KR20180087678A - Semiconductor Device And Light Apparatus - Google Patents

Abstract

An embodiment relates to a semiconductor device and a lighting device. According to the embodiment, the light emitting device comprises: a first semiconductor layer including a first superlattice layer of a first conductivity type, having an In_(x-)Ga_(1-x)N/GaN (0 < x < 1) composition, and a semiconductor layer of the first conductivity type; a second superlattice layer disposed on the first semiconductor layer, and having an In_yGa_(1-y)N/GaN (0 < y < 1) composition; an active layer disposed on the second superlattice layer; and a second semiconductor layer disposed on the active layer. The indium concentration of the first superlattice layer of a first conductivity type is lower than the indium concentration of the second superlattice layer. In the light emitting device according to the embodiment, the first semiconductor layer may include the first superlattice layer of a first conductivity type. Accordingly, the crystallinity of the first semiconductor layer is relieved, and thus the stress caused by the lattice mismatch between the first semiconductor layer and the active layer can be reduced. Therefore, the semiconductor device and the lighting device of the embodiment have the first semiconductor layer, which includes the first superlattice layer of a first conductivity type, to relieve the stress generated at the interface between the first semiconductor layer and the active layer, thereby improving luminous efficiency of the light emitting device.

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.

At this time, a stress is generated in the active layer due to a difference in lattice constant between the semiconductor layers and the active layer, and the recombination probability of electrons and holes may be lowered. Accordingly, the light characteristic of the light emitting device is degraded due to the stress generated in the active layer, which may lead to optical reliability problems of the light emitting device.

Embodiments provide a semiconductor device and a lighting device capable of reducing a stress generated in the active layer due to a difference in lattice constant between a semiconductor layer and an active layer.

Embodiments provide a semiconductor device and a lighting device capable of reducing the stress generated in the active layer to improve optical characteristics.

The light emitting device according to the embodiment includes a first superlattice layer of a first conductivity type having a composition of In _{x -} Ga _{1 - x} N / GaN (0 <x <1) and a first semiconductor layer And a second super lattice layer having a composition of In _y Ga _1-y N / GaN (0 <y <1) on the first semiconductor layer, an active layer on the second super lattice layer, Layer, and the indium concentration of the first superlattice layer of the first conductivity type may be lower than the indium concentration of the second superlattice layer.

In the light emitting device according to the embodiment, the second superlattice layer 40 having the composition of In _y Ga _{1 - y} N / GaN (0 <y <1) may not be doped with the first conductivity type dopant.

The indium composition of the first super lattice layer of the first conductivity type of the light emitting device according to the embodiment may be 5% or less.

The thickness of the first super lattice layer of the first conductivity type of the light emitting device according to the embodiment may be 5 to 20 nm.

The first semiconductor layer of the light emitting device according to the embodiment may be alternately arranged with the first superlattice layer of the first conductivity type and the first conductivity type semiconductor layer.

The indium concentration of the second superlattice layer of the In _y Ga _{1 - y} N / GaN (0 <y <1) composition of the light emitting device according to the embodiment may be lower than the indium concentration of the active layer.

The first superlattice layer of the first conductivity type of the light emitting device according to the embodiment may include either a dot shape or a layered shape 32a.

For the embodiment may further include the first semiconductor layer forms a dot of a first conductivity type third layer superlattice having _{In z Ga 1 -z N / GaN} (0 <z <1) the composition of the light emitting device according to.

The diameter size of the dot shape of the third superlattice layer of the first conductivity type of the light emitting device according to the embodiment may be 10 to 100 nm.

The third superlattice layer of the first conductivity type having a dot shape of the light emitting device according to the embodiment may be disposed lower than the first superlattice layer of the first conductivity type.

The embodiment can provide a semiconductor device and a lighting device capable of relieving stress generated in the active layer.

Embodiments can provide a semiconductor device and a lighting device that can control the crystallinity of the semiconductor layer to relieve the stress generated in the active layer.

Embodiments can provide a semiconductor device and a lighting device in which the stress generated in the active layer is relaxed to increase the probability of recombination of electrons and holes in the active layer to improve optical characteristics.

1 is a cross-sectional view of a light emitting device according to a first embodiment.
2 is a cross-sectional view of a first semiconductor layer of the light emitting device according to the first embodiment.
3 is a cross-sectional view of a light emitting device according to the second embodiment.
4 is a cross-sectional view of a light emitting device according to a third embodiment.
5 is a graph illustrating internal quantum efficiency of a light emitting device according to an 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 an 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 and the light emitting device 100 according to the embodiment as shown in Figure 2 includes a substrate 10, the undoped conductive semiconductor layer 20, the first conductive type semiconductor layer 31 and the In _{x -} Ga _{1 - x N / GaN (0 <x} <1) a first conductivity type first superlattice layers (32a, 32b) comprising: a first semiconductor layer 30 and the second semiconductor layer 70 and active layer (50 containing the composition ), the light emitting structure, in _y Ga ₁ comprising a _{- y N / GaN (0 <} y <1) second superlattice layer 40 of the composition, an electron blocking layer 60, a first electrode 81, the second Electrode 82 as shown in FIG.

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, 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 unshown semiconductor layer 20 may have a lower electrical conductivity than the first semiconductor layer 30 or the second semiconductor layer 70 because the conductivity type dopant is not doped.

The first semiconductor layer 30 may be disposed on the undoped semiconductor layer 20. A second superlattice layer (40) may be disposed under the first semiconductor layer (30). The first semiconductor layer 30 may be disposed between the undoped semiconductor layer 20 and the second superlattice layer 40. For example, the thickness of the first semiconductor layer 30 may be 50-200 nm.

The first semiconductor layer 30 includes a first conductive type semiconductor layer 31 doped with a first conductive type dopant and a first superlattice layer 32a of a first conductive type doped with a first conductive type dopant can do. The first semiconductor layer 30 may include at least one or more of the first conductive semiconductor layers 31. The first semiconductor layer 30 may include at least one first superlattice layer 32a of the first conductivity type.

The first conductive semiconductor layer 31 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 31 may be a single layer or a multilayer. The first conductive semiconductor layer 31 may be doped with a first conductive dopant. For example, when the first conductive semiconductor layer 31 is an n-type semiconductor layer, it may include an n-type dopant. For example, the n-type dopant may include but is not limited to Si, Ge, Sn, Se, and Te. For example, the first conductive type semiconductor layer 31 is _{In x Al y Ga 1 -x- y} P (0≤≤x≤≤1, 0≤≤y≤≤1, 0≤≤x + y≤ Lt; = 1). However, the present invention is not limited thereto. For example, the first conductive semiconductor layer 31 may be formed of any one or more of AlGaP, InGaP, AlInGaP, InP, GaN, InN, AlN, InGaN, AlGaN, InAlGaN, AlInN, AlGaAs, InGaAs, AlInGaAs, . For example, the indium composition of the first conductivity type semiconductor layer 31 may be 5% or less.

The first superlattice layer 32a of the first conductivity type may be disposed on the undoped semiconductor layer 20. The first superlattice layer 32a of the first conductivity type may be disposed under the second superlattice layer 40. [ The first superlattice layer 32a of the first conductivity type may be disposed between the second superlattice layer 40 and the undoped semiconductor layer 20. The thickness of the first superlattice layer 32a of the first conductivity type may be 5 to 20 nm. For example, if the thickness of the first superlattice layer 32a of the first conductivity type is not 5 to 20 nm, the crystallinity of the first semiconductor layer 30 may be affected to decrease the luminous efficiency of the light emitting device But is not limited thereto.

For example, the composition of the first conductive type first superlattice layers (32a) is of In _{x -} may be a _{Ga 1 -x N / GaN (0} <x <1). The indium composition of the first superlattice layer 32a of the first conductivity type may be 5% or less. For example, when the indium composition of the first superlattice layer 32a of the first conductivity type is 5% or more, the crystallinity of the first semiconductor layer 30 is affected and the luminous efficiency of the light emitting device may decrease However, the present invention is not limited thereto.

The indium composition of the first superlattice layer 32a of the first conductivity type may be lower than the indium concentration of the second superlattice layer 40. [ Accordingly, the first superlattice layer 32a of the first conductivity type does not form a separate layer like the second superlattice layer 40, and the crystallinity of the first semiconductor layer 30 is controlled by the first superlattice layer 32a of the first conductivity type. The stress generated in the active layer 50 and the first semiconductor layer 30 can be controlled.

In addition, the first semiconductor layer 30 may be formed of a pair of the first conductive semiconductor layer 31 and the first superlattice layer 32a of the first conductivity type. For example, when the first conductive semiconductor layer 31 and the first superlattice layer 32a of the first conductivity type are disposed in pairs, the first conductivity type semiconductor layer 31 and the first The first superlattice layer 32a of the conductive type may be formed in 10 pairs to 50 pairs.

For example, when the first conductive semiconductor layer 31 and the first superlattice layer 32a of the first conductive type are less than 10 pairs, the first semiconductor layer 30 and the active layer 50 The stress generated in the active layer 50 may increase due to the lattice mismatch, thereby lowering the luminous efficiency of the light emitting device. However, the present invention is not limited thereto.

For example, when the first conductive semiconductor layer 31 and the first superlattice layer 32a of the first conductivity type are over 50 pairs, the crystallinity of the first semiconductor layer 30 is affected The light emitting efficiency of the light emitting device may be lowered, but the present invention is not limited thereto.

In the light emitting device, light is generated by recombination of electrons and holes supplied from the n-type semiconductor layer and the p-type semiconductor layer in the active layer. Accordingly, the luminous efficiency of the light emitting device can be changed according to the internal state of the active layer.

In the prior art, after the n-type semiconductor layer is formed, the active layer and the p-type semiconductor layer are formed, and stress may be generated in the active layer due to a difference in lattice constant between the respective semiconductor layers and the active layer. Therefore, the probability of recombination of electrons and holes in the active layer may be lowered due to the stress generated in the active layer. As a result, the luminous efficiency of the light emitting element can be lowered. Accordingly, a separate strain relief layer is formed between the semiconductor layer and the active layer to minimize the stress caused by the lattice mismatch between the semiconductor layer and the active layer, thereby improving the recombination probability of electrons and holes in the active layer, thereby improving the luminous efficiency of the light emitting device I could.

However, in the light emitting device according to the embodiment, a first superlattice layer 32a of the first conductivity type and a first superlattice layer 32a of the first conductivity type semiconductor layer 31 are formed in the first semiconductor layer 30, The crystallinity of the first semiconductor layer 30 is controlled to minimize the stress generated by the lattice mismatch between the first semiconductor layer 30 and the active layer 50, Can be improved.

In the light emitting device 100 according to the first embodiment, the first semiconductor layer 30 includes the first superlattice layer 32a of the first conductivity type, 1 semiconductor layer 30, as shown in FIG. Accordingly, the stress generated in the active layer 50 due to the difference in lattice constant between the first semiconductor layer 30 and the active layer 50 can be alleviated.

As described above, in the light emitting device 100 according to the first embodiment, the first superlattice layer 32a of the first conductivity type absorbs stress due to the lattice constant difference in the first semiconductor layer 30, The light emitting efficiency of the light emitting device 100 can be improved by improving the probability of recombination of electrons and holes in the active layer 50 by reducing the stress generated in the active layer 50.

A second superlattice layer (40) may be disposed on the first semiconductor layer (30). The second superlattice layer 40 may be disposed on the first conductive semiconductor layer 31. The second superlattice layer (40) may be disposed on the first superlattice layer (32a) of the first conductivity type. The second superlattice layer 40 may be disposed between the first semiconductor layer 30 and the active layer 50. The second superlattice layer 40 may be disposed between the first conductive semiconductor layer 31 and the active layer 50. The second superlattice layer 40 may be disposed between the first superlattice layer 32a of the first conductivity type and the active layer 50. For example, the composition of the second superlattice layer 40 may be In _y Ga _{1 -yN} / GaN (0 <y <1), but is not limited thereto.

Also, the second superlattice layer 40 may not be doped with the first conductive type dopant. Accordingly, the strain relief effect of the second superlattice layer 40 can be generated by forming a layer separately.

The second superlattice layer 40 may have a larger lattice constant than the first semiconductor layer 30. The second superlattice layer 40 may have a smaller lattice constant than the active layer 50. The second superlattice layer 40 may have a lattice constant larger than that of the first semiconductor layer 30 and smaller than that of the active layer 50.

For example, the second superlattice layer 40 has a lattice constant larger than that of the first semiconductor layer 30 and smaller than that of the active layer 50, so that the first semiconductor layer 30 and the active layer 50 are formed. The strain applied to the active layer 50 can be relaxed by the lattice mismatch.

The second superlattice layer 40 may have a larger lattice constant than the first superlattice layer 32a of the first conductivity type. The second superlattice layer 40 may have a smaller lattice constant than the active layer 50. The second superlattice layer 40 may have a lattice constant larger than that of the first superlattice layer 32a of the first conductivity type and smaller than that of the active layer 50.

For example, the second superlattice layer 40 has a larger lattice constant than the first superlattice layer 32a of the first conductivity type and has a smaller lattice constant than the active layer 50, The strain applied to the active layer 50 by the lattice mismatching between the first superlattice layer 32a and the active layer 50 can be relaxed.

Accordingly, the second superlattice layer 40 can effectively relax the strain due to the lattice mismatch between the first semiconductor layer 30 and the active layer 50.

The second superlattice layer 40 may have a stack of In _y Ga _{1 - y} N / GaN (0 <y <1). The indium composition of the second superlattice layer 40 may be 5-10%. For example, the thickness of the second superlattice layer 40 may be 50-300 nm, but is not limited thereto.

For example, the indium concentration of the second superlattice layer 40 may be lower than the indium concentration of the active layer 50. The indium concentration of the second superlattice layer 40 may be higher than the indium concentration of the first semiconductor layer 30. The band gap energy difference between the active layer 50 and the second superlattice layer 40 is smaller than the band gap energy difference between the active layer 50 and the first semiconductor layer 30, The layer 40 may mitigate stress due to band gap energy differences, but is not limited thereto.

For example, when the thickness of the second superlattice layer 40 is 50 to 300 nm and the composition of indium is not 5 to 10%, the second superlattice layer 40 may be generated in the active layer 50 The light emitting efficiency of the light emitting device may be lowered.

The active layer 50 may be disposed on the second superlattice layer 40. In the active layer 50, electrons (or holes) injected through the first semiconductor layer 30 and holes (or electrons) injected through the second semiconductor layer 70 may meet with each other. The active layer 50 may emit light due to a difference in bandgap of an energy band according to the material of the active layer 50 due to the presence of electrons and holes. The active layer 50 may emit at least one of ultraviolet light, blue light, green light, and red light.

The active layer 50 may optionally include a single quantum well, a multiple quantum well (MQW), a quantum wire structure, or a quantum dot structure. The active layer 50 may be composed of a compound semiconductor. The active layer 50 may be formed of at least one of Group 3-Group-5 or Group-6-Group compound semiconductors.

The active layer 50 may include a quantum well layer and a quantum barrier layer. When the active layer 50 is implemented as a multiple quantum well structure, the quantum well layer and the quantum barrier layer may be alternately arranged. For example, the quantum well layer and the quantum barrier layer is _{In x Al y Ga 1 -x- y} P (0≤≤x≤≤1, 0≤≤y≤≤1, 0≤≤x + y≤≤ each GaN / AlGaIn, InGaP / AlGaP, InGaN / GaN, InGaN / InGaN, GaN / AlGaN, InAlGaN / GaN, GaAs / AlGaAs and InGaAs / AlGaAs. 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.

An electron blocking layer 60 may be disposed on the active layer 50. The electron blocking layer 60 may be disposed under the second semiconductor layer 70. The electron blocking layer 60 relaxes the piezoelectric polarization effect between the active layer 50 and the second semiconductor layer 70 so that the hole injection efficiency to be injected into the active layer 50 from the second semiconductor layer 70 Can be improved. Accordingly, the luminous efficiency of the light emitting device 100 can be improved.

For example, the electron blocking layer 60 may be formed to a thickness of 20 nm to 100 nm. If the thickness of the electron blocking layer 60 is less than 20 nm, the piezoelectric polarization of the second semiconductor layer 70 and the active layer 50 may not be relaxed. When the thickness of the electron blocking layer 60 is greater than 100 nm, the injection efficiency of holes supplied from the second semiconductor layer 70 to the active layer 50 may be lowered, but the present invention is not limited thereto.

For example, the electron blocking layer 60 may have a structure of InGaN / GaN. For example, when the electron blocking layer 60 is made of InGaN / GaN, the composition of indium may be 10-15%.

A second semiconductor layer 70 may be disposed on the electron blocking layer 60. The second semiconductor layer 70 may be formed of at least one of a semiconductor compound, for example, a group III-V group compound or a group II-VI compound semiconductor. The second semiconductor layer 70 may be a single layer or a multi-layered structure. The second semiconductor layer 70 may be doped with a second conductive dopant. For example, when the second semiconductor layer 70 is a p-type semiconductor layer, the second conductive dopant may include Mg, Zn, Ca, Sr, and Ba as a p-type dopant.

For example, the second semiconductor layer 70 is _{In x Al y Ga 1 -x- y} P (0≤≤x≤≤1, 0≤≤y≤1, 0≤≤x + y≤≤1) But it is not limited thereto. For example, the second 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, have.

A first electrode (81) may be disposed on the second semiconductor layer (70). The first electrode (81) may be electrically connected to the second semiconductor layer (70). The second semiconductor layer 70 may be formed on at least a part of the second semiconductor layer 70. The first electrode 81 may be in direct contact with the second 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 semiconductor layer (30). The second electrode (82) may be disposed on the exposed first semiconductor layer (30). The second electrode 82 may be disposed on at least a part of the first semiconductor layer 30. The second electrode (82) may be electrically connected to the first semiconductor layer (30). The second electrode (82) may be in direct contact with the first semiconductor layer (30).

The second electrode 82 may be disposed on the first conductive semiconductor layer 31. The second electrode (82) may be disposed on at least a part of the first conductive type semiconductor layer (31). The second electrode 82 may be electrically connected to the first conductive semiconductor layer 31. The second electrode 82 may be disposed on a side surface of the first conductive semiconductor layer 31.

The second electrode 82 may be disposed on the first superlattice layer 32a of the first conductivity type. The second electrode 82 may be disposed on at least a part of the first conductive superlattice layer 32a. The second electrode 82 may be electrically connected to the first superlattice layer 32a of the first conductivity type. The second electrode 82 may be disposed on a side surface of the first superlattice layer 32a of the first conductivity type.

The second electrode 82 may be disposed on the side of the second superlattice layer 40.

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.

The light emitting device in the prior art forms an active layer and a p-type semiconductor layer after forming an n-type semiconductor layer, and stress may be generated in the active layer due to a difference in lattice constant between the respective semiconductor layers and the active layer. Therefore, the probability of recombination of electrons and holes in the active layer may be lowered due to the stress generated in the active layer. As a result, the luminous efficiency of the light emitting element can be lowered.

Accordingly, a separate strain relief layer is formed between the semiconductor layer and the active layer to minimize the stress caused by the lattice mismatch between the semiconductor layer and the active layer, thereby improving the recombination probability of electrons and holes in the active layer, thereby improving the luminous efficiency of the light emitting device I could.

However, in the light emitting device according to the embodiment, the first superlattice layer 32a of the first conductivity type and the first superlattice layer 32b of the first conductivity type are not formed between the semiconductor layer and the active layer, Type semiconductor layers 31 are alternately arranged to control the crystallinity of the first semiconductor layer 30 to minimize the stress caused by the lattice mismatch between the first semiconductor layer 30 and the active layer 50 Emitting efficiency of the light-emitting element can be improved.

In the light emitting device 100 according to the first embodiment, the first semiconductor layer 30 includes the first superlattice layer 32a of the first conductivity type to control the crystallinity of the first semiconductor layer 30 can do. Accordingly, the stress generated in the active layer 50 due to the difference in lattice constant between the first semiconductor layer 30 and the active layer 50 can be alleviated.

As described above, in the light emitting device 100 according to the first embodiment, the lattice constant difference between the first semiconductor layer 30 and the active layer 50 due to the first superlattice layer 32a of the first conductivity type The stress generated by the first semiconductor layer 30 can be absorbed by the first semiconductor layer 30 and the stress generated in the active layer 50 is reduced to improve the probability of recombination of electrons and holes in the active layer 50, The luminous efficiency of the device 100 can be improved.

Next, Fig. 3 is a cross-sectional view of the light emitting device according to the second embodiment.

3, the first semiconductor layer 30 of the light emitting device according to the second embodiment includes either the first conductive type semiconductor layer 31 and the first superlattice layer 32b of the first conductivity type One can be included.

In the light emitting device according to the second embodiment of FIG. 3, the description of the light emitting device according to the first embodiment shown in FIG. 1 can be adopted. In the following, the main features of the second embodiment will be described.

In FIG. 3, the first superlattice layer 32b of the first conductivity type included in the first semiconductor layer 30 may be arranged in a dot shape. The crystallinity of the first semiconductor layer 30 is controlled by the dot-shaped first conductive superlattice layer 32b so that the active layer 50 and the lattice of the first semiconductor layer 30 The stress generated in the active layer 50 by the mismatching can be alleviated and the luminous efficiency of the light emitting device can be improved. In addition, light emitted from the active layer 50 is scattered by the dot-shaped first superlattice layer 32b of the first conductivity type, so that light extraction efficiency of the light emitting device can be improved.

For example, when the first superlattice layer 32b of the first conductivity type is disposed in the form of a dot, the diameter size of the dot may be 10 to 100 nm. For example, when the diameter of the dots of the first superlattice layer 32b of the first conductivity type is not 10 nm to 100 nm, the first superlattice layer 32b of the first conductivity type The light scattering effect may deteriorate and the luminous efficiency of the light emitting device may be lowered. However, the present invention is not limited to this.

3, in the light emitting device according to the second embodiment, the first superlattice layer 32b of the first conductivity type of the first semiconductor layer 30 is formed in a dot shape, The light emitted from the active layer 50 is scattered due to the first superlattice layer 32a of the first conductivity type formed in a dot shape to reduce the light extraction efficiency of the light emitting device 100 Can be improved.

4 is a cross-sectional view of a light emitting device according to the third embodiment,

Referring to FIG. 4, the first semiconductor layer 30 of the light emitting device according to the third embodiment includes a first conductive semiconductor layer 31, a first superlattice layer 32a of a first conductivity type, And a third superlattice layer 32c of one conductivity type.

In the light emitting device according to the third embodiment of FIG. 4, the description of the light emitting device according to the first embodiment and the second embodiment shown in FIGS. 1 and 2 can be adopted. In the following, Features will be described.

As shown in FIG. 4, the first semiconductor layer 30 of the light emitting device according to the third embodiment has the first semiconductor layer 30 and the first superlattice layer 32a of the first conductivity type, And a third superlattice layer 32c of the first conductivity type. For example, the composition of the third superlattice layer 32c of the first conductivity type may be In _z Ga _{1 - z} N / GaN (0 <z <1), but is not limited thereto.

Accordingly, the stress applied to the active layer 50 by the first superlattice layer 32a of the first conductivity type and the third superlattice layer 32c of the first conductivity type can be minimized.

In addition, light emitted from the active layer 50 is scattered by the third superlattice layer 32c of the first conductivity type, so that optical characteristics of the light emitting device can be improved.

In addition, the dot-shaped third superlattice layer 32c of the first conductivity type may be disposed lower than the first superlattice layer 32a of the first conductivity type in the form of a layer. Accordingly, the light scattering effect of the dot-shaped third superlattice layer 32c of the first conductivity type can be maximized to improve the luminous efficiency of the light emitting device.

Therefore, in the light emitting device according to the third embodiment, the first superlattice layer 32a of the first conductivity type and the third superlattice layer 32c of the first conductivity type are used for forming the first semiconductor layer 30 By controlling the crystallinity, the stress applied to the active layer 50 can be minimized. Accordingly, the recombination ratio of electrons and holes in the active layer 50 can be improved and the optical characteristics of the light emitting device can be improved.

In addition, light emitted from the active layer 50 is scattered by the third superlattice layer 32c of the first conductivity type arranged in a dot shape, so that light extraction efficiency of the light emitting device can be improved.

Therefore, in the light emitting device according to the third embodiment, the first superlattice layer 32a of the first conductivity type included in the first semiconductor layer 30 and the third superlattice layer 32c of the first conductivity type, The recombination rate of electrons and holes in the active layer 50 is improved to improve the optical characteristics of the light emitting device and the third superlattice layer of the first conductivity type in the form of a dot included in the first semiconductor layer 30 32c to scatter the light emitted from the active layer 50 to improve the light extraction efficiency.

5 is a graph illustrating the relationship between the internal quantum efficiency Quantum Efficiency, EQE).

Referring to FIG. 5, Ref in FIG. 5 is the internal quantum efficiency when the first superlattice layer of the first conductivity type according to the first embodiment is not formed in the n-type semiconductor layer.

As shown in FIG. 5, when the first super lattice layer of the first conductivity type according to the first embodiment is formed on the n-type semiconductor layer, the internal quantum efficiency is improved at both low current and high current. Thus, it can be seen that when the first superlattice layer of the first conductivity type according to the first embodiment is formed in the n-type semiconductor layer, the internal quantum efficiency of the light emitting device is improved at both the low current level and the high current level . Therefore, the light emitting device according to the embodiment can improve the optical characteristics at both low current and high current levels.

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.

A light emitting structure including a first semiconductor layer 30, an active layer 50, and a second semiconductor layer 70 may be formed on the substrate 10 or the unshown semiconductor layer 20.

The first semiconductor layer 30 may include the first conductive semiconductor layer 31 and the first superlattice layer 32a of the first conductivity type.

The first conductive semiconductor layer 31 may be formed of a compound semiconductor such as a Group 3-Group-5, Group-6, or the like, and may be doped with a first conductive dopant. For example, when the first conductive semiconductor layer 31 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 31 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 31 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 31 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. .

The first conductive semiconductor layer 31 may include a first superlattice layer 32a of a first conductivity type.

Hereinafter, the technical features of the light emitting device according to the embodiment will be described with reference to FIGS. 1 and 2. FIG.

1 and 2, in the light emitting device 100 according to the first embodiment, the first semiconductor layer 30 includes the first superlattice layer 32a of the first conductivity type, The crystallinity of the first semiconductor layer 30 can be controlled. Accordingly, the stress generated in the active layer 50 due to the difference in lattice constant between the first semiconductor layer 30 and the active layer 50 can be alleviated.

As described above, in the light emitting device 100 according to the first embodiment, the crystallinity of the first semiconductor layer 30 is controlled by the first superlattice layer 32a of the first conductivity type, And the recombination ratio of electrons and holes in the active layer 50 is improved, whereby the optical characteristics of the light emitting device can be improved.

Next, referring to FIG. 7, a second superlattice layer 40 may be formed on the first semiconductor layer 30.

The second superlattice layer 40 may have a lattice constant larger than that of the first semiconductor layer 30 and smaller than that of the active layer 50. Accordingly, the second superlattice layer 40 can effectively relax the strain due to the lattice mismatch between the first semiconductor layer 30 and the active layer 50.

Next, an active layer 50 may be formed on the second superlattice layer 40.

The active layer 50 is formed by electrons injected through the first semiconductor layer 30 and holes injected through the second semiconductor layer 70 formed thereafter to be determined by energy bands inherent in the active layer It is a layer that emits light with energy.

The active layer 50 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 50 may include a quantum well / quantum wall structure. For example, the active layer 50 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, an electron blocking layer 60 is formed on the active layer 50 to serve as electron blocking and cladding of the active layer 50, thereby improving the luminous efficiency.

For example, the electron blocking layer 60 may be formed of a semiconductor of Al _x In _y Ga _(1-xy) N (0? _{X ? 1, 0? Y ? 1} ) Lt; RTI ID = 0.0 &gt; 50 &lt; / RTI &gt;

The electron blocking layer 60 of the light emitting device 100 according to the embodiment can efficiently block the electrons that are ion-implanted into the p-type and overflow, thereby increasing the injection efficiency of holes.

Next, a second semiconductor layer 70 may be formed on the electron blocking layer 60.

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

For example, the second 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 semiconductor layer 70 is a p-type semiconductor layer, the second conductive dopant may include Mg, Zn, Ca, Sr, and Ba as a p-type dopant.

For example, the second semiconductor layer 70 may be formed of a second semiconductor layer 70 including a p-type impurity such as trimethyl gallium gas (TMGa), ammonia gas (NH 3), nitrogen gas (N 2), and magnesium The p-type GaN layer may be formed by implanting pentadienyl magnesium (EtCp ₂ Mg) {Mg (C ₂ H ₅ C ₅ H) ₂ }, but the present invention is not limited thereto.

In an embodiment, the first semiconductor layer 30 may be an n-type semiconductor layer, and the second semiconductor layer 70 may be a p-type semiconductor layer. Also, on the second semiconductor layer 70, a semiconductor, for example, 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 semiconductor layer 70.

In addition, the second electrode 82 may be formed on the exposed first semiconductor layer 30 as shown in FIG. 8 to manufacture the light emitting device according to the embodiment.

A plurality of light emitting devices according to embodiments may be arrayed on a substrate in the form of a package, and a light guide plate, a prism sheet, a diffusion sheet, a fluorescent sheet, or the like may be disposed on a path of light emitted from the light emitting device package.

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 semiconductor layer
32a: a first superlattice layer of a first conductivity type
40: second superlattice layer 50: active layer 60: electron blocking layer
70: second semiconductor layer 81: first electrode 82: second electrode

Claims (11)

A first semiconductor layer including a first conductive type semiconductor layer and a first superlattice layer of a first conductivity type having a composition of In _{x -} Ga _{1 - x} N / GaN (0 <x <1);
A second superlattice layer having a composition of In _y Ga _{1 - y} N / GaN (0 <y <1) on the first semiconductor layer;
An active layer on the second superlattice layer; And
And a second semiconductor layer on the active layer,
The first superlattice layer of the first conductivity type) is lower than the indium concentration of the second superlattice layer. The method according to claim 1,
Wherein the second superlattice layer of In _y Ga _{1 - y} N / GaN (0 <y <1) composition is not doped with the first conductive dopant. 3. The method of claim 2,
Wherein the first superlattice layer of the first conductivity type has an indium composition of 5% or less. The method of claim 3,
And the thickness of the first superlattice layer of the first conductivity type is 5 to 20 nm. The method of claim 3,
Wherein the first semiconductor layer has the first superlattice layer of the first conductivity type and the first conductivity type semiconductor layer alternately arranged. 3. The method of claim 2,
Wherein the indium concentration of the second superlattice layer of the In _y Ga _{1 - y} N / GaN (0 <y <1) composition is lower than the indium concentration of the active layer. The method according to claim 1,
Wherein the first superlattice layer of the first conductivity type includes either a dot shape or a layered shape. The method according to claim 1,
Wherein the first semiconductor layer further comprises a third superlattice layer of a first conductivity type having a composition of In _z Ga _{1 - z} N / GaN (0 < z < 1) in dot form. 9. The method of claim 8,
And the third superlattice layer of the first conductivity type has a diameter of 10 to 100 nm. 9. The method of claim 8,
And the third superlattice layer of the first conductivity type having a dot shape is disposed lower than the first superlattice layer of the first conductivity type. A lighting device comprising a light-emitting unit comprising the light-emitting element according to any one of claims 1 to 10.

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