KR20180087677A - Semiconductor Device And Light Apparatus - Google Patents

Abstract

An embodiment of the present invention relates to a semiconductor element and a lighting apparatus. According to an embodiment of the present invention, a light emitting element includes an electron blocking layer between an activation layer and a second conductive semiconductor layer. Accordingly, since the electron blocking layer with improved electrical characteristics can be provided, a doping level of the electron blocking layer can be improved and the efficiency of the light emitting element can be improved.

Description

TECHNICAL FIELD [0001] The present invention relates to a semiconductor device and a lighting apparatus,

Embodiments relate to semiconductor devices, and more particularly, to semiconductor devices and lighting devices.

Semiconductor devices including compounds such as GaN and AlGaN have many merits such as wide and easy bandgap energy, and can be used variously as light emitting devices, light receiving devices, and various diodes.

Particularly, a light emitting device such as a light emitting diode or a laser diode using a semiconductor material of Group 3-5 or 2-6 group semiconductors can be applied to various devices such as a red, Blue, and ultraviolet rays. By using fluorescent materials or combining colors, it is possible to realize a white light beam with high efficiency. Also, compared to conventional light sources such as fluorescent lamps and incandescent lamps, low power consumption, , Safety, and environmental friendliness.

In addition, when a light-receiving element such as a photodetector or a solar cell is manufactured using a semiconductor material of Group 3-5 or Group 2-6 compound semiconductor, development of a device material absorbs light of various wavelength regions to generate a photocurrent , It is possible to use light in various wavelength ranges from the gamma ray to the radio wave region. It also has advantages of fast response speed, safety, environmental friendliness and easy control of device materials, so it can be easily used for power control or microwave circuit or communication module.

Accordingly, the semiconductor device can be replaced with a transmission module of an optical communication means, a light emitting diode backlight replacing a cold cathode fluorescent lamp (CCFL) constituting a backlight of an LCD (Liquid Crystal Display) display device, White light emitting diodes (LEDs), automotive headlights, traffic lights, and gas and fire sensors. In addition, semiconductor devices can be applied to high frequency application circuits, other power control devices, and communication modules.

The light emitting device has a structure in which an active layer is disposed between an n-type semiconductor layer doped with an n-type impurity and a p-type semiconductor layer doped with a p-type impurity. In such a semiconductor light emitting device, electrons are supplied from the n-type semiconductor layer, holes are supplied from the p-type semiconductor layer, and light is generated while electrons and holes are recombined in the active layer.

In the prior art, electrons have a higher mobility than holes, so that they are not coupled with holes in the active layer and are prevented from diffusing into the p-type semiconductor layer. In order to prevent diffusion of electrons and holes into the p- Thereby improving the luminous efficiency of the light emitting device. However, when Mg is doped in the electron blocking layer, the crystallinity of the electron blocking layer due to doping deteriorates and the characteristics of the electron blocking layer due to segregation of Mg are deteriorated.

Further, in the prior art, a hole injection layer is formed between the p-type semiconductor layer and the active layer to improve injection efficiency of holes injected from the p-type semiconductor layer into the active layer.

However, resistance is generated at the interface between the plurality of formed hole injection layers to lower the hole injection efficiency, and the characteristics change depending on the Al concentration of the hole injection layer, which lowers the hole injection efficiency of the hole injection layer.

The embodiment is intended to provide an electron blocking layer capable of improving the Mg doping level of the electron blocking layer.

The embodiment is intended to provide an electron blocking layer having improved electrical characteristics and crystallinity.

In the embodiment, it is intended to provide a hole injection layer having improved hole injection efficiency by reducing the resistance generated at the interface of the hole injection layer.

A light emitting device according to an embodiment includes a substrate and a light emitting structure disposed on the substrate, wherein the light emitting structure includes a first conductive semiconductor layer and a second conductive semiconductor layer, the first conductive semiconductor layer, An active layer disposed between the conductive semiconductor layers, and an electron blocking layer comprising an InAlGaN-based layer and an AlGaN-based layer and a GaN-based layer alternately arranged between the active layer and the second conductive type semiconductor layer, Layer may include a region where the band gap energy decreases as the active layer approaches the active layer and a region where the band gap energy increases as the second conductive semiconductor layer approaches the active layer.

The magnesium concentration of the electron blocking layer of the light emitting device according to the embodiment may decrease as the distance from the interface between the InAlGaN series layer and the GaN series layer increases.

In the InAlGaN-based layer of the light-emitting device according to the embodiment, the closer to the active layer, the lower the concentration of magnesium.

The magnesium concentration of the electron blocking layer of the light emitting device according to the embodiment may be highest at the interface between the InAlGaN-based layer and the GaN-based layer.

The band gap energy of the InAlGaN-based layer of the light emitting device according to the embodiment may be higher than the band gap energy of the AlGaN-based layer and the GaN-based layer.

The light emitting device according to the embodiment may further include a hole injection layer disposed between the second conductivity type semiconductor layer and the active layer and including a p-AlGaN series layer and a GaN series layer.

The p-AlGaN-based layer of the light emitting device according to the embodiment may include a region where the Al concentration decreases as the active layer approaches the p-AlGaN-based layer.

The p-AlGaN-based layer of the light emitting device according to the embodiment may include a region where the Al concentration increases as the layer approaches the second conductivity type semiconductor layer.

The p-AlGaN-based layer of the light emitting device according to the embodiment may include a region where bandgap energy increases as the active layer approaches the active layer.

Embodiments can provide a semiconductor device and a lighting device including an electron blocking layer having improved electrical characteristics.

The embodiment can provide a semiconductor device and a lighting device including an electron blocking layer with an improved Mg doping level.

The embodiment can provide a semiconductor element and a lighting device including a hole injection layer having improved electrical characteristics.

1 is a cross-sectional view of a light emitting device according to an embodiment.
2A is a diagram showing an energy band diagram of a light emitting device electron blocking layer according to an embodiment.
2B is a diagram showing a continuous energy band diagram of the light emitting device barrier layer according to the embodiment.
3 is a table showing the light output of the electron blocking layer of the light emitting device according to the embodiment.
4 is a view showing an envelope band diagram of a hole injection layer of a light emitting device according to an embodiment.
5 is a table showing the light output of the hole injection layer of the light emitting device according to the embodiment.
6 to 8 are sectional views showing a manufacturing process of the light emitting device according to the embodiment.
9 is a cross-sectional view of a light emitting device package according to an embodiment.
10 is a perspective view of a lighting apparatus according to the embodiment.

The embodiments may be modified in other forms or various embodiments may be combined with each other, and the scope of the present invention is not limited to each embodiment described below.

Although not described in the context of another embodiment, unless otherwise described or contradicted by the description in another embodiment, the description in relation to another embodiment may be understood.

For example, if the features of configuration A are described in a particular embodiment, and the features of configuration B are described in another embodiment, even if the embodiment in which configuration A and configuration B are combined is not explicitly described, It is to be understood that they fall within the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a first embodiment of the present invention; FIG.

In the description of the embodiment according to the present invention, in the case of being described as being formed "on or under" of each element, the upper (upper) or lower (lower) or under are all such that two elements are in direct contact with each other or one or more other elements are indirectly formed between the two elements. Also, when expressed as "on or under", it may include not only an upward direction but also a downward direction with respect to one element.

The semiconductor device may include various electronic devices such as a light emitting device and a light receiving device. The light emitting device and the light receiving device may include a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer.

The semiconductor device according to this embodiment may be a light emitting device.

The light emitting device emits light by recombination of electrons and holes, and the wavelength of the light is determined by the energy band gap inherent to the material. Thus, the light emitted may vary depending on the composition of the material.

1, 2A and 2B, a light emitting device 100 according to an embodiment includes a substrate 10, an unshown semiconductor layer 20, a first conductivity type semiconductor layer 30, And the electron blocking layer 60 including the InGaN-based semiconductor layer 70 and the active layer 40, the hole injection layer 50, the AlGaN-based layer 61, the InAlGaN-based layer 62 and the GaN- One can be included.

The substrate 10 may be formed of a material having excellent thermal conductivity. The substrate 10 may be a conductive substrate or an insulating substrate. For example, the substrate 10 is a sapphire (Al ₂ O _3), SiC, Si, GaAs, GaN, ZnO, GaP, InP, Ge, and Ga ₂ 0 ₃ May be used. A concave-convex structure may be formed on the substrate 10, but the present invention is not limited thereto.

On the substrate 10, an undoped semiconductor layer 20 may be disposed. The undoped semiconductor layer 20 may be formed of an undoped GaN layer doped with a first conductive dopant and a second conductive dopant. The undoped semiconductor layer 20 may have lower electrical conductivity than the first conductive semiconductor layer 30 or the second conductive semiconductor layer 70 because the conductive dopant is not doped.

The first conductivity type semiconductor layer 30 may be disposed on the undoped semiconductor layer 20. The first conductivity type semiconductor layer 30 may be formed of at least one of a semiconductor compound, for example, a Group III-V compound semiconductor or a Group II-VI compound semiconductor. The first conductive semiconductor layer 30 may be a single layer or a multilayer. The first conductive semiconductor layer 30 may be doped with a first conductive dopant. For example, when the first conductive semiconductor layer 30 is an n-type semiconductor layer, it may include an n-type dopant. The n-type dopant may include, but not limited to, Si, Ge, Sn, Se, and Te.

Wherein the first conductive type semiconductor layer 30 is _{In x Al y Ga 1 -x- y} P (0≤≤x≤≤1, 0≤≤y≤≤1, 0≤≤x + y≤≤1) But is not limited to, a semiconductor material having a composition formula. For example, the first conductive semiconductor layer 30 may be formed of any one or more of AlGaP, InGaP, AlInGaP, InP, GaN, InN, AlN, InGaN, AlGaN, InAlGaN, AlInN, AlGaAs, InGaAs, AlInGaAs, .

The active layer 40 may be disposed on the first conductive semiconductor layer 30. The active layer 40 may be disposed on the substrate 10. The active layer 40 may be disposed between the first conductive semiconductor layer 30 and the second conductive semiconductor layer 70.

The active layer 40 can meet with electrons (or holes) injected through the first conductive type semiconductor layer 30 and holes (or electrons) injected through the second conductive type semiconductor layer 70 with each other. The active layer 40 may emit light due to a band gap difference of an energy band according to the material of the active layer 40 by the electrons and the holes. The active layer 40 may emit at least one wavelength of ultraviolet light, blue light, green light, and red light.

The active layer 40 may optionally include a single quantum well, a multiple quantum well (MQW), a quantum wire structure, or a quantum dot structure. The active layer 40 may be composed of a compound semiconductor. The active layer 40 may be formed of at least one of Group III-V-VI or Group V-VI compound semiconductors.

The active layer 40 may include a quantum well layer and a quantum barrier layer. When the active layer 40 is implemented as a multiple quantum well structure, the quantum well layer and the quantum barrier layer may be alternately arranged. The quantum well layer and a quantum barrier layer has a composition formula of _{In x Al y Ga 1 -x- y} P (0≤≤x≤≤1, 0≤≤y≤1, 0≤≤x + y≤≤1) respectively GaN / AlGaAs, InGaAs / AlGaAs, InGaN / InGaN, InGaN / InGaN, GaN / AlGaN, InAlGaN / GaN, GaAs / AlGaAs, InGaP / AlGaP, But the present invention is not limited thereto. The quantum well layer may be formed of a material having a bandgap lower than that of the quantum barrier layer.

A hole injection layer 50 may be disposed on the active layer 40. The hole injection layer 50 will be described later.

Electrons supplied from the first conductive semiconductor layer 30 to the active layer 40 have a high mobility and are not recombined with holes and pass through the active layer 40 to the second conductive semiconductor layer 70 You can escape. At this time, the escaping electrons may cause a leakage current. The electron blocking layer 60 is disposed between the active layer 40 and the second conductivity type semiconductor layer 70 so that electrons can pass through the active layer 40 to form the second conductivity type semiconductor layer 70, Can not be prevented from escaping to.

Accordingly, the electron blocking layer 60 may serve as a potential barrier for preventing electrons, which cause a leakage current, from escaping to the second conductive type semiconductor layer 70.

The electron blocking layer 60 may be disposed on the hole injection layer 50, but the present invention is not limited thereto. The electron blocking layer 60 may be disposed on the active layer 40. The electron blocking layer 60 may be disposed between the active layer 40 and the second conductive semiconductor layer 70.

The electron blocking layer 60 may have a larger energy band gap than the barrier layer of the active layer 40.

2A, the electron blocking layer 60 may include any one of an AlGaN-based layer 61, an InAlGaN-based layer 62, and a GaN-based layer 63.

The electron blocking layer 60 may be formed of an AlGaN-based layer 61, an InAlGaN-based layer 62, and a GaN-based layer 63 in this order. The AlGaN-based layer 61, the InAlGaN-based layer 62, and the GaN-based layer 63 may be alternately arranged in a single pair.

Thus, the electron blocking layer 60 prevents electrons from escaping to the second conductive type semiconductor layer 70 by the AlGaN-based layer 61, the InAlGaN-based layer 62, and the GaN-based layer 63 The efficiency of recombination of electrons and holes in the active layer 40 can be improved to improve the luminous efficiency of the light emitting device.

The band gap energy of the InAlGaN-based layer 62 may be greater than the band gap energy of the AlGaN-based layer 61 and the GaN-based layer 63. Accordingly, the InAlGaN-based layer 62 serves as an electron barrier, and electrons supplied from the first conductivity type semiconductor layer 30 to pass through the active layer 40 to the second conductivity type semiconductor layer 70 . Therefore, the recombination rate of holes and electrons in the active layer 40 can be improved and the efficiency and efficiency of the light emitting device can be improved.

The electron blocking layer 60 may be doped with Mg. Conventionally, the electron blocking layer is continuously doped with Mg. However, when Mg is continuously doped into the electron blocking layer, the crystallinity of the electron blocking layer is lowered and segregation due to Mg may occur, thereby deteriorating the characteristics of the electron blocking layer.

Thus, in the electron blocking layer 60 according to the embodiment, the AlGaN-based layer 61 and the InAlGaN-based layer 62 are formed, doped with Mg through a heat treatment process, and then the GaN- . For example, the heat treatment may be performed at 800 to 850 캜 for 25 seconds to 35 seconds, but the present invention is not limited thereto.

Accordingly, when Mg is doped into the electron blocking layer 60 according to the embodiment, the electron blocking layer 60 can be doped with Mg without continuously doping Mg. In addition, Mg diffuses from the interface between the InAlGaN-based layer 62 and the GaN-based layer 63, so that Mg can be doped higher than the conventional Mg doping level.

For example, the Mg concentration of the electron blocking layer 60 may be highest at the interface between the InAlGaN-based layer 62 and the GaN-based layer 63. For example, the Mg concentration of the InAlGaN-based layer 62 may be lowered toward the active layer 40. For example, the Mg concentration of the GaN-based layer 63 may be lowered toward the second conductivity type semiconductor layer 70. For example, the Mg concentration of the electron blocking layer 60 may be lowered away from the interface between the InAlGaN-based layer 62 and the GaN-based layer 63. Accordingly, the doping level of Mg in the electron blocking layer 60 according to the embodiment can be increased by 2 to 3 times as compared with the case where the conventional electron blocking layer is doped with Mg. As the Mg doping level of the electron blocking layer 60 is improved, the hole injection efficiency due to the vacancy reduction of the electron blocking layer 60 is improved, and the electrical characteristics of the light emitting device can be improved.

The first conductive semiconductor layer 30 and the second conductive semiconductor layer 70 and the active layer 40 are formed by desorption of Ga in the electron blocking layer 60 by a heat treatment process before doping Mg. ) Can be improved and the reliability of the light emitting device can be improved.

Next, referring to FIG. 2B, the band gap energy of the electron blocking layer 60 may be lowered toward the active layer 40. Accordingly, stress caused by a difference in band gap energy between the active layer 40 and the electron blocking layer 60 can be reduced. Therefore, the recombination rate of electrons and holes in the active layer 40 can be increased, and the luminous efficiency and reliability of the light emitting device can be improved.

The electron blocking layer 60 may include a region having a higher bandgap energy as it approaches the second conductive semiconductor layer 70. A region of the electron blocking layer 60 that has a higher bandgap energy as it approaches the second conductive semiconductor layer 70 is a region of the electrons supplied from the first conductive semiconductor layer 30 to the active layer 40 And may serve as a barrier layer for electrons passing through the active layer 40 and escaping to the second conductivity type semiconductor layer 70 due to high mobility. Electrons supplied from the first conductivity type semiconductor layer 30 can not escape to the second conductivity type semiconductor layer 70 through the active layer 40 and electrons and holes are recombined in the active layer 40 The light emitting efficiency of the light emitting device can be improved.

In addition, the electron blocking layer 60 may include a region where the energy of the bandgap increases toward the second conductivity type semiconductor layer 70, but is suddenly lowered. Accordingly, the injection efficiency of holes supplied from the second conductive type semiconductor layer 70 can be improved, and the efficiency of recombination of electrons and holes in the active layer 40 can be increased to improve the luminous efficiency of the light emitting device.

Next, referring to FIG. 3, Reference is a characteristic of a light emitting device when a conventional electron blocking layer is applied.

As shown in FIG. 3, when the electron blocking layer according to the embodiment is applied, it can be seen that the light output (P ₀ ) is improved at a higher current level than when the conventional electron blocking layer is applied.

As described above, in the prior art, Mg is continuously doped when the electron blocking layer is formed. As a result, the crystallinity of the semiconductor layers deteriorated, causing problems in the reliability of the light emitting device, and the characteristics of the electron blocking layer could be lowered due to segregation of Mg.

Accordingly, the InAlGaN-based layer 62 is formed in the electron blocking layer 60 according to the embodiment, and the problems of the prior art can be solved by Mg delta-doping through a heat treatment process.

For example, the electron blocking layer 60 according to the embodiment may be formed by forming the AlGaN-based layer 61 and the InAlGaN-based layer 62, doping Mg after the heat treatment, and forming the GaN-based layer 63 have. For example, the heat treatment may be performed at 800 to 850 캜 for 25 seconds to 35 seconds, but the present invention is not limited thereto.

Accordingly, when Mg is doped into the electron blocking layer 60, the electron blocking layer 60 can be doped with Mg without continuously doping Mg. In addition, Mg diffuses from the interface between the InAlGaN-based layer 62 and the GaN-based layer 63, so that Mg can be doped higher than the conventional Mg doping level.

As the Mg doping level of the electron blocking layer 60 is improved, the hole injection efficiency due to the vacancy reduction of the electron blocking layer 60 is improved, and the electrical characteristics of the light emitting device can be improved.

The first conductive semiconductor layer 30 and the second conductive semiconductor layer 70 and the active layer 40 are formed by desorption of Ga in the electron blocking layer 60 by a heat treatment process before doping Mg. ) Can be improved and the reliability of the light emitting device can be improved.

Therefore, the electron blocking layer 60 of the light emitting device according to the embodiment can improve the luminous efficiency of the light emitting device by improving the hole injection efficiency and improve the crystallinity of the semiconductor layers, thereby improving the reliability of the light emitting device .

Next, referring to FIG. 4, the hole injection layer 50 of the light emitting device according to the embodiment will be described.

In the semiconductor layers of the light emitting device, a stress due to the difference in lattice constant and the orientation of the semiconductor layers may occur. This stress may cause piezoelectric polarization. Also, since the semiconductor layer has a large piezoelectric coefficient, large polarization may occur even at a small strain. Accordingly, due to the polarization, the electric field can change the energy band of the light emitting device to distort the distribution of electrons and holes. Such an effect is called a quantum confined stark effect (QCSE). It causes a low internal quantum efficiency in the emission of light generated by the recombination of electrons and holes in the light emitting device, thereby deteriorating the electrical characteristics of the light emitting device .

In order to prevent such a phenomenon, the hole injection layer 50 may be disposed on the active layer 40 according to the embodiment. The hole injection layer 50 may be disposed between the electron blocking layer 60 and the active layer 40. The hole injection layer 50 may be disposed between the active layer 40 and the second conductive semiconductor layer 70.

The hole injection layer 50 may be formed of a plurality of layers, but is not limited thereto. The hole injection layer 50 may have a lower doping concentration than the second conductivity type semiconductor layer 70. The p-type dopant may include any one of Mg, Zn, Ca, Sr, and Ba, but is not limited thereto. The hole injection layer 50 may have lower electrical conductivity than the second conductivity type semiconductor layer 70.

The hole injection layer 50 may have a smaller band gap energy than the electron blocking layer 60. The hole injection layer 50 may have the same band gap energy as the barrier layer of the active layer 40. Accordingly, the band gap energy difference between the second conductivity type semiconductor layer 70 and the active layer 40 is reduced by the hole injection layer 50 to improve the hole injection efficiency, thereby improving the luminous efficiency of the light emitting device .

The hole injection layer 50 may include a p-AlGaN-based layer 51 and a GaN-based layer 52. The p-AlGaN-based layer 51 may be disposed on the active layer 40. The p-AlGaN-based layer 51 may be disposed under the electron blocking layer 60. The p-AlGaN layer 51 may be disposed between the active layer 40 and the second conductive semiconductor layer 70. The p-AlGaN-based layer 51 may be disposed between the active layer 40 and the electron blocking layer 60.

The p-AlGaN-based layer 51 and the GaN-based layer 52 may be alternately arranged. In addition, the concentration of Al in the p-AlGaN-based layer 51 may decrease as the active layer 40 approaches. Accordingly, the resistance generated at the interface between the p-AlGaN layer 51 and the GaN layer 52 can be controlled, thereby improving the luminous efficiency of the light emitting device. In addition, the hole injection efficiency of the hole injection layer 50 can be improved by improving the diffusion efficiency of holes by the GaN-based layer 52. Thus, the luminous efficiency of the light emitting element can be improved.

The p-AlGaN-based layer 51 and the GaN-based layer 52 may be arranged in two pairs in the hole injection layer 50 as a pair. Accordingly, the hole injection efficiency can be improved by the p-AlGaN layer 51 and the GaN layer 52 to improve the luminous efficiency of the light emitting device.

The band gap energy of the p-AlGaN layer 51 may increase as the active layer 40 is closer to the active layer 40. Accordingly, the band gap energy difference between the p-AlGaN layer 51 and the active layer 40 is reduced, so that the stress due to the difference in band gap energy is alleviated and the luminous efficiency of the light emitting device can be improved.

The Al concentration of the p-AlGaN-based layer 51 may be 10%. The thickness of the p-AlGaN-based layer 51 may be 2 nm to 10 nm or less. For example, when the p-AlGaN-based layer 51 has an Al concentration of 10% or more and a thickness of 10 nm or more, the hole injection efficiency of the p-AlGaN-based layer 51 is lowered, But the present invention is not limited thereto. For example, the thickness of the p-AlGaN-based layer 51 may vary depending on the Al composition of the p-AlGaN-based layer 51, but is not limited thereto.

The GaN-based layer 52 may be an undoped semiconductor layer. The thickness of the GaN-based layer 52 may be 1 nm to 4 nm. For example, when the thickness of the GaN-based layer 52 is not 1 nm to 4 nm, the hole injection efficiency of the hole injection layer 50 may be lowered, but the present invention is not limited thereto.

The diffusion efficiency of holes injected from the second conductivity type semiconductor layer 70 into the active layer 40 is increased by the GaN layer 52 so that the luminous efficiency of the light emitting device can be improved. The GaN-based layer 52 may be AlGaN, but is not limited thereto.

Referring now to FIG. 5, Reference shows a case where a conventional hole injection layer is applied. For example, AlGraded p-AlGaN 10% shows the case where the Al concentration of the hole injection layer according to the embodiment is 10%. For example, AlGraded p-AlGaN 5% shows a case where the Al concentration of the hole injection layer according to the embodiment is 5%.

5, when the hole injection layer according to the embodiment is applied, the light output P ₀ is improved at a high current level, and the operating voltage Vf3 is decreased as compared with the case where a conventional hole injection layer is applied .

As described above, in the conventional hole injection layer, resistance is generated at the interface between the hole injection layers, so that the luminous efficiency of the light emitting device can be lowered. In addition, there is a problem that the characteristics are greatly changed due to Al compositional change of the hole injection layer 50, which is difficult to apply to a light emitting device.

However, in the hole injection layer 50 of the light emitting device according to the embodiment, the p-AlGaN-based layer 51 and the GaN-based layer 52 are alternately arranged, and the Al concentration of the p-AlGaN- The resistance that may occur at the interface between the p-AlGaN layer 51 and the GaN layer 52 can be reduced by including a region that becomes lower as the active layer 40 approaches. Accordingly, even if the Al concentration is changed in the p-AlGaN layer 51, the characteristic change is not large and the hole injection efficiency of the hole injection layer 50 can be improved, thereby improving the luminous efficiency of the light emitting device have.

Referring to FIG. 1 again, the second conductive semiconductor layer 70 may be disposed on the electron blocking layer 60. The second conductive semiconductor layer 70 may be disposed on the electron blocking layer 60. The second conductive semiconductor layer 70 may be disposed on the active layer 40.

The second conductivity type semiconductor layer 70 may be formed of at least one of a semiconductor compound, for example, a compound semiconductor of group III-V group or group II-VI compound. The second conductivity type semiconductor layer 70 may be a single layer or a multilayer. The second conductive semiconductor layer 70 may be doped with a second conductive dopant. When the second conductive semiconductor layer 70 is a p-type semiconductor layer, the second conductive dopant may include Mg, Zn, Ca, Sr, and Ba as p-type dopants.

Wherein the second conductive type semiconductor layer 70 is _{In x Al y Ga 1 -x- y} P (0≤≤x≤≤1, 0≤≤y≤≤1, 0≤≤x + y≤≤1) But is not limited to, a semiconductor material having a composition formula. For example, the second conductive semiconductor layer 70 may be formed of any one or more of AlGaP, InGaP, AlInGaP, InP, GaN, InN, AlN, InGaN, AlGaN, InAlGaN, AlInN, AlGaAs, InGaAs, AlInGaAs, .

The light emitting structure may further include another semiconductor layer on an upper surface or a lower surface of at least one of the first conductivity type semiconductor layer 30 and the second conductivity type semiconductor layer 70, but the present invention is not limited thereto. The light emitting structure may include at least one of an n-p junction, a p-n junction, an n-p-n junction, and a p-n-p junction structure depending on a lamination structure of a plurality of semiconductor layers.

The first electrode 81 may be disposed on the second conductive semiconductor layer 70. The first electrode 81 may be electrically connected to the second conductive semiconductor layer 70. The second conductive semiconductor layer 70 may be formed on at least a portion of the second conductive semiconductor layer 70. The first electrode 81 may be in direct contact with the second conductive semiconductor layer 70. The first electrode 81 may be a metal or an alloy including at least one of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Cu, Au and Hf. For example, the first electrode 81 may be formed of one of indium-tin-oxide (ITO), indium-zinc-oxide (IZO), indium-zinc- Transparent conductive materials such as Aluminum-Zinc-Oxide (IGZO), Indium-Gallium-Zinc-Oxide (IGZO), IGTO (Indium-Gallium-Tin- Oxide), AZO It may be a single layer or multiple layers of material.

A second electrode (82) may be disposed on the first conductive semiconductor layer (30). The second electrode (82) may be disposed on the exposed first conductivity type semiconductor layer (30). The second electrode 82 may be disposed on at least a part of the first conductive semiconductor layer 30. The second electrode 82 may be electrically connected to the first conductive semiconductor layer 30. The second electrode (82) may be in direct contact with the first conductive semiconductor layer (30).

For example, the second electrode 82 may be a metal or an alloy including at least one of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Cu, Au and Hf. The second electrode 82 may be formed of a metal or an alloy of ITO (Indium-Tin-Oxide), IZO (Indium-Zinc-Oxide), IZTO (Indium-Zinc-Tin-Oxide), IAZO (Indium- A single layer of a transparent conductive material such as IGZO (Indium-Gallium-Zinc-Oxide), IGTO (Indium-Gallium-Tin-Oxide), Aluminum-Zinc-Oxide (AZO) May be multi-layered.

As described above, in the hole injection layer of the conventional art, resistance is generated at the interface between the hole injection layers, and the luminous efficiency of the light emitting device may be lowered. In addition, there is a problem that it is difficult to apply the present invention to a light emitting device due to a large change in characteristics due to Al compositional change of the hole injection layer.

However, in the light emitting device according to the embodiment, the p-AlGaN-based layer 51 and the GaN-based layer 52 are alternately arranged in the hole injection layer 50 and the Al concentration of the p-AlGaN- The resistance that may occur at the interface between the p-AlGaN-based layer 51 and the GaN-based layer 52 is reduced by lowering the operating voltage of the light-emitting device by decreasing the closer to the active layer 40 You can. In addition, the hole injection layer 50 of the light emitting device according to the embodiment improves the hole injection efficiency of the hole injection layer 50 even when the Al concentration changes in the p-AlGaN layer 51, And the light emitting efficiency of the light emitting device is improved.

The electron blocking layer of the prior art was formed by continuously doping Mg when forming the electron blocking layer. As a result, the crystallinity of the semiconductor layers deteriorated, causing problems in the reliability of the light emitting device, and the characteristics of the electron blocking layer could be lowered due to segregation of Mg.

However, the electron blocking layer 60 of the light emitting device according to the embodiment may be reduced in vacancy of the electron blocking layer 60 by Mg delta doping and heat treatment process to improve the hole injection efficiency, Can be improved. The crystallinity of the first conductivity type semiconductor layer 30, the second conductivity type semiconductor layer 70 and the active layer 40 due to the desorption of Ga in the electron blocking layer 60 by the heat treatment The reliability of the light emitting device can be improved. And, the Mg doping level can be increased by 2 to 3 times compared to the prior art by Mg delta doping.

6 to 8 are cross-sectional views illustrating a manufacturing process of the light emitting device according to the embodiment.

First, the substrate 10 may be prepared as shown in FIG. The substrate 10 may be formed of a material having excellent thermal conductivity, and may be a conductive substrate or an insulating substrate.

For example, at least one of GaAs, sapphire (Al ₂ O ₃ ), SiC, Si, GaN, ZnO, GaP, InP, Ge and Ga ₃ may be used for the substrate 10. A concave-convex structure is formed on the substrate 10 to improve light extraction efficiency, but a concavo-convex structure is not essential. The substrate 10 may be wet-cleaned to remove impurities on the surface.

On the substrate 10, an undoped semiconductor layer 20 may be formed. The undoped semiconductor layer 20 may mitigate lattice mismatching between the subsequently formed light emitting structure and the substrate 10.

Thereafter, the first conductive semiconductor layer 30 and the active layer 40 may be formed on the substrate 10 or the unshown semiconductor layer 20.

The first conductive semiconductor layer 30 may be formed of a semiconductor compound, for example, a Group III-V-V, a Group VI-VI, or the like, and may be doped with a first conductive dopant. For example, when the first conductive semiconductor layer 30 is an n-type semiconductor layer, it may include Si, Ge, Sn, Se, and Te as an n-type dopant. Wherein the first conductive type semiconductor layer 30 is _{In x Al y Ga 1 -x- y} N (0≤≤x≤1, 0≤≤y≤≤1, 0≤≤x + y≤≤1) the composition formula And the like. For example, the first conductive semiconductor layer 30 may be formed of one or more of GaN, InN, AlN, InGaN, AlGaN, InAlGaN, AlInN, AlGaAs, InGaAs, AlInGaAs, GaP, AlGaP, InGaP, AlInGaP, .

The first conductive semiconductor layer 30 may be formed by a chemical vapor deposition (CVD) method, a molecular beam epitaxy (MBE) method, a sputtering method, or a vapor phase epitaxy (HVPE) method. .

Then, the active layer 40 may be formed on the first conductive semiconductor layer 30.

Electrons injected through the first conductive type semiconductor layer 30 and holes injected through the second conductive type semiconductor layer 70 formed after the first and second conductive type semiconductor layers 70 and 70 are in contact with each other to form an energy band unique to the active layer Which emits light having an energy determined by < RTI ID = 0.0 >

The active layer 40 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.

The active layer 40 may include a quantum well / quantum wall structure. For example, the active layer 40 may be formed of any one or more pairs of InGaN / GaN, InGaN / InGaN, GaN / AlGaN, InAlGaN / GaN, GaAs / AlGaAs, InGaP / AlGaP and GaP / AlGaP. It does not.

Next, as shown in FIG. 7, a hole injection layer 50 and an electron blocking layer 60 may be formed on the active layer 40.

Hereinafter, the technical features of the light emitting device according to the embodiment will be described with reference to FIGS. 1 to 5. FIG.

2A, 2B, and 3, the electron blocking layer 60 of the light emitting device according to the embodiment is reduced in vacancy of the electron blocking layer 60 by Mg delta doping and heat treatment, The injection efficiency can be improved and the electrical characteristics of the light emitting device can be improved. The crystallinity of the first conductivity type semiconductor layer 30, the second conductivity type semiconductor layer 70 and the active layer 40 due to the desorption of Ga in the electron blocking layer 60 by the heat treatment The reliability of the light emitting device can be improved. And, the Mg doping level can be increased by 2 to 3 times compared to the prior art by Mg delta doping.

4 and 5, in the light emitting device according to the embodiment, the p-AlGaN-based layer 51 and the GaN-based layer 52 are alternately arranged in the hole injection layer 50, and the p-AlGaN AlGaN-based layer 51 and the GaN-based layer 52 are reduced by decreasing the resistance of the p-AlGaN-based layer 51 and the GaN-based layer 52, And the hole injection efficiency of the hole injection layer 50 can be improved without changing the characteristics even when the Al concentration is changed in the p-AlGaN layer 51, There is an effect to be improved.

Next, as shown in FIG. 7, a second conductive semiconductor layer 70 may be formed on the electron blocking layer 60.

The second conductive semiconductor layer 70 may be formed of a semiconductor compound. For example, the second conductive semiconductor layer 70 may be formed of a compound semiconductor such as a Group III-V, a Group VI-VI, or the like, and may be doped with a second conductive dopant.

For example, the second conductive type semiconductor layer 70 is the second conductive type dopant is doped -5-group three-V compound semiconductor, for example, In _x Al _y Ga _{1 -x- y} N (0≤≤x≤ 1, 0? Y? 1, 0? X + y? 1). For example, when the second conductive semiconductor layer 70 is a p-type semiconductor layer, the second conductive dopant may include Mg, Zn, Ca, Sr, and Ba as p-type dopants.

For example, the second conductivity type semiconductor layer 70 may be formed by depositing a p-type impurity such as trimethyl gallium gas (TMGa), ammonia gas (NH3), nitrogen gas (N2), and magnesium (Mg) butyl cyclopentadienyl magnesium _{(EtCp 2 Mg) {Mg (} C 2 H 5 C 5 H) 2} is injected may be a p-type GaN layer formed, but the embodiment is not limited thereto.

The first conductive semiconductor layer 30 may be an n-type semiconductor layer, and the second conductive semiconductor layer 70 may be a p-type semiconductor layer. However, the present invention is not limited thereto. Also, on the second conductive semiconductor layer 70, a semiconductor (e.g., an n-type semiconductor layer) (not shown) having a polarity opposite to that of the second conductive type may be formed. Accordingly, the light emitting structure 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. 8, a first electrode 81 may be formed on the second conductive type semiconductor layer 70.

In addition, the second electrode 82 may be formed on the exposed first conductive semiconductor layer 30 to manufacture the light emitting device according to the embodiment.

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

9, the light emitting device package 1000 includes a package body 1100, a first electrode 1200 and a second electrode 1300 disposed on the package body 1100, A light emitting device 100 disposed on the first electrode 1200 and electrically connected to the first electrode 1200 and the second electrode 1300 and a molding member 1400 surrounding the light emitting device 100 have.

The package body 1100 may include a silicon material, a synthetic resin material, or a metal material. The package body 1100 may have a sloped surface formed on a side surface of the light emitting device.

The first electrode 1200 and the second electrode 1300 may be electrically isolated from each other. The first electrode 1200 and the second electrode 1300 may provide power to the light emitting device 100. The first electrode 1200 and the second electrode 1300 may reflect light emitted from the light emitting device 100 to increase light efficiency. The first electrode 1200 and the second electrode 1300 may serve to discharge heat generated in the light emitting device 100 to the outside.

The light emitting device 100 may be disposed on the package body 1100. The light emitting device 100 may be disposed on the first electrode 1200 or the second electrode 1300.

The light emitting device 100 may be electrically connected to the first electrode 1200 and / or the second electrode 1300 by a wire, a flip chip, or a die bonding method. In the exemplary embodiment of the present invention, the light emitting device 100 is electrically connected to the first electrode 1200 and the second electrode 1300 through wires, but the present invention is not limited thereto.

In addition, the molding member 1400 surrounds the light emitting device 100 to protect the light emitting device 100. The molding member 1400 may include a phosphor. The phosphor included in the molding member 1400 may change the wavelength of the light emitted from the light emitting device 100.

The above-described light emitting device is constituted by a light emitting device package and can be used as a light source of an illumination system, for example, as a light source of an image display device or a light source of an illumination device.

Next, Fig. 10 is an exploded perspective view of the illumination device according to the embodiment.

10, the lighting apparatus according to the embodiment includes a cover 2100, a light source module 2200, a heat discharger 2400, a power supply unit 2600, an inner case 2700, 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.

When the light emitting device according to the embodiment is used as a backlight unit of an image display device, it can be used as an edge type backlight unit or as a direct-type backlight unit, and can be used as a regulator or a bulb type when used as a light source of a lighting device, It may also be used as a light source of a mobile terminal.

The light emitting element includes a laser diode in addition to the light emitting diode described above.

The laser diode may include the first conductivity type semiconductor layer, the active layer and the second conductivity type semiconductor layer having the above-described structure, like the light emitting element. Then, electro-luminescence (electroluminescence) phenomenon in which light is emitted when an electric current is applied after bonding the p-type first conductivity type semiconductor and the n-type second conductivity type semiconductor is used, And phase. That is, the laser diode can emit light having one specific wavelength (monochromatic beam) with the same phase and in the same direction by using a phenomenon called stimulated emission and a constructive interference phenomenon. It can be used for optical communication, medical equipment and semiconductor processing equipment.

As the light receiving element, a photodetector, which is a kind of transducer that detects light and converts the intensity of the light into an electric signal, is exemplified. As such a photodetector, a photodiode (e.g., a PD with a peak wavelength in a visible blind spectral region or a true blind spectral region), a photodiode (e.g., a photodiode such as a photodiode (silicon, selenium), a photoconductive element (cadmium sulfide, cadmium selenide) , Photomultiplier tube, phototube (vacuum, gas-filled), IR (Infra-Red) detector, and the like.

In addition, a semiconductor device such as a photodetector may be fabricated using a direct bandgap semiconductor, which is generally excellent in photo-conversion efficiency. Alternatively, the photodetector has a variety of structures, and the most general structure includes a pinned photodetector using a pn junction, a Schottky photodetector using a Schottky junction, and a metal-semiconductor metal (MSM) photodetector have.

The photodiode, like the light emitting device, may include the first conductivity type semiconductor layer having the structure described above, the active layer, and the second conductivity type semiconductor layer, and may have a pn junction or a pin structure. The photodiode operates by applying reverse bias or zero bias. When light is incident on the photodiode, electrons and holes are generated and a current flows. At this time, the magnitude of the current may be approximately proportional to the intensity of the light incident on the photodiode.

A photovoltaic cell or a solar cell is a type of photodiode that can convert light into current. The solar cell, like the light emitting device, may include the first conductivity type semiconductor layer, the active layer and the second conductivity type semiconductor layer having the above-described structure.

In addition, it can be used as a rectifier of an electronic circuit through a rectifying characteristic of a general diode using a p-n junction, and can be applied to an oscillation circuit or the like by being applied to a microwave circuit.

In addition, the above-described semiconductor element is not necessarily implemented as a semiconductor, and may further include a metal material as the case may be. For example, a semiconductor device such as a light receiving element may be implemented using at least one of Ag, Al, Au, In, Ga, N, Zn, Se, P, or As, Or may be implemented using a doped semiconductor material or an intrinsic semiconductor material.

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

10: substrate 20: unselected semiconductor layer 30: first conductivity type semiconductor layer
40: active layer 50: hole injection layer 60: electron blocking layer
70: second conductive type semiconductor layer

Claims (10)

Board; And
A light emitting structure disposed on the substrate,
The light-
An active layer disposed between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer; And
An InAlGaN-based layer alternately disposed between the active layer and the second conductive type semiconductor layer; and an electron blocking layer including an AlGaN-based layer and a GaN-based layer,
Wherein the electron blocking layer includes a region where a band gap energy decreases as the active layer approaches the active layer and a region where bandgap energy increases as the second conductive semiconductor layer approaches the active layer. The method according to claim 1,
And the magnesium concentration of the electron blocking layer decreases as the distance from the interface between the InAlGaN-based layer and the GaN-based layer decreases. 3. The method of claim 2,
Wherein the InAlGaN-based layer has a lower concentration of magnesium as the active layer is closer to the active layer. 3. The method of claim 2,
And the magnesium concentration of the electron blocking layer is highest at the interface between the InAlGaN-based layer and the GaN-based layer. The method according to claim 1,
And the band gap energy of the InAlGaN-based layer is higher than the band gap energy of the AlGaN-based layer and the GaN-based layer. The method according to claim 1,
And a hole injection layer disposed between the second conductivity type semiconductor layer and the active layer and including a p-AlGaN-based layer and a GaN-based layer. The method according to claim 6,
The p-AlGaN-based layer includes a region where the Al concentration decreases as the active layer approaches the active layer. The method according to claim 6,
Wherein the p-AlGaN-based layer includes a region where the Al concentration increases as the layer is closer to the second conductivity type semiconductor layer. The method according to claim 6,
Wherein the p-AlGaN-based layer includes a region where bandgap energy increases as the active layer approaches the active layer. A lighting device comprising a light-emitting unit comprising a light-emitting element according to any one of claims 1 to 9.

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