specifically, the reflective layer 140 is formed between the outer surface of the first conductivity type semiconductor layer 115 and the inner surface of the active layer 120, and between the upper surface of the first conductivity type semiconductor layer 115 and the lower surface of the active layer 120. Can be placed on each.

The reflective layer 140 may include a Distributed Bragg Reflector (DBR), which is a plurality of semiconductor layers (eg, two layers) having different refractive indices. Since DBRs have different refractive indices, the active layer 120 may emit light to reflect light toward the first conductivity type semiconductor layer 115.

Specifically, in an embodiment, the reflective layer 140 includes _{a first semiconductor layer formed of Al a} In _b Ga _1-ab N (0≤a≤1, 0≤b≤1, 0≤a+b≤1) and Al _c A second semiconductor layer formed of IndGa _1-cd N (0≦c≦1, 0≦d≦1, 0≦c+dy≦1) may be included.

In an embodiment, the energy band gap difference between the first semiconductor layer and the second semiconductor layer may be between 0.5 eV and 1.5 eV. More specifically, the energy band gap difference between the first semiconductor layer and the second semiconductor layer may be 0.7 eV to 1 eV. When the energy band gap difference is less than 0.5 eV, the reflectance of the reflective layer 140 may be lowered, and when the energy band gap difference is more than 1.5 eV, the crystal quality deteriorates due to a sharp difference in composition between the first and second semiconductor layers. I can.

In an embodiment, the thickness of each of the first semiconductor layer and the second semiconductor layer constituting the reflective layer 140 may be between 20 nm and 80 nm. When the thickness of each semiconductor layer is less than 20 nm, the reflectance of the reflective layer 140 may decrease, and when the thickness of each semiconductor layer exceeds 80 nm, the quality of the semiconductor layer may decrease.

In addition, in the embodiment, the total thickness of the reflective layer 140 may be between 1 μm and 3 μm. When the thickness of the reflective layer 140 is less than 1 μm, the reflectance of the reflective layer 140 may decrease, and when the thickness of the reflective layer 140 exceeds 3 μm, the quality of the semiconductor layer may decrease.

In addition, in the embodiment, all of the semiconductor layers constituting the reflective layer 140 may include a first conductivity type dopant. The first conductivity type dopant may be an n-type dopant, and may be, for example, a dopant such as Si, Ge, Sn, Se, or Te. The reflective layer 140 may pass carriers generated in the first conductivity type semiconductor layer 115 to the active layer 120, and carriers generated in the reflective layer 140 itself may be injected into the active layer 120, The luminous efficiency can be improved.

The reflective layer 140 of this embodiment may improve light efficiency by reflecting light emitted from the active layer 120 toward the first conductivity type semiconductor layer 115. In particular, since the reflective layer 140 can rapidly reduce the light absorption rate of the first conductivity type semiconductor layer 115 in the light emitting device 100 emitting light in a wavelength band of 400 nm or less, its effect can be excellent.

In another embodiment, the DBR may be alternately deposited different dielectric layers, for example, each may be an oxide or nitride of an element selected from the group consisting of Si, Zr, Ta, Ti and Al, specifically, SiO ₂ layer And Si ₃ N ₄ layers. The reflective layer 140 may reflect light emitted from the side of the adjacent light emitting structure 150 by stacking different dielectric layers in a vertical direction. The vertical direction may be a direction parallel to the arrangement direction of the rods or may be a direction perpendicular to the upper surface of the substrate 101.

In another embodiment, the reflective layer 140 may employ an omni-directional reflector (ODR) layer other than the DBR layer. In the ODR layer, a metal reflective layer (not shown) may be disposed on the side of the light emitting structure 150, and a dielectric layer (not shown) may be disposed between the metal reflective layers. That is, the ODR layer may be formed in a stacked structure of a metal reflective layer/dielectric layer/metal reflective layer in a vertical direction. The metal reflective layer may be Ag or Al, and the dielectric layer may be a material such as _{SiO 2} or Si3N _4. The vertical direction may be a direction parallel to the arrangement direction of the rods or may be a direction perpendicular to the upper surface of the substrate 101.

Meanwhile, the active layer 120 may be disposed on the reflective layer 140. Specifically, the active layer 120 may be disposed to surround the reflective layer 140. The active layer 120 may be disposed on a plurality of side surfaces and upper surfaces of the reflective layer 140. The active layer 120 may include a plurality of side surfaces and an upper surface, and the plurality of side surfaces and an upper surface may respectively face the side surface and the upper surface of the reflective layer 140.

The active layer 120 selectively includes a single quantum well, a multiple quantum well (MQW), a quantum wire structure, or a quantum dot structure. The active layer 120 includes a cycle of a well layer and a barrier layer. The well layer includes _{a composition formula of In x} Al _y Ga _1-xy N (0≤x≤1, 0≤y≤1, 0≤x+y≤1), and the barrier layer is In _x Al _y Ga _1-xy A composition formula of N (0≦x≦1, 0≦y≦1, 0≦x+y≦1) may be included. The cycle of the well layer/barrier layer is, for example, InGaN/GaN, InGaN/AlGaN, InGaN/InGaN, GaN/AlGaN, InAlGaN/InAlGaN, AlGaAs/GaAs, InGaAs/GaAs, InGaP/GaP, AlInGaP/InGaP, InP/GaAs. It can be implemented in pairs. The cycle of the well layer/barrier layer may be 2 or more cycles, and the barrier layer may be formed of a semiconductor material having a band gap wider than that of the well layer. The active layer 120 may selectively emit light within a wavelength range from visible light to ultraviolet light, for example, light having a peak wavelength of visible light or light having a blue peak wavelength, but is not limited thereto. In the embodiment, the active layer 120 is described as emitting light in the ultraviolet wavelength range, but is not limited thereto.

An electron blocking layer (not shown) may be formed between the active layer 120 and the second conductivity type semiconductor layer 130. The electron blocking layer may be formed of a GaN-based semiconductor, and may be formed of a material having a band gap equal to or greater than the band gap of the active layer 120.

The second conductive semiconductor layer is disposed to surround the active layer 120. The second conductivity type semiconductor layer 130 may include a plurality of side surfaces and top surfaces, and the plurality of side surfaces and top surfaces may face the side surfaces and top surfaces of the active layer 120.

The second conductivity type semiconductor layer 130 is a semiconductor doped with a second conductivity type dopant, for example, In _x Al _y Ga _1-xy N (0≤x≤1, 0≤y≤1, 0≤x+y≤1) Include the composition formula of ). The second conductivity type semiconductor layer 130 may be formed of at least one of compound semiconductors such as GaN, InN, AlN, InGaN, AlGaN, InAlGaN, AlInN, AlGaAs, GaP, GaAs, GaAsP, and AlGaInP. When the active layer 120 emits light in the ultraviolet wavelength band, the second conductivity type semiconductor layer 130 may be configured to include AlGaN. In addition, the second conductivity-type semiconductor layer 130 may be a p-type semiconductor layer, and the second conductivity-type dopant is a p-type dopant, and may include Mg, Zn, Ca, Sr, and Ba.

In the rod-shaped light-emitting structure 150 of the embodiment, the reflective layer 140 and the second conductivity-type semiconductor layer 130 have a plurality of side surfaces and upper surfaces to face the active layer 120, thereby increasing the area of the active layer 120 As a result, the luminous efficiency can be improved. In addition, since the first conductivity-type semiconductor layer 115 in a rod shape is disposed on the conductive semiconductor layer 110, the density of defects transmitted from the substrate 101 can be reduced. Accordingly, the crystal quality of the active layer 120 may be improved.

In addition, the reflective layer 140 according to the embodiment may reflect light emitted from the active layer 120 toward the first conductivity type semiconductor layer 115 to improve light efficiency. In particular, since the reflective layer 140 can prevent light absorption of the first conductive type semiconductor layer 115 in the light emitting device 100 that emits light in the ultraviolet wavelength band, its effect can be excellent.

5 is a perspective view of a light emitting structure 150 according to a second embodiment, FIG. 6 is a cross-sectional view of a light emitting structure 150 according to a third embodiment, and FIG. 7 is a light emitting structure 150 according to the fourth embodiment It is a cross-sectional view of.

In the second to fourth embodiments, the shape of the light emitting structure 150 of the first embodiment is modified, and similar configurations are denoted by the same reference numerals, and redundant descriptions will be omitted.

Referring to FIG. 5, the first conductive semiconductor layer 115A of the light emitting structure 151 according to the second embodiment may have a rod shape of a hexagonal column or more, for example, a dodecagonal column shape. Due to the external shape of the first conductivity-type semiconductor layer 115A, the reflective layer 141, the active layer 121, and the second conductivity-type semiconductor layer 131 surrounding them may have a dodecagonal column shape. Accordingly, the area of the active layer 121 may be increased, and light extraction efficiency may be improved. As another example, the first conductivity-type semiconductor layer 115A may be formed in a polygonal pillar shape excluding a hexagonal or twelve pillar, for example, a triangular pillar or a polygonal pillar shape greater than or equal to, but is not limited thereto.

Referring to FIG. 6, the light emitting structure 152 according to the third embodiment may have a horizontal rod shape. At this time, the horizontal rod shape refers to a structure in which the first conductivity-type semiconductor layer 115B, the reflective layer 142, the active layer 122, and the second conductivity-type semiconductor layer 132 are sequentially stacked in a vertical direction.

Specifically, the light emitting structure 152 according to the third embodiment may have a triangular pillar shape, and one side of the triangular pillar may be a structure disposed on the conductive semiconductor layer 110. Accordingly, a side cross-section of the triangular pillar-shaped light emitting structure 152 may have a triangular shape.

More specifically, in the side cross-sectional view, the first conductivity-type semiconductor layer 115B may have a shape protruding from the conductive semiconductor layer 110 in a triangular shape. In addition, the reflective layer 142 may be disposed to cover an upper surface of the first conductivity type semiconductor layer 115B and an upper surface of the conductive semiconductor layer 110 on which the first conductivity type semiconductor layer 115B is not formed. In another aspect, the reflective layer 142 may be disposed between the first conductive semiconductor layer 115B and the conductive semiconductor layer 110 and the active layer 122.

The reflective layer 142 may reflect light emitted from the active layer 122 to the first conductive semiconductor layer 115B and the conductive semiconductor layer 110 to improve light efficiency.

In addition, the active layer 122 may be disposed on the reflective layer 142, and the second conductivity type semiconductor layer 132 may be disposed on the active layer 122.

Referring to FIG. 7, the light emitting structure 153 according to the fourth embodiment may have a horizontal rod shape. At this time, the horizontal rod shape means a structure in which the first conductive semiconductor layer 115C, the reflective layer 143, the active layer 123, and the second conductive semiconductor layer 133 are sequentially stacked in the vertical direction.

Specifically, the light emitting structure 153 according to the fourth embodiment may have a rectangular pillar shape, and one side of the rectangular pillar may be a structure disposed on the conductive semiconductor layer 110. Accordingly, a side cross-section of the light emitting structure 153 having a square pillar shape may have a square shape.

More specifically, in the side cross-sectional view, the first conductivity-type semiconductor layer 115C may have a shape protruding from the conductive semiconductor layer 110 in a square shape. In addition, the reflective layer 143 may be disposed to cover an upper surface of the first conductivity type semiconductor layer 115C and an upper surface of the conductive semiconductor layer 110 on which the first conductivity type semiconductor layer 115C is not formed. In another aspect, the reflective layer 143 may be disposed between the first conductive semiconductor layer 115C and the conductive semiconductor layer 110 and the active layer 123.

The reflective layer 143 may improve light efficiency by reflecting light emitted from the active layer 123 to the first conductive semiconductor layer 115C and the conductive semiconductor layer 110.

In addition, the active layer 123 may be disposed on the reflective layer 143, and the second conductivity type semiconductor layer 133 may be disposed on the active layer 123.

Meanwhile, an insulating layer 160 may be disposed in a region between the plurality of light emitting structures 150. The insulating layer 160 may be disposed between the plurality of light emitting structures 150 and may contact the mask layer 103. The insulating layer 160 may be in contact with the circumference of the second conductivity type semiconductor layer 130. In an embodiment, the insulating layer 160 is SiO ₂ , SiO _x , SiO _x N _y , It may include at least one of Si ₃ N ₄ and Al ₂ O _3.

In addition, as shown in FIG. 2, the electrode layer 170 may be disposed on the rod-shaped light emitting structure 150. The electrode layer 170 may cover the plurality of rod-shaped light emitting structures 150. The electrode layer 170 may be disposed on the upper surface of the second conductivity type semiconductor layer 130. The electrode layer 170 may include a protrusion, and the protrusion may be disposed on the insulating layer 160 through a region between the plurality of light emitting structures 150. The electrode layer 170 may contact an upper surface of the second conductivity type semiconductor layer 130, and the protrusion may contact a side surface of the second conductivity type semiconductor layer 130. Accordingly, the electrode layer 170 may supply power to the second conductivity type semiconductor layer 130.

In an embodiment, the electrode layer 170 may be selected from a light-transmitting material or a metal material, for example, indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), or indium aluminum zinc oxide (IAZO). , IGZO(indium gallium zinc oxide), IGTO(indium gallium tin oxide), AZO(aluminum zinc oxide), ATO(antimony tin oxide), GZO(gallium zinc oxide), IrOx, RuOx, RuOx/ITO, Ni/IrOx/ It may include at least one of Au, and Ni/IrOx/Au/ITO, but is not limited to these materials. The electrode layer 170 may be formed of a metal that reflects light, not a material that transmits light, but is not limited thereto.

In an embodiment, the first electrode 181 may be electrically connected to or in contact with at least one of the conductive semiconductor layer 110 and the first conductive semiconductor layer 115. The first electrode 181 may be disposed on the contact part 112 of the conductive semiconductor layer 110, for example. The contact portion 112 of the conductive semiconductor layer 110 may protrude from other regions, but the embodiment is not limited thereto. As another example, the contact part 112 may not protrude. The first electrode 181 includes an electrode pad, and may be formed in a predetermined pattern, but is not limited thereto. The first electrode 181 may be branched into an arm structure for current diffusion. The first electrode 181 includes a single metal or an alloy among metals such as Ti, Al, In, Ta, Pd, Co, Ni, Si, Ge, Ag, and Au, and may be formed as a single layer or multiple layers.

In an embodiment, the second electrode 183 may be electrically connected to or in contact with at least one of the electrode layer 170 and the second conductivity type semiconductor layer 130. The second electrode 183 may be disposed on the electrode layer 170. The second electrode 183 includes an electrode pad and may be formed in a predetermined pattern, but is not limited thereto. The second electrode 183 may be branched into an arm structure to supply current. The second electrode 183 includes a single metal or an alloy among metals such as Ti, Al, In, Ta, Pd, Co, Ni, Si, Ge, Ag, and Au, and may be formed as a single layer or multiple layers.

The embodiment is a light emitting area and luminous efficiency by the light emitting structure 150 including the first conductivity type semiconductor layer 115 / reflective layer 140 / active layer 120 / second conductivity type semiconductor layer 130 in a rod shape. This can be improved. In addition, the rod-shaped light-emitting structure 150 according to the embodiment may improve light efficiency by preventing light absorption of the first conductive type semiconductor layer 115 with the reflective layer 140. In addition, since the density of defects propagating from the substrate 101 can be blocked, the crystal quality of the active layer 120 can be prevented from deteriorating, and internal quantum efficiency can be improved. In addition, when light is emitted through the side and upper surfaces of the light-emitting structure 150, light extraction efficiency may be improved due to the angular shape of the light-emitting structure 150.

As another embodiment, in the light emitting structure 150, the first conductivity-type semiconductor layer 115 may be a p-type semiconductor layer, and the second conductivity-type semiconductor layer 130 may be formed as an n-type semiconductor layer. I don't.

8 is a side cross-sectional view showing the light emitting device 101 according to the second embodiment.

In the description of the second embodiment, the same configuration as that of the embodiment disclosed above will be referred to the description of the embodiment disclosed above.

Referring to FIG. 8, the light emitting device 101 according to the second embodiment includes a substrate 101, a conductive semiconductor layer 110, a light emitting structure 150, an electrode layer 170, an insulating layer 160, and the first and It includes second electrodes 181 and 183.

The mask layer (103 in FIG. 2) disposed between the conductive semiconductor layer 110 and the light emitting structure 150 may be removed. Accordingly, the reflective layer 140, the active layer 120, and the second conductivity type semiconductor layer 130 of the adjacent light emitting structure 150 may be connected to each other. The inner extension 140A of the reflective layer 140 of each light emitting structure 150 extends between the insulating layer 160 and the conductive semiconductor layer 110 to connect adjacent reflective layers 140. In addition, the outer extension part 140B of the reflective layer 140 may contact the inner side of the insulating layer 160. The inner and outer extension portions 140A and 140B of the reflective layer 140 may extend in a horizontal direction.

The extended portion 120A of the active layer 120 is disposed on the extended portion 140A of the reflective layer 140. The extended portion 120A of the active layer 120 extends in a horizontal direction and may be connected to the active layer 120 of another light emitting structure 150 or may be disposed on the outer extended portion 140A of the reflective layer 140.

In addition, an extension portion 130A of the second conductivity type semiconductor layer 130 is disposed on the extension portion 120A of the active layer 120. The extension 130A of the second conductivity type semiconductor layer 130 extends in a horizontal direction and is connected to the second conductivity type semiconductor layer 130 of another light emitting structure 150 or an outer extension of the reflective layer 140 It can be placed on (140B).

The extensions 140A and 140B of the reflective layer 140, the extensions 120A and 120B of the active layer 120, and the extension 130A of the second conductivity type semiconductor layer 130 are a first conductivity type semiconductor having a rod shape. After the layer 115 is formed, it may be formed to extend on the region from which the mask layer 103 is removed.

An insulating layer 160 may be disposed between the extended portion 130A of the second conductivity type semiconductor layer 130 and the electrode layer 170. Part of the insulating layer 160 is disposed on the side of the light-emitting structure 150 disposed at the outermost of the light-emitting structures 150, the outer extension 140B of the reflective layer 140 and the outer extension of the active layer 120 (120B) and the conductive semiconductor layer 110 may be in contact. Since the extended portions of the active layer 120 and the second conductivity type semiconductor layer 130 are additionally disposed, the total surface area of the active layer 120 and the second conductivity type semiconductor layer 130 is increased, and the light emitting area is further increased. I can.

9 is a side cross-sectional view showing the light emitting device 102 according to the third embodiment. In the description of the third embodiment, the same configuration as that of the embodiment disclosed above will be referred to the description of the embodiment disclosed above.

9, the light emitting device 102 includes a conductive semiconductor layer 110, a rod-shaped light emitting structure 150, an electrode layer 170, an insulating layer 160, a first electrode 181A, and a second electrode ( 183).

The first electrode 181A is disposed under the conductive semiconductor layer 110 and includes a plurality of conductive layers. The first electrode 181A includes a contact layer 185, a second reflective layer 186, a bonding layer 187, and a conductive support member 188.

The contact layer 185 is disposed under the conductive semiconductor layer 110. The contact layer 185 is electrically connected to a conductive material, for example, a conductive semiconductor layer 110. For example, the contact layer 185 may come into ohmic contact with the conductive semiconductor layer 110. The contact layer 185 may be selected from a light-transmitting conductive material or a metal material, for example, indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), and IGZO. (indium gallium zinc oxide), IGTO (indium gallium tin oxide), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IrOx, RuOx, RuOx/ITO, Ni/IrOx/Au, And at least one of Ni/IrOx/Au/ITO, but is not limited to such a material.

The second reflective layer 186 is disposed under the contact layer 185 to reflect incident light. The second reflective layer 186 may be formed from a material composed of a metal such as Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, Hf, and optional combinations thereof, and may be formed of a single layer or It can be formed in multiple layers.

The bonding layer 187 is disposed under the second reflective layer 186, and the bonding layer 187 includes at least one of a metal material such as Au, Sn, Nb, Pb, In, and Mo, and is a single layer or a different material. It can be formed in multiple layers. The bonding layer 187 bonds the second reflective layer 186 and the conductive support member 188 to each other.

The conductive support member 188 may be formed under the bonding layer 187. The conductive support member 188 is formed of, for example, at least one metal or two or more alloys of Ti, Cr, Ni, Al, Pt, Au, W, Cu, Mo, and Cu-W, or impurities are implanted. It may be formed of a semiconductor substrate (eg, Si, Ge, GaN, GaAs, ZnO, SiC, SiGe, etc.). The conductive support member 188 may be a multi-layered metal layer or a layer containing carbon.

The second electrode 183 may be disposed on the electrode layer 170. The first electrode 181A and the second electrode 183 may be disposed in opposite directions to each other. In the light emitting device 102, most of the light may be reflected in the vertical direction by the second reflective layer 186.

10 to 16 are views showing a manufacturing process of the light emitting device 100 of FIG. 2.

10 and 11, a conductive semiconductor layer 110 may be formed on a substrate 101 by a growth device. The substrate 101 may be an insulating or conductive substrate. The substrate 101 may be formed of, for example, _{at least one of a sapphire substrate (Al 2} O ₃ ), SiC, GaAs, GaN, ZnO, Si, GaP, InP, and Ge, but is not limited thereto.

The semiconductor layer grown on the substrate 101 is, for example, metal organic chemical vapor deposition (MOCVD), chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD). ), Molecular Beam Epitaxial (MBE), Hydride Vapor Phase Epitaxial (HVPE), or the like, but is not limited thereto.

The conductive semiconductor layer 110 may be formed of a compound semiconductor of a group II to VI element on the substrate 101, for example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaP, GaAs, GaAsP , AlGaInP may be formed of at least one of. At least one of a buffer layer and an undoped semiconductor layer (not shown) may be formed between the conductive semiconductor layer 110 and the substrate 101.

A mask layer 103 may be formed on the conductive semiconductor layer 110, and a plurality of holes 105 may be formed in the mask layer 103. The mask layer 103 is SiO ₂ , SiO _x , SiO _x N _y , It _{is deposited with at least one material of Si 3} N ₄ and Al ₂ O ₃ , and the hole 105 may be formed in a predetermined area by a photolithography process.

A first conductivity type semiconductor layer 115 is grown on the hole 105. The first conductivity type semiconductor layer 115 may be grown in a vertical growth mode in a rod shape. The conductive semiconductor layer 110 and the first conductive semiconductor layer 115 may include an n-type dopant. The first conductivity type semiconductor layer 115 may be formed of a GaN material for vertical growth, but is not limited thereto.

The first conductivity-type semiconductor layer 115 having a rod shape is disposed on the hole 105, and a plurality of the first conductive semiconductor layers 115 are spaced apart from each other. The rod shape may be a polygonal column shape, for example, a hexagonal column or a 12-angled column, or another column shape. Here, a mask layer 104 may be further disposed on a partial region of the conductive semiconductor layer 110, for example, the contact part 112, so that the thickness of the contact part 112 of the conductive semiconductor layer 110 may be adjusted. The contact part 112 of the conductive semiconductor layer 110 may not be formed, but is not limited thereto.

Referring to FIG. 12, a reflective layer 140 is formed on the surface of the first conductivity type semiconductor layer 115 in a rod shape, and the reflective layer 140 surrounds the first conductivity type semiconductor layer 115. The reflective layer 140 is disposed on the side and upper surfaces of the first conductivity type semiconductor layer 115. The reflective layer 140 may contact the upper surface of the mask layer 103.

Next, as shown in FIG. 13, an active layer 120 is formed on the surface of the reflective layer 140.

The active layer 120 includes a cycle of a well layer and a barrier layer. The well layer includes _{a composition formula of In x} Al _y Ga _1-xy N (0≤x≤1, 0≤y≤1, 0≤x+y≤1), and the barrier layer is In _x Al _y Ga _1-xy A composition formula of N (0≦x≦1, 0≦y≦1, 0≦x+y≦1) may be included. The cycle of the well layer/barrier layer is, for example, InGaN/GaN, InGaN/AlGaN, InGaN/InGaN, GaN/AlGaN, InAlGaN/InAlGaN, AlGaAs/GaAs, InGaAs/GaAs, InGaP/GaP, AlInGaP/InGaP, InP/GaAs. It can be implemented in pairs. The cycle of the well layer/barrier layer may be two or more cycles, and the barrier layer may be formed of a semiconductor material having a band gap wider than that of the well layer. The active layer 120 may selectively emit light within a wavelength range from visible light to ultraviolet light, for example, a peak wavelength having visible light or a blue peak wavelength, but is not limited thereto.

Thereafter, as shown in FIG. 14, a second conductivity type semiconductor layer 130 is formed on the surface of the active layer 120. The second conductivity type semiconductor layer 130 may be formed of a compound semiconductor of a group II to VI element, for example, among GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaP, GaAs, GaAsP, and AlGaInP. It may be formed of at least one.

14 and 15, the upper surface of the mask layer 103 is exposed in the region A1 between the rod-shaped light emitting structures 150. The insulating layer 160 is deposited in the region A1, and the electrode layer 170 is deposited on the insulating layer 160 and the second conductivity type semiconductor layer 130. Here, the protrusion of the electrode layer 170 extends to the region A1 and may contact side surfaces of the insulating layer 160 and the second conductivity type semiconductor layer 130. The electrode layer 170 may be formed of a transparent material or a reflective material, but is not limited thereto. The mask layer 104 disposed on the contact portion 112 of the conductive semiconductor layer 110 is removed.

15 and 16, a first electrode 181 is disposed on the contact portion 112 of the conductive semiconductor layer 110, and a second electrode 183 is disposed on the electrode layer 170. Accordingly, the light emitting device 100 as shown in FIG. 2 may be provided.

17 is a diagram illustrating a package of a light emitting device 100 having the light emitting device 100 of FIG. 2.

Referring to FIG. 17, the light emitting device 100 package 200 includes a body 210, a first lead electrode 211 and a second lead electrode 212 disposed at least in part on the body 210, and a body The light emitting device 100 electrically connected to the first lead electrode 211 and the second lead electrode 212 on 210, and a molding member 220 surrounding the light emitting device 100 on the body 210 ).

The body 210 may be formed of a silicon material, a synthetic resin material, or a metal material. The body 210 includes a reflective portion 215 having a cavity inside and an inclined surface around the cavity when viewed from above.

The first lead electrode 211 and the second lead electrode 212 are electrically separated from each other, and may be formed to penetrate the body 210. That is, a part of the first lead electrode 211 and the second lead electrode 212 may be disposed inside the cavity, and the other part may be disposed outside the body 210.

The first lead electrode 211 and the second lead electrode 212 supply power to the light emitting device 100 and reflect light generated from the light emitting device 100 to increase light efficiency. It can also function to discharge the heat generated by 100) to the outside.

The light emitting device 100 may be installed on the body 210 or on the first lead electrode 211 or/and the second lead electrode 212. The wire 216 connected to the light emitting device 100 may be electrically connected to the first lead electrode 211 and the second lead electrode 212, but is not limited thereto.

The molding member 220 may surround the light emitting device 100 to protect the light emitting device 100. Further, the molding member 220 includes a phosphor, and the wavelength of light emitted from the light emitting device 100 may be changed by the phosphor.

The light emitting device 100 or the light emitting device 100 package according to the embodiment may be applied to a light unit. The light unit includes a structure in which a plurality of light emitting devices 100 or packages of the light emitting devices 100 are arrayed, and may include a lighting lamp, a traffic light, a vehicle headlight, an electric sign, and the like.

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.

Claims (16)

A conductive semiconductor layer;
A first conductive type semiconductor layer disposed to be spaced apart from each other on the conductive semiconductor layer and having a plurality of rod shapes;
A reflective layer disposed to surround a plurality of side surfaces and upper surfaces of the first conductivity type semiconductor layer;
An active layer disposed to surround the reflective layer;
A second conductivity type semiconductor layer disposed to surround the active layer;
An electrode layer disposed on the second conductivity type semiconductor layer; And
Including an insulating layer disposed between the second conductivity type semiconductor layer,
The first conductivity-type semiconductor layer includes an n-type dopant,
The second conductivity-type semiconductor layer includes a p-type dopant,
The reflective layer includes a plurality of side surfaces and an upper surface respectively facing a plurality of side surfaces and an upper surface of the first conductivity type semiconductor layer,
The surface area of the reflective layer is larger than the surface area of the first conductivity-type semiconductor layer,
The thickness of the reflective layer is 1 μm to 3 μm,
The reflective layer includes a Distributed Bragg Reflector (DBR) including a plurality of semiconductor layers having different refractive indices,
The distributed Bragg reflective layer,
A first semiconductor layer; And
And a second semiconductor layer having an energy band gap difference of 0.5 eV to 1.5 eV from the first semiconductor layer,
The first and second semiconductor layers include the n-type dopant,
Each of the first and second semiconductor layers have a thickness of 20 nm to 80 nm,
The active layer includes a plurality of side surfaces and an upper surface respectively facing a plurality of side surfaces and an upper surface of the reflective layer,
The active layer, the second conductive semiconductor layer, and the reflective layer include an extension part extending between the insulating layer and the conductive semiconductor layer,
An extended portion of the active layer is disposed on the extended portion of the reflective layer, and an extended portion of the second conductive type semiconductor layer is disposed on the extended portion of the active layer,
The insulating layer is disposed between the extended portion of the second conductivity type semiconductor layer and the electrode layer,
The uppermost surface of the insulating layer is a light emitting device disposed below the uppermost surface of the first conductive semiconductor layer and the upper surface of the reflective layer. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete

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