KR101289442B1 - Nitride based light emitting diode comprising distributed bragg reflector and manufacturing method thereof - Google Patents

Abstract

PURPOSE: A nitride semiconductor light emitting diode which includes a distributed bragg reflector and manufacturing method thereof is provided to improve reflectivity by adjusting a thickness of a reflecting layer. CONSTITUTION: Multiple reflecting layers are laminated on the backside of a substrate. A Distributed Bragg Reflector is formed by laminating the reflecting layers. The Distributed Bragg Reflector comprises a first reflecting body (110) and a second reflecting body (120). The first reflecting layer (111) and the second reflecting layer (112) includes oxide material which has different refractive index with each other. A first and a second reflecting body are formed by laminating the first and the second reflecting layer.

Description

Nitride semiconductor light emitting device comprising a distributed Bragg reflector and a method of manufacturing the same {Nitride based Light Emitting Diode comprising Distributed Bragg Reflector and manufacturing method}

The present invention forms a distributed Bragg reflector consisting of reflectors having different thicknesses of the average reflecting layer on the lower surface of the substrate to ensure high reflectance of light in a wide wavelength range, nitride that can exhibit a high color rendering index and excellent luminous efficiency A semiconductor light emitting device and a method of manufacturing the same.

Conventional nitride semiconductor devices include, for example, GaN-based nitride semiconductor devices, which include high-speed switching and high-output devices such as blue or green LED light emitting devices, MESFETs and HEMTs, and the like in GaN-based nitride semiconductor light emitting devices. It is applied to the back.

In particular, blue or green LED light-emitting devices have already been mass-produced, and global sales are increasing.

As shown in FIG. 1, the basic structure of the conventional GaN semiconductor light emitting device is a reflective metal layer 10 formed on the lower surface of the sapphire substrate 11 and an n-type nitride semiconductor layer formed on the upper surface of the sapphire substrate 11. (12), the active layer 13, the p-type nitride semiconductor layer 14, the p-side electrode 15, and the n-side electrode 16 formed in the exposed region of the n-type nitride semiconductor layer 12.

In the conventional GaN semiconductor light emitting device, the sapphire substrate 11 is mainly used as a growth substrate, and the reflective metal layer 10 is used to reflect the light traveling downward from the active layer 13 upward.

However, when the reflective metal layer 10 is formed on the lower surface of the sapphire substrate 11 by using a metal having high reflectance such as aluminum, the reflective metal layer 10 may be laser scribed during the manufacturing process of the light emitting device. Since the metal of the reflective metal layer 10 is opaque during the process, it is difficult to align the scribing direction, making it difficult to perform the laser scribing process for the sapphire substrate 11.

Meanwhile, efforts have been made to improve light extraction efficiency by using a distributed Bragg reflector (DBR) instead of the reflective metal layer, and TiO ₂ / SiO ₂ is used instead of the reflective metal layer on the lower surface of the sapphire substrate 11. It may be repeated periodically to form a distributed Bragg reflector. However, in this case, the reflectance is drastically reduced for wavelengths above about 500 nm. Therefore, when the LED chip to which the distributed Bragg reflector is applied is mounted in the LED package that realizes the white light, the LED chip exhibits high reflectance for light in the blue wavelength region emitted from the LED chip, but does not apply to light in the green or red wavelength region. There is a problem that the distributed Bragg reflector does not exhibit effective reflection properties.

Korean Patent No. 721147 discloses forming a distributed Bragg reflector as a current blocking layer, but the Distributed Bragg reflector may also exhibit an excellent reflection effect only for a wavelength of a predetermined region.

Therefore, there is a continuing need for the development of a light emitting device capable of exhibiting excellent reflectance in a wider wavelength range.

Accordingly, the present inventors have researched and tried to develop a nitride semiconductor light emitting device including a distributed Bragg reflector exhibiting excellent reflectance in a broad wavelength range, and thus forming a distributed Bragg reflector formed by stacking a plurality of reflective layers below the substrate. The present invention has been completed by discovering that the reflectivity of the light having a wide wavelength range can be realized by adjusting the thickness of the reflective layer.

 Disclosure of Invention An object of the present invention is to provide a nitride semiconductor light emitting device having improved reflectance of light in a wide wavelength band and a white light emitting device including the same.

Another object of the present invention is to provide a manufacturing method which can easily manufacture the nitride semiconductor light emitting device.

The nitride semiconductor light emitting device of the present invention for achieving the above object is a substrate, n-type nitride layer; Active layer; a p-type nitride layer and a distributed Bragg reflector formed by stacking a plurality of reflective layers below the substrate, wherein the distributed Bragg reflector includes a first reflecting portion and a second reflecting portion from below, each reflecting portion The first reflection layer and the second reflection layer, each of which includes oxide materials having different refractive indices, are alternately stacked to form an average thickness M1 of the reflective layer constituting the first reflection portion and the average thickness M2 of the reflective layer constituting the second reflection portion. ) Are different from each other.

In addition, the nitride semiconductor light emitting device of the present invention includes a substrate, an n-type nitride layer; Active layer; a p-type nitride layer and a distributed Bragg reflector formed by stacking a plurality of reflective layers below the substrate, wherein the distributed Bragg reflector includes a first reflecting portion, a second reflecting portion, and a third reflecting portion from below; However, each reflecting portion is formed by alternately stacking first and second reflecting layers including oxide materials having different refractive indices, and forming an average thickness M1 of the reflecting layer forming the first reflecting portion and a reflecting layer forming the second reflecting portion. The average thickness M2 and the average thickness M3 of the reflective layer constituting the third reflecting portion are different from each other.

In another aspect, the present invention is characterized by a white light emitting device including a light emitting element for emitting light of a wavelength different from the light emitted from the nitride light emitting device and a light emitting device package comprising the same.

The method of manufacturing the nitride light emitting device may include forming a distributed Bragg reflector by stacking a plurality of reflective layers on a lower surface of a substrate; And forming an n-type nitride layer, an active layer, and a p-type nitride layer on an upper surface of the substrate, and forming a first reflecting portion and a second reflecting portion from below in forming the distributed Bragg reflector. The reflective part is formed by alternately stacking the first and second reflective layers made of oxide materials having different refractive indices, and the average thickness M1 of the reflective layer constituting the first reflective portion and the average thickness M2 of the reflective layer constituting the second reflective portion (M2). To form differently).

The method of manufacturing the nitride light emitting device may include forming a distributed Bragg reflector by stacking a plurality of reflective layers on a lower surface of a substrate; And forming an n-type nitride layer, an active layer, and a p-type nitride layer on an upper surface of the substrate, wherein the first reflecting portion, the second reflecting portion, and the third reflecting portion from below are formed in the forming of the distribution Bragg reflector. Forming a portion, and each reflecting portion is formed by alternately stacking a first reflection layer and a second reflection layer made of oxide materials having different refractive indices, and have an average thickness M1 of the reflection layer constituting the first reflection portion and a reflection layer constituting the second reflection portion. And forming an average thickness M2 of the reflective layer and the average thickness M3 of the reflective layer forming the third reflecting portion different from each other.

The nitride semiconductor light emitting device of the present invention can improve the luminous efficiency by totally reflecting light directed toward the lower direction of the sapphire substrate by the plurality of reflective layers having different refractive indices in the upper direction.

In particular, it is possible to ensure high reflectance not only for blue light in the wavelength range of 400 to 500 nm but also for light in the wavelength range of 500 to 700 nm, and includes a light emitting element that emits light having a wavelength other than blue light. In case of construction, excellent color rendering index can be obtained.

1 is a cross-sectional view of a conventional nitride semiconductor light emitting device.
2 is a cross-sectional view showing a cross section of a nitride semiconductor light emitting device according to an embodiment of the present invention.
3 shows an enlarged configuration of a distributed Bragg reflector 100 according to an embodiment of the nitride semiconductor light emitting device.
4 shows an enlarged configuration of a distribution Bragg reflector 100 of another embodiment of the nitride semiconductor light emitting device.
5 is a graph confirming reflectance characteristics of the distributed Bragg reflector of the embodiment.
6 is a graph confirming reflectance characteristics of the distributed Bragg reflector of the comparative example.

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described in detail below. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

Hereinafter, a nitride based light emitting device according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Nitride-based light emitting device

2 is a cross-sectional view of a horizontal nitride semiconductor light emitting device according to a first embodiment of the present invention.

As shown in FIG. 2, the nitride semiconductor light emitting device according to the exemplary embodiment of the present invention has a distributed Bragg reflector 100 and a sapphire substrate 140 having a plurality of reflective layers stacked on a lower surface of the sapphire substrate 140. The buffer layer 150, the n-type nitride layer 160, the active layer 170, the p-type nitride layer 180, the transparent electrode layer 190, the p-side electrode 191 and the n-side electrode 192 are disposed in an upper direction thereof. Include.

3 is an enlarged view of the distribution Bragg reflector 100 of the horizontal nitride semiconductor light emitting device.

The distributed Bragg reflector 100 includes a first reflecting unit 110 and a second reflecting unit 120 from below, and each reflecting unit alternately includes a first reflecting layer and a second reflecting layer made of oxide materials having different refractive indices. It is laminated repeatedly. In addition, the average thickness M1 of the reflective layer constituting the first reflecting unit 110 and the average thickness M2 of the reflective layer constituting the second reflecting unit 120 are different from each other, preferably M1 <M2.

The first reflector 110 is included to reflect light having a wavelength of 400 to 500 nm, and the second reflector 120 is included to reflect light having a wavelength of 500 to 700 nm.

4 is an enlarged view of another distributed Bragg reflector 100 of the horizontal nitride semiconductor light emitting device.

The distributed Bragg reflector 100 includes a first reflecting unit 110, a second reflecting unit 120, and a third reflecting unit 130 from below, and each reflecting unit is formed of an oxide material having different refractive indices. The reflective layer and the second reflective layer are alternately stacked. In addition, the average thickness M1 of the reflective layer constituting the first reflecting unit 110, the average thickness M2 of the reflective layer constituting the second reflecting unit 120, and the average thickness M3 of the reflective layer constituting the third reflecting unit 130. ) Are different from each other, preferably M1 <M2 <M3. That is, the average thickness of the reflective layer constituting the first reflecting portion 110 at the bottom is the smallest, and the average thickness of the reflective layer constituting the third reflecting portion 130 adjacent to the bottom of the substrate is the largest.

The first reflector 110 is included to reflect light having a wavelength of 400 to 500 nm, the second reflector 120 is included to reflect light having a wavelength of 500 to 600 nm, and the third reflector ( 130 is included for the reflection of light having a wavelength of 600-700 nm.

Each of the reflectors may be formed by alternately stacking a first reflection layer and a second reflection layer made of oxide materials having different refractive indices, and the first reflection layer is made of a material having a refractive index of 1.2 to 1.5, and the second reflection layer May be made of a material having a refractive index of 2.0 to 3.0. More specifically, the first reflection layer is made of SiO _X (1 ≦ _X ≦ 3) or MgF ₂ , and the second reflection layer is made of TiO _x (1 ≦ _X ≦ 3) or ZrO ₂ , most preferably. The first reflection layer is formed of SiO ₂ , the second reflection layer is preferably formed of TiO ₂ . That is, for example, the first reflection layer 111 to the fourth reflection layer 114 is a laminated structure in which SiO ₂ and TiO ₂ are alternately repeated, and the first reflection layer 111 is formed of SiO ₂ , and the second reflection layer ( 112 is formed of TiO ₂ , and the third reflection layer 113 is formed of SiO ₂ in the same manner as the first reflection layer 111, and the fourth reflection layer 114 is formed of TiO ₂ in the same manner as the second reflection layer 112. Can be formed.

In this case, the first reflection layer constituting the first reflection portion 110 has a thickness of 50 to 90 nm, preferably 55 to 85 nm, and the first reflection layer constituting the second reflection portion 120 is 80 to 110 nm. Preferably, represent a thickness of 85 ~ 105 nm, forming a third reflecting portion 130 The first reflective layer has a thickness of 90 to 135 nm, preferably 95 to 120 nm. In addition, the second reflection layer constituting the first reflection portion 110 has a thickness of 30 to 60 nm, preferably 35 to 55 nm, the second reflection layer constituting the second reflection portion 120 is 50 to 80 nm, Preferably, the thickness is 55 to 75 nm, and the second reflection layer constituting the third reflection portion 130 is 60 to 90 nm, preferably 65 to 85 nm.

And forming the first reflecting unit (110) The average thickness of the first reflective layer is 55 to 85 nm, the average thickness of the first reflective layer constituting the second reflective portion 120 is 85 to 105 nm, and the average thickness of the first reflective layer constituting the third reflective portion 130. Is preferably 95 to 115 nm. In addition, the average thickness of the second reflective layer constituting the first reflective portion 110 is 35 to 55 nm, the average thickness of the second reflective layer constituting the second reflective portion 120 is 55 to 75 nm, the third reflective portion It is preferable that the average thickness of the 2nd reflective layer which comprises 130 is 65-85 nm.

In addition, it is preferable that the uppermost reflective layer formed under the substrate 140 and in contact with the substrate among the reflective layers is made of TiO _x (1 ≦ _X ≦ 3). In general, the larger the difference in refractive index between the materials of each layer in the plurality of layers, the higher the reflectance. The uppermost reflective layer in contact with the substrate is formed by sapphire used for the substrate and TiO _x (1 ≦ _X ≦ 3) having a large refractive index difference. It is advantageous to.

Meanwhile, the distributed Bragg reflector 100 including the first reflecting unit 110, the second reflecting unit 120, and the third reflecting unit 130 preferably includes a total of 20 to 80 reflective layers, more preferably. Preferably 30 to 50 layers. When the distribution Bragg reflector 100 is composed of layers below the above range, it exhibits a reflection effect only for light in some wavelength bands, and thus it is impossible to secure sufficient reflectance in a wide wavelength band. It takes a long time to manufacture and difficult source management, so it is difficult to implement an economic process.

The distribution Bragg reflector 100 of the present invention may totally reflect the light directed toward the lower direction of the sapphire substrate 140 in the upper direction. In addition, the thickness of each reflecting layer tends to decrease as the distribution Bragg reflector approaches the substrate from the bottom as a whole, and when reflecting the thickness condition of each reflecting layer as described above, the reflectance for light in a wide range of wavelengths is increased. , Reflectance of more than 90% for light of 400 ~ 700 nm wavelength.

In addition to the sapphire, the substrate 140 may be formed of a compound such as SiC, Si, GaN, ZnO, GaAs, GaP, LiAl ₂ O ₃ , BN, or AlN. In addition, the buffer layer 150 may be selectively formed to solve the lattice mismatch between the substrate 140 and the n-type nitride layer 160, for example, may be formed of AlN or GaN.

The n-type nitride layer 160 is formed on the upper surface of the substrate 140 or the buffer layer 150 and is formed of nitride to which the n-type dopant is doped. The n-type dopant may be silicon (Si), germanium (Ge), tin (Sn), or the like. Here, the n-type nitride layer 160 is a stacked structure in which a first layer made of n-type AlGaN or undoped AlGaN doped with Si and a second layer made of n-type GaN doped with undoped or Si are formed. Can be. Of course, the n-type nitride layer 130 may be grown as a single n-type nitride layer, but may be formed as a laminated structure of the first layer and the second layer to act as a carrier limiting layer having good crystallinity without cracks. .

The active layer 170 may be formed of a single quantum well structure or a multi-quantum well structure between the n-type nitride layer 160 and the p-type nitride layer 180, and electrons flowing through the n-type nitride layer 160 and p As holes flowing through the nitride layer 180 are re-combined, light is generated. Here, the active layer 170 is a multi-quantum well structure, wherein the quantum barrier layer and the quantum well layer are each Al _x Ga _y In _z N (where x + y + z = 1, 0 ≦ x ≦ 1, 0 ≦ y ≤ 1, 0 ≤ z ≤ 1). The active layer 170 having a structure in which the quantum barrier layer and the quantum well layer are repeatedly formed may suppress spontaneous polarization due to stress and deformation generated.

The p-type nitride layer 180 is formed by alternately stacking a first layer made of, for example, p-type AlGaN or undoped AlGaN doped with Mg, and a second layer made of p-type GaN doped with undoped or Mg. Can be. In addition, the p-type nitride layer 180 may be grown as a single-layer p-type nitride layer similarly to the n-type nitride layer 160, but may be formed in a laminated structure to act as a carrier limiting layer having good crystallinity without cracks. have.

The transparent electrode layer 190 is a layer provided on the upper surface of the p-type nitride layer 180, the transparent electrode layer 190 is made of a transparent conductive oxide, the material of In, Sn, Al, Zn, Ga, etc. Element, and may be formed of any one of, for example, ITO, CIO, ZnO, NiO, and In ₂ O ₃ .

White light emitting device

Since the blue light having a wavelength of about 450 nm is emitted from the active layer of the nitride light emitting device, the white light emitting device of the present invention may further include a light emitting element emitting light having a wavelength different from that emitted from the nitride light emitting device. .

The light emitting element may be a YAG series as a yellow phosphor, and a preferable example of the YAG series yellow phosphor is a chemical formula (Y _{1 - x} Gd _x ) ₃ (Al _{1 - y} Ga _y ) ₅ O ₁₂ : Ce a ^{3 +} (where 0 ≤ x ≤ 1, 0 ≤ y ≤ 1 Im) fluorescent material represented by like.

In particular, since the white light emitting device has a color rendering index (CRI) of 85 or more, the light emitted from the light emitting device can be reproduced closer to the reference light than the conventional light emitting device.

In addition, the present invention may be implemented as a light emitting device package including the white light emitting device, which may be applied to a lighting device.

Manufacturing method of nitride based light emitting device

Hereinafter, a method of manufacturing a nitride semiconductor light emitting device according to an embodiment of the present invention will be described below.

In the method of manufacturing a nitride semiconductor light emitting device according to an embodiment of the present invention, first, a plurality of reflective layers are stacked on one surface of a sapphire substrate 140 to form a distributed Bragg reflector 100.

At this time, the distribution Bragg reflector 100 is the second reflecting portion 120 and the first reflecting portion 110 in order from the substrate, or the third reflecting portion 130, the second reflecting portion 120 and the first The reflector 110 may be formed in order.

Each reflector is formed by alternately stacking first and second reflection layers made of oxide materials having different refractive indices, and the first reflection layer is made of a material having a refractive index of 1.2 to 1.5, and the second reflection layer is It may be made of a material having a refractive index of 2.0 ~ 3.0. More specifically, the first reflection layer is made of SiO _X (1 ≦ _X ≦ 3) or MgF ₂ , and the second reflection layer is made of TiO _x (1 ≦ _X ≦ 3) or ZrO ₂ , most preferably. The first reflection layer is formed of SiO ₂ , the second reflection layer is preferably formed of TiO ₂ .

The first reflection layer and the second reflection layer may be formed by a plasma enhanced chemical vapor deposition (PECVD) method, a sputtering method, a MOCVD method, or an electron beam evaporation method. For example, SiO ₂ The first reflective layer 111 may be formed by reactive sputtering using Ar as a carrier gas and Si target and O ₂ , and the TiO ₂ second reflective layer may include Ar as a carrier gas and a Ti target and O. It can be formed by a reactive sputtering method using ₂ .

The average thickness M1 of the reflective layer constituting the first reflecting portion 110 and the average thickness M2 of the reflective layer constituting the second reflecting portion 120 are respectively stacked so as to be different from each other, preferably M1 <M2. Lay so that.

In addition, when the first reflector 110, the second reflector 120, and the third reflector 130 are included, the average thickness M1 and the second reflector of the reflective layer constituting the first reflector 110 are described. The average thickness M2 of the reflective layer constituting the 120 and the average thickness M3 of the reflective layer constituting the third reflecting unit 130 are respectively stacked so as to be different from each other, and preferably, M1 <M2 <M3. do. That is, the average thickness of the reflective layer constituting the third reflective portion 130 stacked first adjacent to the substrate is the largest, and the average thickness of the reflective layer constituting the first reflective portion 110 stacked last is the smallest.

More specifically, the first reflecting layer constituting the first reflecting portion 110 has a thickness of 50 to 90 nm, preferably 55 to 85 nm, and forms the second reflecting portion 120. The first reflective layer has a thickness of 80 to 110 nm, preferably 85 to 105 nm, and the first reflective layer constituting the third reflective portion 130 has a thickness of 90 to 135 nm, preferably 95 to 120 nm. Lay so that. In addition, the second reflection layer constituting the first reflection portion 110 has a thickness of 30 to 60 nm, preferably 35 to 55 nm, the second reflection layer constituting the second reflection portion 120 is 50 to 80 nm, Preferably, the thickness is 55 to 75 nm, and the second reflection layer constituting the third reflection portion 130 is laminated to have a thickness of 60 to 90 nm, preferably 65 to 85 nm.

In addition, it is preferable that the uppermost reflective layer formed under the substrate 140 and in contact with the substrate among the reflective layers is made of TiO _x (1 ≦ _X ≦ 3). In general, the larger the difference in refractive index between the materials of each layer in the plurality of layers, the higher the reflectance. The uppermost reflective layer in contact with the substrate is formed by sapphire used for the substrate and TiO _x (1 ≦ _X ≦ 3) having a large refractive index difference. It is advantageous to.

After the distribution Bragg reflector is formed as described above, the sapphire substrate 140 is inverted up and down, so that the buffer layer 150 and the n-type nitride layer 160 are formed on the other surface of the sapphire substrate 140, that is, the upper surface of the sapphire substrate 140. The active layer 170 and the p-type nitride layer 180 are sequentially formed.

The buffer layer 150 may be selectively formed on an upper surface of the substrate 140 to eliminate lattice mismatch between the substrate 140 and the n-type nitride layer 160. Here, the buffer layer 150 may be formed using, for example, AlN or GaN.

The n-type nitride layer 160 may be formed of an n-GaN layer. For example, the n-type nitride layer 160 may be formed by supplying a silane gas containing an n-type dopant such as NH ₃ , trimetalgallium (TMG), and Si, thereby converting the n-GaN layer into an n-type nitride layer. Can grow.

Next, the active layer 170 may be provided as a single quantum well structure or a multi quantum well structure in which a plurality of quantum well layers and a quantum barrier layer are alternately stacked. Here, the active layer 170 is made of a multi-quantum well structure, the quantum barrier layer and the quantum well layer is Al _x Ga _y In _z N (where x + y + z = 1, 0≤x≤1, 0 ≤ y ≤ 1, 0 ≤ z ≤ 1).

For example, the p-type nitride layer 180 may be formed by alternately stacking a first layer of p-type AlGaN doped with Mg and a second layer of p-type GaN doped with Mg. In addition, the p-type nitride layer 180 can be grown into a single p-type nitride layer similarly to the n-type nitride layer 160.

The transparent electrode layer 190 is formed on the upper surface of the p-type nitride layer 180. The transparent electrode layer 190 is made of a transparent conductive oxide, the material is In, Sn,

It includes an element such as Al, Zn, Ga, and may be formed of any one of, for example, ITO, CIO, ZnO, NiO, In2O3.

After forming the transparent electrode layer 190 as described above, one region of the n-type nitride layer 160 may be exposed by lithography etching from the transparent electrode layer 190 to one region of the n-type nitride layer 160. .

When one region of the n-type nitride layer 160 is exposed, the n-side electrode 192 may be formed in one region of the n-type nitride layer 160 exposed. The p-side electrode 191 may be formed on the upper surface of the transparent electrode layer 190.

Hereinafter, the nitride semiconductor light emitting device of the present invention will be described in more detail with reference to the following examples.

Example  One

In order to form a nitride-based light emitting device as shown in FIG. _2, a distributed Bragg reflector 100 was formed by alternately stacking SiO ₂ and TiO ₂ layers on a sapphire substrate as shown in Table 1 below.

Reflector Reflective layer Thickness (nm) Average thickness of the reflecting layer (nm) SiO ₂ TiO ₂ all First Reflector

SiO ₂ 56.0 62.4 47.4 54.9 TiO ₂ 37.0 SiO ₂ 58.0 TiO ₂ 47.0 SiO ₂ 62.0 TiO ₂ 48.0 SiO ₂ 64.0 TiO ₂ 50.0 SiO ₂ 72.0 TiO ₂ 55.0 Second reflector
SiO ₂ 95.0 94.2 70.2 82.2 TiO ₂ 55.0 SiO ₂ 84.0 TiO ₂ 67.0 SiO ₂ 88.0 TiO ₂ 76.0 SiO ₂ 107.0 TiO ₂ 76.0 SiO ₂ 97.0 TiO ₂ 77.0 Board Sapphire

In addition, GaN was applied as a nitride layer of the nitride light emitting device, and the transparent conductive layer was formed of indium tin oxide (ITO) to obtain a light emitting device as shown in FIG. 2.

Next, a yellow phosphor was coated on the light emitting device to form a white light emitting device.

Example  2

In order to form a nitride-based light emitting device as shown in FIG. 2, a distributed Bragg reflector 100 was formed by alternately stacking SiO ₂ and TiO ₂ layers on a sapphire substrate as shown in Table 2 below.

Reflector Reflective layer Thickness (nm) Average thickness of the reflecting layer (nm) SiO ₂ TiO ₂ all First Reflector

SiO ₂ 56.0 62.6 48.3 55.5 TiO ₂ 37.0 SiO ₂ 58.0 TiO ₂ 47.0 SiO ₂ 62.0 TiO ₂ 48.0 SiO ₂ 56.0 TiO ₂ 44.0 SiO ₂ 56.0 TiO ₂ 44.0 SiO ₂ 70.0 TiO ₂ 55.0 SiO ₂ 64.0 TiO ₂ 50.0 SiO ₂ 69.0 TiO ₂ 55.0 SiO ₂ 72.0 TiO ₂ 55.0 Second reflector SiO ₂ 95.0 86.0 64.0 75.0 TiO ₂ 55.0 SiO ₂ 81.0 TiO ₂ 51.0 SiO ₂ 84.0 TiO ₂ 67.0 SiO ₂ 81.0 TiO ₂ 62.0 SiO ₂ 87.0 TiO ₂ 73.0 SiO ₂ 88.0 TiO ₂ 76.0 Third Reflector SiO ₂ 105.0 100.0 70.6 85.3 TiO ₂ 65.0 SiO ₂ 96.0 TiO ₂ 65.0 SiO ₂ 95.0 TiO ₂ 70.0 SiO ₂ 107.0 TiO ₂ 76.0 SiO ₂ 97.0 TiO ₂ 77.0 Board Sapphire

In addition, GaN was applied as a nitride layer of the nitride light emitting device, and the transparent conductive layer was formed of indium tin oxide (ITO) to obtain a light emitting device as shown in FIG. 2.

Next, a yellow phosphor was coated on the light emitting device to form a white light emitting device.

Comparative example

Except for forming a distributed Bragg reflector by stacking a total of 22 layers (11 pairs) by alternately repeating a SiO ₂ layer and a TiO ₂ layer on a sapphire substrate with a uniform thickness of 77.2 nm and 45.6 nm, respectively. After the light emitting device was manufactured in the same manner, a phosphor was coated to form a white light emitting device.

Reflectances of the distributed Bragg reflectors were measured in the light emitting devices of Examples and Comparative Examples, which are shown in FIGS. 5 and 6, respectively.

As shown in FIG. 5, it was confirmed that the distributed Bragg reflector of Example 2 exhibited a reflectance of 90% or more with respect to light in the wavelength band of 400 to 700 nm. However, as shown in FIG. 6, the distribution Bragg reflector of the comparative example exhibited excellent reflectance only for light in the blue wavelength region of about 400 to 500 nm, and thus it was confirmed that the reflecting effect was exhibited in the narrow wavelength band.

And the color rendering index was measured from the difference with the eight kinds of test colors determined according to DIN6169 from the reference light source, and the results are shown in Table 3 below.

Example 1 Example 2 Comparative example Color rendering index 86 87 81

As shown in Table 3, the light emitting device of the embodiment shows a higher color rendering index than the comparative example, it was confirmed that the color reproduction (color rendering properties) of the object illuminated by the light emitted in the embodiment.

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 embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. . Accordingly, the true scope of the present invention should be determined by the following claims.

100: distribution Bragg reflector 110: first reflecting portion
111: first reflective layer 112: second reflective layer
113: third reflective layer 114: fourth reflective layer
120: second reflecting unit 130: third reflecting unit
140: substrate 150: buffer layer
160: n-type nitride layer 170: active layer
180: p-type nitride layer 190: transparent electrode layer
191: p-side electrode 192: n-side electrode

Claims (30)

Substrate, n-type nitride layer, active layer, p-type nitride layer and
A distributed Bragg reflector formed by stacking a plurality of reflective layers below the substrate;
The distribution Bragg reflector includes a first reflecting portion and a second reflecting portion from below,
Each reflector is formed by alternately stacking a first reflection layer and a second reflection layer including oxide materials having different refractive indices,
The average thickness M1 of the reflective layer constituting the first reflection portion and the average thickness M2 of the reflective layer constituting the second reflection portion are M1 <M2,
The first reflection layer constituting the first reflection portion has a thickness of 50 to 90 nm, the first reflection layer constituting the second reflection portion has a thickness of 80 to 110 nm, and the second reflection layer constituting the first reflection portion is 30 to 60 nm. A nitride semiconductor light emitting device, characterized in that the second reflecting layer having a thickness, and forming a second reflecting portion has a thickness of 50 ~ 80 nm.
delete Substrate, n-type nitride layer, active layer, p-type nitride layer and
A distributed Bragg reflector formed by stacking a plurality of reflective layers below the substrate;
The distributed Bragg reflector includes a first reflecting portion, a second reflecting portion, and a third reflecting portion from below,
Each reflector is formed by alternately stacking a first reflection layer and a second reflection layer including oxide materials having different refractive indices,
The average thickness M1 of the reflective layer constituting the first reflection portion, the average thickness M2 of the reflective layer constituting the second reflection portion, and the average thickness M3 of the reflective layer constituting the third reflection portion are M1 <M2 <M3,
The first reflection layer constituting the first reflection portion has a thickness of 50 to 90 nm, the first reflection layer constituting the second reflection portion has a thickness of 80 to 110 nm, and the first reflection layer constituting the third reflection portion is 90 to 135 nm. The thickness of the second reflection layer constituting the first reflection portion is 30 to 60 nm, the second reflection layer constituting the second reflection portion is 50 to 80 nm and the thickness of the second reflection layer constituting the third reflection portion is 60 A nitride semiconductor light emitting device comprising a thickness of ˜90 nm.
delete The method according to claim 1 or 3,
The first reflective layer is made of a material having a refractive index of 1.2 ~ 1.5, the second reflective layer is a nitride semiconductor light emitting device, characterized in that made of a material having a refractive index of 2.0 ~ 3.0.
The method of claim 5,
The first reflective layer is made of SiO _X (1≤X≤3) or MgF ₂ , the second reflective layer is made of TiO _x (1≤X≤3) or ZrO ₂ .
delete delete The method of claim 1,
An average thickness of the first reflection layer constituting the first reflecting portion is 55 to 85 nm, the average thickness of the first reflection layer constituting the second reflecting portion is 85 to 105 nm.
The method of claim 1,
The average thickness of the second reflective layer forming the first reflecting portion is 35 to 55 nm, the average thickness of the second reflective layer forming the second reflecting portion is 55 to 75 nm.
delete delete The method of claim 3,
The average thickness of the first reflection layer constituting the first reflection portion is 55 to 85 nm, the average thickness of the first reflection layer constituting the second reflection portion is 85 to 105 nm, and the average thickness of the first reflection layer constituting the third reflection portion is 95 to 85 nm. A nitride semiconductor light emitting device, characterized in that 115nm.
The method of claim 3,
The average thickness of the second reflecting layer forming the first reflecting portion is 35 to 55 nm, the average thickness of the second reflecting layer forming the second reflecting portion is 55 to 75 nm, and the average thickness of the second reflecting layer forming the third reflecting portion is 65 to 55 nm. A nitride semiconductor light emitting device, characterized in that 85 nm.
The method according to claim 1 or 3,
A nitride light emitting device, characterized in that the uppermost reflective layer in contact with the substrate is made of TiO _x (1≤X≤3).
The method according to claim 1 or 3,
The distribution Bragg reflector is a nitride semiconductor light emitting device, characterized in that it comprises a reflection layer of 20 to 80 layers.
The method according to claim 1 or 3,
The substrate is a nitride semiconductor light emitting device, characterized in that made of at least one compound selected from sapphire, SiC, Si, GaN, ZnO, GaAs, GaP, LiAl ₂ O ₃ , BN and AlN.
The method according to claim 1 or 3,
The distribution Bragg reflector is a nitride semiconductor light emitting device, characterized in that for showing a light reflectance of more than 90% to 400 ~ 700 nm wavelength light.
The nitride light emitting device according to claim 1 or 3; And
And a light emitting element emitting light having a wavelength different from that emitted from the nitride light emitting device.
20. The method of claim 19,
The light emitting device is a white light emitting device, characterized in that the YAG-based yellow phosphor (yellow phosphor).
20. The method of claim 19,
A white light emitting device, characterized in that the color rendering index (CRI) of the emitted light is 85 or more.
A light emitting device package comprising the white light emitting device of claim 19.
A lighting device comprising the light emitting device package of claim 22.
Stacking a plurality of reflective layers on a lower surface of the substrate to form a distributed Bragg reflector; And
Forming an n-type nitride layer, an active layer, and a p-type nitride layer on an upper surface of the substrate,
In the forming of the distribution Bragg reflector, the first reflecting portion and the second reflecting portion are formed from the bottom, and the first reflecting layer and the second reflecting layer made of oxide materials having different refractive indices are alternately repeated to form each reflecting portion,
The average thickness M1 of the reflective layer constituting the first reflecting portion and the average thickness M2 of the reflective layer constituting the second reflecting portion are formed to be M1 <M2,
The first reflection layer constituting the first reflection portion has a thickness of 50 to 90 nm, the first reflection layer constituting the second reflection portion has a thickness of 80 to 110 nm, and the second reflection layer constituting the first reflection portion is 30 to 60 A method of manufacturing a nitride semiconductor light emitting device, characterized in that the second reflecting layer having a thickness of nm, and forming a second reflecting portion has a thickness of 50 ~ 80 nm.
delete Stacking a plurality of reflective layers on a lower surface of the substrate to form a distributed Bragg reflector; And
Forming an n-type nitride layer, an active layer, and a p-type nitride layer on an upper surface of the substrate,
In the step of forming the distributed Bragg reflector, the first reflecting portion, the second reflecting portion, and the third reflecting portion are formed from the bottom, and the first and second reflecting layers made of oxide materials having different refractive indices are alternately repeatedly laminated to each other. Form a reflector,
The average thickness M1 of the reflective layer constituting the first reflection portion, the average thickness M2 of the reflective layer constituting the second reflection portion, and the average thickness M3 of the reflective layer constituting the third reflection portion are M1 <M2 <M3,
The first reflection layer constituting the first reflection portion has a thickness of 50 to 90 nm, the first reflection layer constituting the second reflection portion has a thickness of 80 to 110 nm, and the first reflection layer constituting the third reflection portion is 90 to 135 nm. The second reflection layer forming the first reflection portion has a thickness of 30 to 60 nm, the second reflection layer forming the second reflection portion has a thickness of 50 to 80 nm, and the second reflection layer forming the third reflection portion. The method of manufacturing a nitride semiconductor light emitting device, characterized in that to exhibit a thickness of 60 ~ 90 nm.
delete The method of claim 24 or 26,
The first reflective layer is made of a material having a refractive index of 1.2 ~ 1.5, the second reflective layer is a method of manufacturing a nitride semiconductor light emitting device, characterized in that made of a material having a refractive index of 2.0 ~ 3.0.
29. The method of claim 28,
The first reflective layer is made of SiO _X (1≤X≤3) or MgF ₂ , the second reflective layer is made of TiO _x (1≤X≤3) or ZrO ₂ . Way.
The method of claim 24 or 26,
The first reflection layer and the second reflection layer is a plasma enhanced chemical vapor deposition (PECVD) method, a sputtering method, a MOCVD method or an electron beam evaporation (e-beam evaporation) method of manufacturing a nitride semiconductor light emitting device.

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