KR102643093B1 - Semiconductor Device And Light Apparatus - Google Patents

Abstract

Embodiments relate to semiconductor devices and lighting devices.
The light emitting device according to the embodiment includes a first semiconductor layer including a first superlattice layer of a first conductivity type and a first conductivity type semiconductor layer of In _{x -} Ga _{1 - x} N/GaN (0 < x < 1) composition. And a second superlattice layer of a composition of In _y Ga _{1 - y} N/GaN (0<y<1) on the first conductive semiconductor layer, an active layer on the second superlattice layer, and a second superlattice layer on the active layer. It includes two semiconductor layers, 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 a light emitting device according to an embodiment, the first semiconductor layer may include a first superlattice layer of a first conductivity type. Accordingly, the crystallinity of the first semiconductor layer can be alleviated, thereby reducing stress caused by lattice mismatch between the first semiconductor layer and the active layer. Therefore, in the semiconductor device and lighting device according to the embodiment, the first semiconductor layer includes a first superlattice layer of the first conductivity type, thereby alleviating the stress occurring at the interface between the first semiconductor layer and the active layer, thereby reducing the intensity of the light emitting device. Luminous efficiency can be improved.

Description

Semiconductor Device And Light Apparatus}

The embodiment relates to a semiconductor device, and more specifically, to a semiconductor device and a lighting device.

Semiconductor devices containing compounds such as GaN and AlGaN have many advantages, such as having a wide and easily adjustable band gap energy, and can be used in a variety of ways, such as light emitting devices, light receiving devices, and various diodes.

In particular, light-emitting devices such as light emitting diodes and laser diodes using group 3-5 or group 2-6 compound semiconductor materials have been developed into red, green, and green colors through the development of thin film growth technology and device materials. Various colors such as blue and ultraviolet rays can be realized, and efficient white light can also be realized by using fluorescent materials or combining colors. Compared to existing light sources such as fluorescent lights and incandescent lights, it has low power consumption, semi-permanent lifespan, and fast response speed. , has the advantages of safety and environmental friendliness.

In addition, when light-receiving devices such as photodetectors or solar cells are manufactured using group 3-5 or group 2-6 compound semiconductor materials, the development of device materials absorbs light in various wavelength ranges to generate photocurrent. By doing so, light of various wavelengths, from gamma rays to radio wavelengths, can be used. In addition, it has the advantages of fast response speed, safety, environmental friendliness, and easy control of device materials, so it can be easily used in power control, ultra-high frequency circuits, or communication modules.

Therefore, semiconductor devices can replace the transmission module of optical communication means, the light emitting diode backlight that replaces the cold cathode fluorescence lamp (CCFL) that constitutes the backlight of LCD (Liquid Crystal Display) display devices, and fluorescent or incandescent light bulbs. Applications are expanding to include white light-emitting diode lighting devices, automobile headlights and traffic lights, and sensors that detect gas or fire. In addition, the applications of semiconductor devices can be expanded 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 this semiconductor light emitting device, electrons are supplied from the n-type semiconductor layer and holes are supplied from the p-type semiconductor layer, and light is generated when the electrons and holes recombine in the active layer.

At this time, stress may occur inside the active layer due to the difference in lattice constant between each semiconductor layer and the active layer, and the recombination probability of electrons and holes may decrease. Accordingly, the optical characteristics of the light emitting device deteriorate due to stress occurring inside the active layer, which may lead to problems with the light reliability of the light emitting device.

Embodiments are intended to provide a semiconductor device and a lighting device that can reduce stress occurring inside the active layer due to a difference in lattice constants between the semiconductor layer and the active layer.

The embodiment seeks to provide a semiconductor device and lighting device that can improve optical characteristics by reducing stress occurring inside the active layer.

The light emitting device according to the embodiment includes a first semiconductor layer including a first superlattice layer of a first conductivity type and a first conductivity type semiconductor layer of In _{x -} Ga _{1 - x} N/GaN (0 < x < 1) composition. and 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 a second semiconductor on the active 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 In _y Ga _{1 - y} N/GaN (0<y<1) may not be doped with the first conductive type dopant.

The indium composition of the first superlattice 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 superlattice 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 include a first superlattice layer of the first conductivity type and a semiconductor layer of the first conductivity type alternately disposed.

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).

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

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.

Embodiments may provide a semiconductor device and a lighting device that can relieve stress occurring inside the active layer.

Embodiments may provide a semiconductor device and a lighting device that can relieve stress occurring inside the active layer by controlling the crystallinity of the semiconductor layer.

Embodiments may provide a semiconductor device and lighting device that improve optical characteristics by alleviating stress occurring inside the active layer and increasing the probability of recombination of electrons and holes within the active layer.

1 is a cross-sectional view of a light-emitting device according to a first embodiment.
Figure 2 is a cross-sectional view of the first semiconductor layer of the light emitting device according to the first embodiment.
Figure 3 is a cross-sectional view of a light emitting device according to a second embodiment.
Figure 4 is a cross-sectional view of a light-emitting device according to a third embodiment.
Figure 5 is a diagram expressing the internal quantum efficiency of a light emitting device according to an embodiment as a graph.
6 to 8 are cross-sectional views showing the manufacturing process of a light-emitting device according to an embodiment.
Figure 9 is a cross-sectional view of a light emitting device package according to an embodiment.
Figure 10 is a perspective view of a lighting device according to an embodiment.

The present 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.

Even if matters described in a specific embodiment are not explained in other embodiments, they may be understood as descriptions related to other embodiments, as long as there is no explanation contrary to or contradictory to the matter in the other embodiments.

For example, if a feature for configuration A is described in a specific embodiment and a feature for configuration B is described in another embodiment, the description is contrary or contradictory even if an embodiment in which configuration A and configuration B are combined is not explicitly described. Unless otherwise stated, it should be understood as falling within the scope of the rights of the present invention.

Hereinafter, an embodiment that can specifically realize the above object will be described with reference to the attached drawings.

In the description of the embodiment according to the present invention, in the case where each element is described as being formed "on or under", (or under) includes both elements that are in direct contact with each other or one or more other elements that are formed (indirectly) between the two elements. Additionally, when expressed as "on or under," it can include not only the upward direction but also the downward direction based on one element.

The semiconductor device may include various electronic devices such as a light emitting device and a light receiving device, and both 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.

Light-emitting devices emit light when electrons and holes recombine, and the wavelength of this light is determined by the material's inherent energy band gap. Accordingly, the light emitted may vary depending on the composition of the material.

As shown in Figures 1 and 2, the light emitting device 100 according to the embodiment includes a substrate 10, an undoped semiconductor layer 20, a first conductive semiconductor layer 31, and In _{x -} Ga _{1 - A} first semiconductor layer 30, a second semiconductor layer 70, and an active layer 50 including first superlattice layers 32a and 32b of a first conductivity type of x N/GaN (0<x<1) composition ), a second superlattice layer 40 of In _y Ga _{1 - y} N/GaN (0<y<1) composition, an electron blocking layer 60, a first electrode 81, and a second It may include any one of the electrodes 82.

The substrate 10 may be made of a material with excellent thermal conductivity. The substrate 10 may be a conductive substrate or an insulating substrate. For example, the substrate 10 is sapphire (Al ₂ O ₃ ), SiC, Si, GaAs, GaN, ZnO, GaP, InP, Ge, Ga ₂ 0 ₃ At least one of these can be used. A concavo-convex structure may be formed on the substrate 10, but is not limited thereto.

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

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

Additionally, the first conductivity type semiconductor layer 31 may be implemented with a semiconductor compound, for example, at least one of a Group 3-5 compound semiconductor or a Group 2-6 compound semiconductor.

Additionally, the first conductive semiconductor layer 31 may be formed as a single layer or multiple layers. The first conductive semiconductor layer 31 may be doped with a first conductive type 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 Si, Ge, Sn, Se, and Te, but is not limited thereto. For example, the _{first conductive semiconductor} layer ₃₁ is _In It may include a semiconductor material with a composition formula of ≤1), but is not limited thereto. For example, the first conductive semiconductor layer 31 is formed of one or more of AlGaP, InGaP, AlInGaP, InP, GaN, InN, AlN, InGaN, AlGaN, InAlGaN, AlInN, AlGaAs, InGaAs, AlInGaAs, and GaP. It can be. For example, the indium composition of the first conductive semiconductor layer 31 may be 5% or less.

A 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. Additionally, 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 and the luminous efficiency of the light emitting device may be reduced. It may be possible, but it is not limited to this.

For example, the composition of the first superlattice layer 32a of the first conductivity type may be In _{x -} 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, if 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 may be affected, thereby reducing the luminous efficiency of the light emitting device. However, it is not limited to this.

Additionally, 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, without forming a separate layer like the second superlattice layer 40, the crystallinity of the first semiconductor layer 30 is increased by the first superlattice layer 32a of the first conductivity type. By controlling, the stress occurring in the active layer 50 and the first semiconductor layer 30 can be controlled.

Additionally, the first semiconductor layer 30 may include the first conductive semiconductor layer 31 and the first superlattice layer 32a of the first conductive type arranged in a pair. For example, when the first conductive semiconductor layer 31 and the first superlattice layer 32a of the first conductive type are arranged in pairs, the first conductive semiconductor layer 31 and the first superlattice layer 32a The first conductive superlattice layer 32a may be formed of 10 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 number of pairs of the first semiconductor layer 30 and the active layer 50 The stress generated in the active layer 50 may increase due to lattice mismatch, which may reduce the luminous efficiency of the light emitting device, but is not limited to this.

For example, when the number of the first conductive semiconductor layer 31 and the first superlattice layer 32a of the first conductive type exceeds 50 pairs, the crystallinity of the first semiconductor layer 30 is affected. The luminous efficiency of the light emitting device may decrease, but is not limited to this.

A light emitting device generates light by recombining 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 may change depending on the internal situation of the active layer.

In the prior art, an n-type semiconductor layer is formed and then an active layer and a p-type semiconductor layer are formed. However, stress may occur inside the active layer due to a difference in lattice constant between each semiconductor layer and the active layer. Therefore, the probability of recombination of electrons and holes in the active layer may be lowered due to stress occurring inside the active layer. Because of this, the luminous efficiency of the light emitting device may decrease. Accordingly, by forming a separate strain relaxation layer between the semiconductor layer and the active layer, stress generation due to lattice mismatch between the semiconductor layer and the active layer is minimized and the recombination probability of electrons and holes in the active layer is improved, thereby improving the luminous efficiency of the light emitting device. I was able to.

However, in the light emitting device according to the embodiment, the first superlattice layer 32a of the first conductivity type and the first conductivity type semiconductor layer 31 are formed inside the first semiconductor layer 30 rather than a separate strain relaxation layer. By controlling the crystallinity of the first semiconductor layer 30 by arranging them alternately, the stress caused by the lattice mismatch between the first semiconductor layer 30 and the active layer 50 is minimized and the luminous efficiency of the light emitting device is improved. It can be improved.

In addition, 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, thereby reducing the stress caused by the difference in lattice constants. 1 Can be absorbed in the semiconductor layer 30. Accordingly, stress occurring inside 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 stress due to the difference in lattice constant within the first semiconductor layer 30 is absorbed due to the first superlattice layer 32a of the first conductivity type. By doing so, the stress occurring inside the active layer 50 is reduced, thereby improving the recombination probability of electrons and holes inside the active layer 50, thereby improving the luminous efficiency of the light emitting device 100.

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

Additionally, the second superlattice layer 40 may not be doped with the first conductive dopant. Accordingly, the strain relaxation effect caused by the second superlattice layer 40 can only occur when a separate layer is formed.

The second superlattice layer 40 may have a lattice constant greater than that of the first semiconductor layer 30. The second superlattice layer 40 may have a lattice constant that is smaller than that of the active layer 50. The second superlattice layer 40 may have a lattice constant that is greater 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 that is 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 The strain applied to the active layer 50 can be alleviated by lattice mismatch.

The second superlattice layer 40 may have a lattice constant greater than that of the first superlattice layer 32a of the first conductivity type. The second superlattice layer 40 may have a lattice constant that is smaller than that of the active layer 50. The second superlattice layer 40 may have a lattice constant that is greater 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 lattice constant greater than that of the first superlattice layer 32a of the first conductivity type and a lattice constant smaller than that of the active layer 50, thereby forming the first conductivity type. The strain applied to the active layer 50 can be alleviated due to the lattice mismatch between the first superlattice layer 32a and the active layer 50.

Accordingly, the second superlattice layer 40 can effectively relieve strain caused by lattice mismatch between the first semiconductor layer 30 and the active layer 50.

The second superlattice layer 40 may have a structure 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. Additionally, the indium concentration of the second superlattice layer 40 may be higher than the indium concentration of the first semiconductor layer 30. Accordingly, the bandgap energy difference between the active layer 50 and the second superlattice layer 40 is smaller than the bandgap energy difference between the active layer 50 and the first semiconductor layer 30, so that the second superlattice The layer 40 can alleviate stress due to the bandgap energy difference, but is not limited to this.

For example, when the thickness of the second superlattice layer 40 is 50 to 300 nm and the indium composition is not 5 to 10%, the indium occurs in the active layer 50 by the second superlattice layer 40. The stress relieving effect may be reduced and the luminous efficiency of the light emitting device may be reduced.

An 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 can meet each other. The active layer 50 can emit light due to a difference in the band gap of the energy band according to the forming material of the active layer 50 when electrons and holes meet. The active layer 50 may emit at least one wavelength among ultraviolet rays, blue, green, and red.

The active layer 50 may optionally include a single quantum well, multiple quantum well (MQW), quantum wire structure, or quantum dot structure. The active layer 50 may be composed of a compound semiconductor. For example, the active layer 50 may be implemented with at least one of group 3-5 compound semiconductors or group 2-6 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, quantum well layers and quantum barrier layers may be alternately arranged. For example, the _quantum well layer and the _quantum barrier layer _{are each In} 1) It can be placed as a semiconductor material with the composition formula, or among GaInP/AlGaInP, GaP/AlGaP, InGaP/AlGaP, InGaN/GaN, InGaN/InGaN, GaN/AlGaN, InAlGaN/GaN, GaAs/AlGaAs, InGaAs/AlGaAs It may be formed in one or more pair structures, but is not limited thereto. The quantum well layer may be formed of a material with a lower band gap than 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 reduces the piezoelectric polarization effect between the active layer 50 and the second semiconductor layer 70, thereby reducing the hole injection efficiency from the second semiconductor layer 70 to the active layer 50. It 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 have a thickness of 20 nm to 100 nm. If the thickness of the electron blocking layer 60 is formed thinner than 20 nm, the piezoelectric polarization phenomenon of the second semiconductor layer 70 and the active layer 50 may not be alleviated. If the thickness of the electron blocking layer 60 is formed thicker than 100 nm, the injection efficiency of holes supplied from the second semiconductor layer 70 to the active layer 50 may decrease, but is not limited to this.

For example, the electron blocking layer 60 may have an InGaN/GaN structure. For example, when the electron blocking layer 60 has an InGaN/GaN structure, the indium composition 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 implemented with a semiconductor compound, for example, at least one of a Group 3-5 compound semiconductor or a Group 2-6 compound semiconductor. The second semiconductor layer 70 may be formed as a single layer or multilayer. The second semiconductor layer 70 may be doped with a second conductivity type dopant. For example, when the second semiconductor layer 70 is a p-type semiconductor layer, the second conductive dopant is a p-type dopant and may include Mg, Zn, Ca, Sr, Ba, etc.

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) It may include a semiconductor material having a composition formula, but 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, and GaP. there is.

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 portion 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 alloy containing 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 the metal or alloy and ITO (Indium-Tin-Oxide), IZO (Indium-Zinc-Oxide), IZTO (Indium-Zinc-Tin-Oxide), IAZO (Indium-Tin-Oxide). Transparent conductivity such as Aluminum-Zinc-Oxide), IGZO (Indium-Gallium-Zinc-Oxide), IGTO (Indium-Gallium-Tin-Oxide), AZO (Aluminum-Zinc-Oxide), ATO (Antimony-Tin-Oxide) 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 portion 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 portion of the first conductive 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 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 portion of the first conductive first 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 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 alloy containing at least one of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Cu, Au, and Hf. The second electrode 82 is formed of the metal or alloy and ITO (Indium-Tin-Oxide), IZO (Indium-Zinc-Oxide), IZTO (Indium-Zinc-Tin-Oxide), IAZO (Indium-Aluminum-Zinc-Oxide). A single layer or layer of transparent conductive materials such as Oxide), IGZO (Indium-Gallium-Zinc-Oxide), IGTO (Indium-Gallium-Tin-Oxide), AZO (Aluminum-Zinc-Oxide), and ATO (Antimony-Tin-Oxide). It can be multi-layered.

A light emitting device in the prior art forms an n-type semiconductor layer and then an active layer and a p-type semiconductor layer, and stress may occur inside the active layer due to a difference in lattice constant between each semiconductor layer and the active layer. Therefore, the probability of recombination of electrons and holes in the active layer may be lowered due to stress occurring inside the active layer. Because of this, the luminous efficiency of the light emitting device may decrease.

Accordingly, by forming a separate strain relaxation layer between the semiconductor layer and the active layer, stress generation due to lattice mismatch between the semiconductor layer and the active layer is minimized and the recombination probability of electrons and holes in the active layer is improved, thereby improving the luminous efficiency of the light emitting device. I was able to.

However, in the light emitting device according to the embodiment, the first superlattice layer 32a of the first conductivity type and the first conductive layer are formed inside the first semiconductor layer 30 rather than a separate strain relaxation layer between the semiconductor layer and the active layer. By arranging the semiconductor layers 31 alternately to control the crystallinity of the first semiconductor layer 30, stress caused by lattice mismatch between the first semiconductor layer 30 and the active layer 50 is minimized. The luminous efficiency of the light emitting device can be improved.

In the light emitting device 100 according to the first embodiment, the first semiconductor layer 30 controls the crystallinity of the first semiconductor layer 30 by including the first superlattice layer 32a of the first conductivity type. can do. Accordingly, stress occurring inside 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 can be absorbed by the first semiconductor layer 30, thereby reducing the stress occurring inside the active layer 50, thereby improving the recombination probability of electrons and holes inside the active layer 50, thereby producing light emission. The luminous efficiency of the device 100 can be improved.

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

3, the first semiconductor layer 30 of the light emitting device according to the second embodiment is any of the first conductive semiconductor layer 31 and the first superlattice layer 32b of the first conductive type. It can contain one.

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

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. Accordingly, the crystallinity of the first semiconductor layer 30 is controlled by the dot-shaped first conductive first superlattice layer 32b, thereby maintaining the lattice of the active layer 50 and the first semiconductor layer 30. By relieving stress occurring within the active layer 50 due to mismatch, the luminous efficiency of the light emitting device can be improved. In addition, the light emitted from the active layer 50 is scattered by the dot-shaped first conductive first superlattice layer 32b, so that the 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 arranged in a dot shape, the diameter size of the dots may be 10 to 100 nm. For example, when the diameter size of the dots of the first superlattice layer 32b of the first conductivity type is not 10 nm to 100 nm, the dot-shaped first superlattice layer 32b of the first conductivity type The light scattering effect may be reduced and the luminous efficiency of the light emitting device may be reduced, but it is not limited to this.

As shown in FIG. 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, so that In addition to alleviating the stress that occurs, the light emitted from the active layer 50 is scattered due to the first superlattice layer 32a of the first conductive type formed in the form of a dot, thereby improving the light extraction efficiency of the light emitting device 100. It can be improved.

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

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 the first conductive type, and a first conductive type semiconductor layer 31. It may include any one of the 1-conductivity type third superlattice layer 32c.

In the light emitting device according to the third embodiment of FIG. 4, the contents previously described in the light emitting device according to the first and second embodiments shown in FIGS. 1 and 2 can be adopted, and in the following, the main contents of the third embodiment are described. Let's describe the features.

As shown in FIG. 4, the first semiconductor layer 30 of the light emitting device according to the third embodiment has a dot shape with the first superlattice layer 32a of the first conductivity type. It may include 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, the light emitted from the active layer 50 is scattered by the third superlattice layer 32c of the first conductivity type, so that the optical characteristics of the light emitting device can be improved.

Additionally, the dot-shaped third superlattice layer 32c of the first conductivity type may be disposed lower than the layered first conductivity type first superlattice layer 32a. Accordingly, the light scattering effect of the dot-shaped third superlattice layer 32c of the first conductive 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 semiconductor layer 30 is formed by the first superlattice layer 32a of the first conductivity type and the third superlattice layer 32c of the first conductivity type. By controlling crystallinity, stress applied to the inside of the active layer 50 can be minimized. Accordingly, the optical characteristics of the light emitting device can be improved by improving the recombination rate of electrons and holes in the active layer 50.

In addition, the 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, thereby improving the light extraction 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 included in the first semiconductor layer 30 The optical characteristics of the light-emitting device are improved by increasing the recombination rate of electrons and holes in the active layer 50, and at the same time, the third superlattice layer of the first conductivity type in the form of a dot included in the first semiconductor layer 30 ( 32c) can simultaneously have the effect of improving light extraction efficiency by scattering the light emitted from the active layer 50.

Figure 5 is a graph showing the internal quantum efficiency (EQE) of a light emitting device according to an embodiment.

Referring to FIG. 5, in the graph of FIG. 5, Ref 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 superlattice layer of the first conductivity type according to the first embodiment is formed on the n-type semiconductor layer, it can be seen that the internal quantum efficiency is improved at both low and high currents. Accordingly, it can be seen that when the first superlattice layer of the first conductivity type according to the first embodiment is formed on the n-type semiconductor layer, the internal quantum efficiency of the light emitting device is improved at both low and high current levels. . Accordingly, the light emitting device according to the embodiment may have improved optical characteristics at both low and high current levels.

Next, Figures 6 to 8 are cross-sectional views showing the manufacturing process of a light-emitting device according to an embodiment.

First, the substrate 10 may be prepared as shown in FIG. 6. The substrate 10 may be made of a material with excellent thermal conductivity and may be a conductive substrate or an insulating substrate.

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

An undoped semiconductor layer 20 may be formed on the substrate 10. The undoped semiconductor layer 20 can alleviate lattice mismatch between the light emitting structure formed later and the substrate 10.

Thereafter, 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 undoped 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 conductive type.

The first conductive semiconductor layer 31 may be implemented with a semiconductor compound, for example, a group 3-5 group, group 2-6 compound semiconductor, and may be doped with a first conductive type dopant. For example, when the first conductive semiconductor layer 31 is an n-type semiconductor layer, the n-type dopant may include Si, Ge, Sn, Se, and Te, but is not limited thereto. _{The first conductive} semiconductor layer 31 has a composition _formula of _In It may include a semiconductor material having . For example, the first conductive semiconductor layer 31 is formed of one or more of GaN, InN, AlN, InGaN, AlGaN, InAlGaN, AlInN, AlGaAs, InGaAs, AlInGaAs, GaP, AlGaP, InGaP, AlInGaP, and InP. It can be.

The first conductive semiconductor layer 31 may be formed using a method such as chemical vapor deposition (CVD), molecular beam epitaxy (MBE), sputtering, or hydroxide vapor phase epitaxy (HVPE), but is not limited thereto. .

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

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

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, stress occurring inside 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, thereby forming the active layer 50. ) The stress occurring inside is reduced and the recombination rate of electrons and holes inside the active layer 50 is improved, thereby improving the optical characteristics of the light emitting device.

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

The second superlattice layer 40 may have a lattice constant that is greater 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 relieve strain caused by 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 meeting electrons injected through the first semiconductor layer 30 and holes injected through the second semiconductor layer 70, which is formed later, and is determined by the energy band inherent in the active layer (light-emitting layer) material. This 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 in a pair structure of one or more of InGaN/GaN, InGaN/InGaN, GaN/AlGaN, InAlGaN/GaN, GaAs/AlGaAs, InGaP/AlGaP, and GaP/AlGaP, but is limited thereto. It doesn't work.

Next, the electron blocking layer 60 is formed on the active layer 50 to serve as electron blocking and cladding (MQW cladding) of the active layer 50, thereby improving luminous efficiency.

For example, _the electron blocking layer 60 may be formed of _{an Al} It can have a higher band gap energy than the band gap energy of (50).

The electron blocking layer 60 of the light emitting device 100 according to the embodiment is p-type ion-injected to effectively block overflowing electrons and increase hole injection efficiency.

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 implemented as a compound semiconductor of group 3-5, group 2-6, etc., and may be doped with a second conductive type dopant.

For example, the second semiconductor layer 70 is a group 3-5 compound semiconductor doped with a second conductive dopant, such as 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 is a p-type dopant and may include Mg, Zn, Ca, Sr, Ba, etc.

For example, the second semiconductor layer 70 is a bicetyl cycle containing p-type impurities such as trimethyl gallium gas (TMGa), ammonia gas (NH3), nitrogen gas (N2), and magnesium (Mg) in the chamber. Pentadienyl magnesium (EtCp ₂ Mg) {Mg(C ₂ H ₅ C ₅ H) ₂ } may be implanted to form a p-type GaN layer, but the present invention is not limited thereto.

In an embodiment, the first semiconductor layer 30 may be implemented as an n-type semiconductor layer, and the second semiconductor layer 70 may be implemented as a p-type semiconductor layer, but are not limited thereto. Additionally, a semiconductor layer (not shown) having a polarity opposite to that of the second conductivity type, such as an n-type semiconductor layer, may be formed on the second semiconductor layer 70. Accordingly, the light emitting structure can be implemented as 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, the first electrode 81 can be formed on the second semiconductor layer 70.

Additionally, the light emitting device according to the embodiment can be manufactured by forming the second electrode 82 on the exposed first semiconductor layer 30 as shown in FIG. 8.

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

Next, Figure 9 is a cross-sectional view showing a light-emitting device package including a light-emitting device according to an 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, and the package body 1100. It may include a light-emitting element 100 disposed on (1100) and electrically connected to the first electrode 1200 and the second electrode 1300, and a molding member 1400 surrounding the light-emitting element 100. there is.

The package body 1100 may be made of silicone, synthetic resin, or metal. The package body 1100 may have an inclined surface formed on a side of the light emitting device.

The first electrode 1200 and the second electrode 1300 may be electrically separated from each other. The first electrode 1200 and the second electrode 1300 may serve to provide power to the light emitting device 100. The first electrode 1200 and the second electrode 1300 may serve to increase light efficiency by reflecting light generated from the light emitting device 100. 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 any one of a wire method, a flip chip method, or a die bonding method. In an embodiment according to the present invention, the light emitting device 100, the first electrode 1200, and the second electrode 1300 are each electrically connected through a wire, but the present invention is not limited thereto.

Additionally, the molding member 1400 may surround the light emitting device 100 and protect the light emitting device 100. The molding member 1400 may include a phosphor. The phosphor included in the molding member 1400 can change the wavelength of light emitted from the light emitting device 100.

The above-mentioned light emitting device is composed of a light emitting device package and can be used as a light source of a lighting system. For example, it can be used as a light source of a video display device or a lighting device.

Next, Figure 10 is an exploded perspective view of a lighting device according to an embodiment.

10, the lighting device according to the embodiment includes a cover 2100, a light source module 2200, a heat sink 2400, a power supply unit 2600, an internal case 2700, and a socket 2800. It can be included. Additionally, the lighting device according to the embodiment may further include one or more 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 an 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 sink 2400 and has guide grooves 2310 into which a plurality of light source units 2210 and a connector 2250 are inserted.

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

The power providing unit 2600 may include a protruding part 2610, a guide part 2630, a base 2650, and an extension part 2670. The inner case 2700 may include a molding portion along with the power supply portion 2600 therein. The molding part is a part where the molding liquid is solidified, and allows the power providing part 2600 to be fixed inside the inner case 2700.

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

Light-emitting devices include laser diodes in addition to the light-emitting diodes described above.

The laser diode, like the light emitting device, may include a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer having the above-described structure. In addition, the electro-luminescence phenomenon, in which light is emitted when a p-type first conductivity type semiconductor and an n-type second conductivity type semiconductor are bonded and an electric current flows, is used, but the directionality of the emitted light is different. There is a difference in phase. In other words, a laser diode can emit light with one specific wavelength (monochromatic beam) with the same phase and in the same direction by using a phenomenon called stimulated emission and constructive interference. Therefore, it can be used in optical communications, medical equipment, and semiconductor processing equipment.

An example of a light receiving element is a photodetector, which is a type of transducer that detects light and converts the intensity into an electrical signal. These photodetectors include photocells (silicon, selenium), photoconductive elements (cadmium sulfide, cadmium selenide), photodiodes (e.g., PDs with a peak wavelength in the visible blind spectral region or true blind spectral region), and phototransistors. , photomultiplier tubes, photoelectron tubes (vacuum, gas encapsulation), IR (Infra-Red) detectors, etc., but embodiments are not limited thereto.

Additionally, semiconductor devices such as photodetectors can generally be manufactured using direct bandgap semiconductors, which have excellent light conversion efficiency. Alternatively, photodetectors have various structures, and the most common structures include a pin-type photodetector using a p-n junction, a Schottky-type photodetector using a Schottky junction, and a MSM (Metal Semiconductor Metal) type photodetector. there is.

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

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

In addition, it can be used as a rectifier in electronic circuits through the rectification characteristics of a general diode using a p-n junction, and can be applied to ultra-high frequency circuits and oscillation circuits.

In addition, the above-described semiconductor device is not necessarily implemented only as a semiconductor and may further include a metal material in some cases. For example, a semiconductor device such as a light receiving device may be implemented using at least one of Ag, Al, Au, In, Ga, N, Zn, Se, P, or As, and may be implemented using a p-type or n-type dopant. It may also be implemented using doped semiconductor materials or intrinsic semiconductor materials.

Although the above description focuses on the examples, this is only an example and does not limit the present invention, and those skilled in the art will be able to You will see that various variations and applications are possible. For example, each component specifically shown in the examples can be modified and implemented. And these variations and differences in application should be construed as being included in the scope of the present invention as defined in the appended claims.

10: Substrate 20: Undoped semiconductor layer 30: First semiconductor layer
32a: First superlattice layer of 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 superlattice layer of a first conductivity type and a first conductivity type semiconductor layer of In _x- Ga _1-x N/GaN (0<x<1) composition;
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
Comprising a second semiconductor layer on the active layer,
The indium concentration of the first superlattice layer of the first conductivity type is lower than the indium concentration of the second superlattice layer,
A light emitting device wherein the indium concentration of the second superlattice layer is lower than the indium concentration of the active layer. According to paragraph 1,
The second superlattice layer of the In _y Ga _{1 - y} N/GaN (0<y<1) composition is a light emitting device that is not doped with a first conductive type dopant. According to paragraph 2,
A light emitting device wherein the indium composition of the first superlattice layer of the first conductivity type is 5% or less. According to paragraph 3,
A light emitting device wherein the first superlattice layer of the first conductivity type has a thickness of 5 to 20 nm. According to paragraph 3,
The first semiconductor layer is a light emitting device in which a first superlattice layer of the first conductivity type and a semiconductor layer of the first conductivity type are alternately disposed. delete According to paragraph 1,
A light emitting device wherein the first superlattice layer of the first conductivity type includes either a dot form or a layer form. According to paragraph 1,
The first semiconductor layer is a light emitting device further comprising a first conductive third superlattice layer having a dot-shaped In _z Ga _{1 - z} N/GaN (0 < z < 1) composition. According to clause 8,
A light emitting device wherein the diameter size of the dot shape of the third superlattice layer of the first conductivity type is 10 to 100 nm. According to clause 8,
A light emitting device wherein 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 including the light-emitting element of any one of claims 1 to 5 and 7 to 10.

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