KR20140094807A - Light Emitting device using electron barrier layer - Google Patents

Light Emitting device using electron barrier layer Download PDF

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KR20140094807A
KR20140094807A KR1020130007298A KR20130007298A KR20140094807A KR 20140094807 A KR20140094807 A KR 20140094807A KR 1020130007298 A KR1020130007298 A KR 1020130007298A KR 20130007298 A KR20130007298 A KR 20130007298A KR 20140094807 A KR20140094807 A KR 20140094807A
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layer
barrier layer
barrier
atmosphere
semiconductor
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KR1020130007298A
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Korean (ko)
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유홍재
김경해
이주엽
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서울바이오시스 주식회사
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/025—Physical imperfections, e.g. particular concentration or distribution of impurities
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/14—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure
    • H01L33/145—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure with a current-blocking structure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/26—Materials of the light emitting region
    • H01L33/30—Materials of the light emitting region containing only elements of Group III and Group V of the Periodic Table
    • H01L33/32—Materials of the light emitting region containing only elements of Group III and Group V of the Periodic Table containing nitrogen

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  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Led Devices (AREA)

Abstract

A light emitting device according to the present invention includes a first semiconductor layer, an active layer, and a second semiconductor layer. The light emitting device includes an electron blocking layer placed between the second semiconductor layer and the active layer. The electron blocking layer includes a sub barrier layer and a first barrier layer which is formed on the sub barrier layer. The first barrier layer has a low energy bandgap of the sub barrier layer and is a IV group compound semiconductor. The light emitting device improves luminous efficiency by including the electron blocking layer to block an electron and to easily inject a hole by increasing an energy bandgap barrier to make the electron overflow by forming a plurality of electron blocking layers.

Description

(Light Emitting Device using electron barrier layer)

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device, and more particularly to a light emitting device in which holes are easily moved and an electron blocking layer (EBL) for blocking electrons is formed in a plurality of layers to improve luminous efficiency.

Semiconductor optical devices such as light emitting diodes (LEDs), laser diodes, photodetectors, or solar cells have a basic structure in which a light emitting layer is bonded between a p-type semiconductor layer and an n-type semiconductor layer. When a forward voltage is applied, It operates on the principle that electrons recombine and emit light.

In order to satisfy the performance such as brightness and reliability of the semiconductor light emitting device, a fundamental technical approach is to improve the internal quantum efficiency of the light emitting layer during epi-wafer growth.

In order to improve the internal quantum efficiency, the InGaN / GaN or InGaN / InGaN single quantum well (SQW) structure is applied to the light emitting layer. In order to meet the reliability demands such as lifetime and static electricity, Structure is changed to AlInGaN multi quantum well layer (MQW) structure and commercialized.

As such, a n / p- [AlGaN / GaN] super lattice layer is applied with a light emitting layer sandwiched between the luminescent layer itself and the luminescent layer itself.

However, in the light emitting device, the device is formed such that the concentration of electrons is relatively higher than the concentration of holes, and an electron blocking layer is further formed to reduce the imbalance in the hole concentration, thereby increasing the internal quantum efficiency and decreasing the leakage current of electrons .

FIG. 1 is a view showing a conventional light emitting device, and FIG. 2 is a view showing an energy band gap of the prior art of FIG.

1 and 2, a gallium nitride (GaN) -based light emitting device includes a substrate 110, an N layer 120 of n-type GaN, a light emitting layer 130, an electron blocking layer (EBL) 140, And a single crystal epitaxial structure such as a P layer 150 of GaN or the like.

In the light emitting device 100, the concentration of electrons in the N layer 120 is basically high because of the material properties of gallium nitride. In addition, since the concentration of electrons is relatively higher than that of holes, a leakage current of electrons occurs in the direction of the P layer 150.

As shown in the drawing, the electron blocking layer (EBL) 140 is disposed as a single layer between the light emitting layer 130 and the P layer 150 to prevent blocking of electrons leaking toward the P layer 150 ), The electrons are confined in the light emitting layer 130 to increase the recombination rate of light.

2, an energy band gap A 'of the N layer 120 is formed, and a D' energy band gap region of the P layer 150 and a B 'energy band gap region of the light emitting layer 130 are formed. An electron blocking layer 140 is formed. However, as in the energy band gap region of the electron blocking layer 140 of C ', the energy barrier is formed to be high.

As described above, electrons toward the P layer 150 can be blocked due to the action barrier a 'of the energy band gap formed by the electron blocking layer 140, but conversely, The balance barrier b 'of the formed energy band gap blocks the hole from the P layer 150 to the region of the light emitting layer 130 to decrease the hole injection efficiency in the light emitting layer 130 .

Further, the thin film growth reproducibility for forming the single electron blocking layer 140 is insufficient, and the leakage current increases due to the decrease in crystallinity and the driving voltage is increased, thereby reducing the luminous efficiency of the light emitting device 100 .

It is an object of the present invention to provide an electron blocking layer capable of blocking electrons while easily injecting holes by increasing an effective energy band gap barrier in which electrons must overflow by forming a plurality of electron blocking layers, And a light emitting device capable of improving luminous efficiency.

Another problem to be solved by the present invention is to form an electron blocking layer at a low temperature that does not transmit thermal damage to the active layer and to form a second semiconductor layer at a high temperature to compensate the thermal energy of the electron blocking layer, And a light emitting device having improved luminous efficiency.

A light emitting device according to an embodiment of the present invention includes a first semiconductor layer, an active layer, and a second semiconductor layer, the light emitting device comprising: an electron blocking layer disposed between the second semiconductor layer and the active layer, Wherein the electron blocking layer comprises: a sub-barrier layer; A first barrier layer formed on the sub-barrier layer; The first barrier layer is formed to have a low energy band gap of the sub-barrier layer and is a quaternary compound semiconductor.

And a second barrier layer between the second semiconductor layer and the first barrier layer, wherein the second barrier layer has an energy band higher than an energy band of the sub-barrier layer.

Wherein the sub-barrier layer is formed of undoped-AlGaN having a low Al content.

The first barrier layer is formed of undoped AlInGaN.

The second barrier layer may include a first layer formed on the first barrier layer, a second layer formed on the first layer, and a third layer formed on the second layer, The first layer, the second layer, and the third layer are formed of Al x Ga 1 - x N, and have different Al concentrations.

The second barrier layer may include a first layer formed on the first barrier layer, a second layer formed on the first layer, and a third layer formed on the second layer, The first layer, the second layer and the third layer are formed of Al x Ga 1 - x N, and the doping densities of P-type dopants having holes as carriers are different from each other.

Wherein the P-type dopant is one of magnesium (Mg), zinc (Zn), and a compound thereof.

The P-type dopant is characterized in that the implantation amount is gradually increased from the first layer toward the third layer.

A compensation layer is further formed between the electron blocking layer and the second semiconductor layer.

A light emitting device according to another embodiment of the present invention includes a first semiconductor layer formed on a substrate, an active layer formed on the first semiconductor layer, a sub-barrier layer formed on the active layer in a first atmosphere and having an energy band, A first barrier layer formed in the second atmosphere on the sub-barrier layer and having a first energy band lower than the energy band of the sub-barrier layer, and a third barrier layer formed in the third atmosphere on the first barrier layer, And a second barrier layer having a second energy band having a higher energy band than the first barrier layer, wherein an energy barrier formed between the first energy band and the second energy band difference between the first barrier layer and the second barrier layer .

Here, the sub-barrier layer is formed of undoped-AlGaN and is formed to a thickness of 10 Å to 30 Å.

Here, the first atmosphere is characterized by using N 2 gas as a carrier gas in a gas atmosphere of NH 3 + N 2 at a temperature of 850 ° C. to 880 ° C., a pressure of 100 Torr.

The first barrier layer is formed of undoped InxAl1-x (Ga) N, and is formed to a thickness of 10 Å to 30 Å.

The second atmosphere is characterized by using N 2 gas as a carrier gas in a gas atmosphere of NH 3 + N 2 at a temperature of 750 ° C. to 880 ° C., a pressure of 100 Torr.

The third atmosphere is characterized by using N 2 gas as a carrier gas at a temperature of 850 ° C to 880 ° C, a pressure of 100 Torr, and a gas atmosphere of NH 3 + N 2 .

The second barrier layer is crystallized in the third atmosphere.

The second barrier layer may include a first layer formed on the first barrier layer, a second layer formed on the first layer, and a third layer formed on the second layer, The first layer, the second layer, and the third layer are formed of Al x Ga 1 - x N, and have different Al concentrations.

The first layer and the second layer are formed to a thickness of 10 Å to 30 Å, and the third layer is formed to a thickness of 90 Å to 120 Å.

A second semiconductor layer is further formed on the second barrier layer.

Wherein the second semiconductor layer comprises a compensation layer formed on the second barrier layer and formed in a fourth atmosphere, a first upper layer formed on the compensation layer and formed in a fifth atmosphere, And a second upper layer formed in the sixth atmosphere.

Here, the fourth atmosphere may be at a temperature of 970 캜 to 980 캜, a pressure of 200 Torr, NH 3 + H 2 , NH 3 + N 2 Or a gas atmosphere of NH 3 + N 2 + H 2 .

And the fourth atmosphere of the compensation layer recrystallizes the second barrier layer.

And the fifth atmosphere is performed at 940 캜 to 950 캜.

And the sixth atmosphere is performed at 910 캜 to 930 캜.

According to the embodiments of the present invention, the light emitting device has a structure in which the electron blocking layer is formed of a plurality of layers to increase an energy band gap barrier in which electrons must overflow, thereby facilitating the injection of holes, So that the light emitting efficiency can be improved.

According to another embodiment of the present invention, the light emitting device forms an electron blocking layer at a low temperature that does not transmit thermal damage to the active layer, compensates for the thermal energy of the electron blocking layer by forming the second semiconductor layer at a high temperature, Can be recrystallized to improve the luminous efficiency.

1 is a view showing a conventional light emitting device.
2 is a view showing an energy band gap of the light emitting device of the prior art of FIG.
3 is a cross-sectional view illustrating a light emitting device according to a first embodiment of the present invention.
Fig. 4 is a diagram showing the energy band diagram of Fig. 3. Fig.
5A is a cross-sectional view illustrating an electron blocking layer of a light emitting device according to an embodiment of the present invention.
5B is a flowchart illustrating a process of forming an electron blocking layer of a light emitting device according to an embodiment of the present invention.
6A is a cross-sectional view of a second semiconductor layer according to an embodiment of the present invention.
6B is a flowchart illustrating a process of forming a second semiconductor layer according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided by way of example so that those skilled in the art can sufficiently convey the spirit of the present invention. Therefore, the present invention is not limited to the embodiments described below, but may be embodied in other forms. In the drawings, the width, length, thickness, etc. of components may be exaggerated for convenience. It is also to be understood that when an element is referred to as being "above" or "above" another element, But also includes the case where there are other components in between. Like reference numerals designate like elements throughout the specification.

First, a light emitting device according to embodiments of the present invention will be described with reference to FIGS. 3 to 6B. In the present embodiments, a light emitting device including a gallium nitride (GaN) semiconductor is described, but not limited thereto, various nitride semiconductors can be used.

FIG. 3 is a cross-sectional view illustrating a light emitting device according to an embodiment of the present invention, and FIG. 4 is a diagram illustrating an energy band diagram of FIG.

3 and 4, a light emitting device 30 according to an embodiment of the present invention includes a first semiconductor layer 33 formed on a substrate 31, an active layer 33 formed on a first semiconductor layer 33, And an electron blocking layer 300 formed on the active layer 35. The active layer 35 may include a second semiconductor layer 37 on the active layer 35. [

The substrate 31 is a growth substrate for fabricating the light emitting element 30 and is made of a nitride semiconductor such as Al 2 O 3 , SiC, ZnO, Si, GaAs, GaP, LiAl 2 O 3 , BN, AlN, The substrate is not particularly limited.

The nitride based light emitting device 30 may further include a buffer layer (not shown) between the substrate 31 and the first semiconductor layer 33. The buffer layer may use a nitride semiconductor of AlN or GaN to alleviate the lattice mismatch between the substrate 31 and the first semiconductor layer 33.

The first and second semiconductor layers 33 and 37 and the active layer 35 are formed of a nitride-based semiconductor and are not particularly limited. For example, the first and second semiconductor layers 33 and 37 and the active layer 35 may be formed of a two-component system such as GaN or InN, a three- Nitride semiconductor.

The first semiconductor layer 33 may be an N-type nitride-based semiconductor doped with Si or the like as an impurity to make electrons into carriers. In the structure of the gallium nitride (GaN) based light emitting device, the concentration of electrons in the first semiconductor layer 33 may be higher than the concentration of holes in the material characteristic of the nitride-based semiconductor.

The active layer 35 is formed on the first semiconductor layer 33. The active layer 35 is a layer that emits light through recombination of electrons and holes. As in the region A in Fig. 4, the active layer 35 that confines electrons to a plurality of layers can be formed to improve the recombination ratio. The active layer 35 may be formed of, for example, InGaN / GaN, InAlGaN / GaN or the like. Here, the uppermost layer of the active layer 35 may be formed of gallium nitride (GaN). The well layer and the barrier layer may be undoped semiconductor layers.

The second semiconductor layer 37 is formed on the active layer 35. The second semiconductor layer 37 may be a P-type nitride semiconductor in which the second semiconductor layer 37 has a hole as a carrier. A P-type dopant is doped to form holes in the second semiconductor layer 37, and magnesium (Mg) and zinc (Zn) may be used as the P-type dopant.

An electron blocking layer 300 is formed between the second semiconductor layer 37 and the active layer 35. The electron blocking layer 300 prevents the electrons provided in the first semiconductor layer 33 from flowing into the second semiconductor layer 37 while the holes provided in the second semiconductor layer 37 serve as the active layer 35 So that the inflow can be facilitated.

The EBL-electron blocking layer 300 according to the present invention includes a sub-barrier layer 305, a first barrier layer 310, and a second barrier layer 320. The sub-barrier layer 305, the first barrier layer 310 and the second barrier layer 320 may be formed of a plurality of nitride-based semiconductor layers each having a constant energy bandgap corresponding to the regions B, C, and D . Here, the electron blocking layer 300 includes a sub-barrier layer 305 having an energy band gap in the B region, a first barrier layer 310 having an energy band gap in the C region, and a first barrier layer 310 having an energy band gap in the D region. The second barrier layer 320, and the like.

A sub-barrier layer 305 is formed on the active layer 35. The sub-barrier layer 310 is disposed adjacent to the last layer of the active layer 35. The sub-barrier layer 305 has the same energy bandgap as that in the region B of FIG. 4 and can serve as a reference for forming the energy band gap of the first barrier layer 310.

The sub-barrier layer 305 can relax the strain caused by the lattice mismatch occurring in the active layer by forming the AlGaN semiconductor layer. The sub-barrier layer 305 preferably has a value between the barrier layer in the active layer 35 adjacent to the sub-barrier layer 305 and the energy band gap of the second barrier layer 320.

At this time, the sub-barrier layer 305 may have an undoped semiconductor layer. In the case of doping, deterioration of the crystallinity of the sub-barrier layer 305 and diffusion of doped impurities into the active layer 35 may lower the luminous efficiency.

A first barrier layer 310 is formed on the sub-barrier layer 305. The first barrier layer 310 may be grown with an undoped In x Al 1 -x (Ga) N type quaternary compound semiconductor.

At this time, the first barrier layer 310 has an energy band gap lower than the energy band gap of the sub-barrier layer 305 and a higher energy band gap than the well layer of the active layer, based on the energy band of the sub-barrier layer 305 As shown in FIG.

When the energy band gap of the first barrier layer 310 is higher than that of the second barrier layer 320, holes may not be smoothly injected into the active layer. Further, when the energy band gap is lower than the energy band gap of the active layer 35, the second barrier layer 320 to be described later may not easily grow, or the luminescence efficiency may be lowered due to lattice mismatching with the active layer 35.

At this time, the first barrier layer 310 may have an undoped semiconductor layer in the same manner as the sub-barrier layer 305, but is not limited thereto and may be doped at a lower concentration than the sub-barrier layer 305 .

Alternatively, if the sub-barrier layer 305 has a relatively thin thickness, the first barrier layer 310 is preferably undoped to prevent impurities from diffusing into the active layer 35.

A second barrier layer 320 may be further formed on the first barrier layer 310. The second barrier layer 320 may be formed of a plurality of layers of Al x Ga 1 - x N. The energy band gap of the second barrier layer 320 may be formed in a gradual shape and may be formed in a discrete stepped shape as shown in FIG. Here, the energy band can be formed in a stepped shape rising or descending from the second semiconductor layer 37 toward the active layer 35 so that the hole can be easily moved by adjusting the aluminum composition.

Here, the sub-barrier layer 305 and the second barrier layer 320 may not have a substantial difference in the energy bandgap due to the difference in aluminum composition. However, due to the first barrier layer 310 disposed between the sub-barrier layer 305 and the second barrier layer 320, the relative energy band gap difference between the first barrier layer 310 and the second barrier layer 320 a) can be largely formed.

Therefore, the energy barrier formed by the relative energy bandgap difference (a) can block electrons flowing into the second semiconductor layer 37 from the first semiconductor layer 33 through the active layer 35.

Holes are introduced into the active layer 35 through the first barrier layer 310 and the sub-barrier layer 305 in the second barrier layer 320. At this time, the energy barrier formed by the sub-barrier layer 305 in the first barrier layer 310 is formed to be low, and the holes are hopped.

Therefore, the holes provided in the second semiconductor layer 37 can be easily introduced into the active layer 35.

As described above, the light emitting device 30 according to the present invention can block the electrons by increasing the relative energy band gap barrier in which electrons must overflow by forming the electron blocking layer 300 as a plurality of layers, An electron blocking layer 300 is provided to improve the luminous efficiency.

Meanwhile, the second barrier layer 320 according to the present invention may be formed in the form of AlGaN: Mg to improve the concentration of holes. The second barrier layer 320 may be formed of a plurality of layers to control the concentrations of the aluminum component and the magnesium (Mg) component as a dopant. The adjustment of the concentration of aluminum is as described above.

Therefore, in the present invention, the concentration of holes can be increased by injecting a P-type dopant into the electron blocking layer 300. Here, the concentration of the magnesium component used as a dopant may be controlled. At this time, the second barrier layer 320 adjacent to the active layer 35 may be formed by injecting a dopant injection amount at a low concentration and gradually increasing the dopant injection amount while laminating the second barrier layer 320.

This is because dopant magnesium may be diffused and injected into the active layer 35 while the dopant is being injected. Since the efficiency of light emission may be reduced due to magnesium diffused in the active layer 35, The dopant of the second barrier layer 320 is preferably formed at a low concentration. In addition, it is possible to prevent the lowering of luminous efficiency due to indium in the first barrier layer 305 which prevents diffusion of the dopant.

Therefore, according to the present invention, the energy bandgap of each layer of the electron blocking layer 300 formed of a plurality of layers formed on the active layer 35 in designing the electron blocking layer 300 of the light emitting device 30 is controlled The leakage of the electrons is blocked, and the flow of holes is improved, so that the operating voltage can be lowered and the light output can be improved. Further, by increasing the concentration of the holes by adjusting the P-type dopant concentration by using the superlattice structure in the electron blocking layer 300, it is possible to improve the luminous efficiency by reducing the concentration imbalance of electrons and holes.

FIG. 5A is a cross-sectional view illustrating an electron blocking layer of a light emitting device according to an embodiment of the present invention, and FIG. 5B is a flowchart illustrating a process of forming an electron blocking layer of a light emitting device according to an embodiment of the present invention. Hereinafter, a nitride-based light emitting device according to an embodiment of the present invention will be described with reference to FIGS. 3 to 4. FIG.

The method of manufacturing the light emitting device 30 according to the present invention can be collectively grown in one reactor, and the light emitting device can be formed by changing the atmosphere and growth temperature of the carrier gas.

First, a flow of a process of forming the light emitting device 30 will be schematically described. A first semiconductor layer 33 is formed on a substrate 31. [ At this time, a buffer layer (not shown) may be further formed to relieve the stress caused by the lattice mismatch between the substrate 31 and the first semiconductor layer 33. At this time, the first semiconductor layer 33 is formed of NH 3 + H 2 + N < 2 >.

Then, the active layer 35 is formed on the first semiconductor layer 33. Here, the active layer 35 may be formed of a plurality of layers, and the last layer of the active layer 35 formed of a plurality of layers may be formed of gallium nitride (GaN). An electron blocking layer 300 formed of a sub barrier layer 305, a first barrier layer 310 and a second barrier layer 320 is formed on the active layer 35, The second semiconductor layer 37 is formed.

The active layer 35 is formed on the substrate 31 on which the first semiconductor layer 33 is formed. The active layer 35 can be grown into a plurality of layers to improve internal quantum efficiency. As a result, electrons can be confined in the active layer 35 to improve the luminous efficiency. In other words, electrons can be formed so as to stay in the active layer 35 region due to a plurality of energy band gaps formed in a plurality of layers.

Here, the active layer 35 can be formed in a gas atmosphere of NH 3 + N 2 . The active layer 35 may use a carrier gas as an N 2 gas, and may be formed at a pressure of 300 to 500 Torr at 750 ° C to 880 ° C.

The electron blocking layer 300 is formed on the active layer 35 thus formed. The electron blocking layer 300 may be formed of a plurality of layers by controlling the forming atmosphere. By forming a plurality of electron blocking layers 300 in this way, electrons can be prevented from flowing into the second semiconductor layer 37. The light emitting device 30 may be realized by forming a second semiconductor layer 37 on the electron blocking layer 300 and connecting the electrodes to the semiconductor layers 33 and 37.

In forming the light emitting element 30 as described above, the electron blocking layer 300, which is formed of a plurality of layers and can be crystallized by changing the growth temperature and the growth pressure of each layer to prevent damage to the active layer, .

5A and 5B, after the active layer 35 is formed, the electron blocking layer 300 is formed of a plurality of layers. Here, in order to avoid redundant description, description will be made with reference to FIG. 3 and FIG.

The sub-barrier layer 305 may be formed in the first atmosphere on the active layer 35, as in step S110. Here, the sub-barrier layer 305 may be formed to a thickness of 10 ANGSTROM to 30 ANGSTROM as undoped-AlGaN.

Here, the first atmosphere may be N 2 gas as a carrier gas in a gas atmosphere of NH 3 + N 2 at a temperature of 850 ° C. to 880 ° C., a pressure of 100 Torr.

The reason why the sub-barrier layer 305 is formed in the first atmosphere is that when the temperature of the active layer 35 is higher than the formation temperature of the active layer 35 (750 ° C to 880 ° C), the active layer 35 is thermally damaged, . Therefore, the sub-barrier layer 305 formed adjacent to the active layer 35 is preferably formed in the first atmosphere.

3 and 4, the sub-barrier layer 305 is formed of AlGaN. At this time, the aluminum (Al) component is formed at a low concentration so that the last layer and the energy band of the active layer 35 are spaced apart from each other by a predetermined interval So that the gap can be formed.

On the other hand, as the active layer 35 is formed of a plurality of layers so as to serve as a receptacle for electrons, the active layer 35 itself may be strained. A strong electric field due to the piezoelectric effect is generated in the active layer 35 due to the strain due to the large lattice mismatch of the active layer 35 itself and the wave function of the electron-hole carrier is separated, Problems can arise. Such an internal electric field may cause limitation of the number of well layers in the Al composition and the multiple quantum well structure used in the active layer 35, thereby limiting the output of the light emitting device.

Therefore, in the present invention, by forming the sub-barrier layer 305 formed of AlGaN, the strain in the active layer 35 can be relaxed.

The energy bandgap between the energy band gap of the second semiconductor layer 37 and the energy band gap of the active layer 35 is lower than that of the second semiconductor layer 37 on the sub-barrier layer 305, The first barrier layer 310 is formed. At this time, the first barrier layer 310 may be formed of InxAl 1-x (Ga) N having a thickness of 10 Å to 30 Å in the second atmosphere.

Here, the second atmosphere may be a temperature of 750 ° C to 880 ° C to form an active layer N 2 gas can be used as a carrier gas in a gas atmosphere of NH 3 + N 2 at a pressure of 100 Torr which is relatively lower than that at the time of sputtering.

The first barrier layer 310 may be formed of an undoped material in which a lattice match (LM) occurs in a nitrogen gas atmosphere free of hydrogen for the incorporation of indium elements. A layer of InxAl1-x (Ga) N type can be grown. Since the four-component material can change the lattice constant and the energy band gap independently, the energy band gap of the first barrier layer 310 can be reduced.

Here, the indium (In) component of the first barrier layer 310 can be volatilized when grown at a high growth temperature. Therefore, it is preferable to form the first barrier layer 310 at the temperature and the pressure of the second atmosphere.

In step S130, a second barrier layer 320 is formed on the first barrier layer 310 in a third atmosphere. The second barrier layer 320 may be formed of one or more layers. The second barrier layer 320 formed in contact with the second semiconductor layer 37 may be formed of a material having a high energy band gap to prevent electrons from overflowing from the active layer 35 to the second semiconductor layer 37. [ Can be used.

Here, the third atmosphere may be N 2 gas as a carrier gas at a temperature of 850 ° C to 880 ° C, a pressure of 100 Torr, and a gas atmosphere of NH 3 + N 2 . The third atmosphere may be the same atmosphere as the first atmosphere. Under the third atmospheric condition, the second barrier layer 320 may be precrystallized.

The second barrier layer 320 may be formed of a plurality of layers. Where a layer adjacent to the first barrier layer is referred to as a first layer 322, a layer formed on the first layer 322 is referred to as a second layer 325, a second layer 325 Will be described below as the third layer 327. [0150]

The second barrier layer 320 is formed of Al x Ga 1 - x N. By adjusting the concentration of the aluminum component, the energy band gap is controlled to prevent the electron from overflowing, can do. In this way, the concentration of Al in the second barrier layer 320 can be controlled to control the energy bandgap. The relative energy band gap (a) between the first barrier layer 310 and the second barrier layer 320 can be increased by adjusting the concentration of Al. In addition, the concentration of Al can be adjusted to control the energy band gap so that the holes provided in the second semiconductor layer 37 can be transferred to the active layer 35 and injected easily.

On the other hand, the second barrier layer 320 may be doped with impurities to form a P-type second barrier layer 320 to reduce concentration unbalance between electrons and holes. At this time, the P-type second barrier layer 320 can be formed using magnesium (Mg) as a dopant.

Here, the second barrier layer 320 can be formed by adjusting the concentration of the dopant. The second barrier layer 320 may control the dopant concentration so that the first layer 322 adjacent to the active layer 35 may have a low dopant concentration. The third layer 327 adjacent to the second semiconductor layer 37 may have a high dopant concentration.

And the second layer 325 may gradually implant the concentration of the dopant so that the intermediate concentration between the first layer 322 and the third layer 327 may be injected. At this time, the first layer 322 and the second layer 325 may be formed to a thickness of 10 ANGSTROM to 30 ANGSTROM, and the third layer 327 may be formed to a thickness of 90 ANGSTROM to 120 ANGSTROM to improve the concentration of holes.

On the other hand, a large amount of crystal defects such as V-pits are present on the surface of AlInGaN constituting the first barrier layer 310 or the active layer 35, and a second barrier layer The pit formed on the surface of the first barrier layer 310 or the active layer 35 becomes a channel for crystal defects and magnesium atoms are diffused into the active layer 35 through inter diffusion, The light emitting efficiency may be lost.

Therefore, the second barrier layer 320 contacting the first barrier layer 310 can inject a dopant in a region adjacent to the active layer 35, that is, the first layer 322 at a low concentration. That is, the second barrier layer 320 has a low dopant concentration in the region adjacent to the active layer 35 and the second barrier layer 320 adjacent to the second semiconductor layer 37, that is, the third layer 327, The concentration of the dopant can be increased.

As described above, by increasing the concentration of holes through the second barrier layer 320, the concentration imbalance of holes and electrons is reduced and the energy band gap is controlled to overflow the active layer 35 to the second semiconductor layer 37 It has an effect of blocking electrons.

Therefore, the electron blocking layer 300 can be formed in different atmospheres to prevent thermal damage to the active layer 35 while preventing leakage of electrons and facilitating hole injection, thereby improving the luminous efficiency of the light emitting device 30 .

6A is a cross-sectional view of a second semiconductor layer according to an embodiment of the present invention, and FIG. 6B is a flowchart illustrating a process of forming a second semiconductor layer according to an embodiment of the present invention. 3, 4, 5A and 5B will be described in order to avoid redundant description.

6A and 6B, the second semiconductor layer 320 may be formed on the electron blocking layer 300 after the electron blocking layer 300 is formed. Specifically, the second semiconductor layer 37 may be formed on the second barrier layer 320 of the electron blocking layer 300. The second semiconductor layer 37 may be formed of a P-type semiconductor layer and serve to provide holes to the active layer 35. Here, the second semiconductor layer 37 can be formed in the fourth, fifth, and sixth mines.

The second semiconductor layer 37 is formed on the second barrier layer 320 such that the second semiconductor layer 37 has the compensation layer 37a and the compensation layer 37a on the compensation layer 37a, And an upper layer 37b formed thereon. The compensation layer 37a may be formed between the second barrier layer 320 and the upper layer 37b.

The compensation layer 37a may be disposed between the second semiconductor layer 37 and the electron blocking layer 300 and the compensation layer 37a of the second semiconductor layer 37 may be formed in the fourth atmosphere.

The fourth atmosphere may be at a temperature of 970 캜 to 980 캜, a pressure of 200 Torr, NH 3 + H 2 , NH 3 + N 2 Or a gas atmosphere of NH 3 + N 2 + H 2 .

The conventional AlGaN growth temperature is generally 1000? The crystallinity can be improved. However, in order to prevent thermal damage to the active layer 35, the third layer 327 of the electron blocking layer 300 is grown at a low temperature lower than the AlGaN growth temperature to be crystallized.

Therefore, in order to prevent thermal damage of the active layer 35, AlGaN has to be formed at a high temperature to improve crystallinity. In the present invention, the crystallinity of the electron blocking layer 300 is lowered .

Therefore, in the present invention, the compensating layer 37a adjacent to the electron blocking layer 300 is changed to 970? To 980? The electron blocking layer 300 formed of AlGaN can be formed in a high-temperature fourth atmosphere to be recrystallized. Thus, the electron blocking layer 300 disposed under the compensation layer 37a of the second semiconductor layer 37 can be recrystallized by receiving thermal energy.

As in step S220, an upper layer formed on the compensation layer is formed in a fifth atmosphere. The fifth atmosphere may be performed at 940 ° C to 950 ° C. Here, the upper layer is referred to as a first upper layer in order to distinguish the upper layer formed in the fifth atmosphere from the upper layer formed in the fifth atmosphere.

Then, as in the step of S230, the second upper layer on the first upper layer is divided into a sixth atmosphere 910? To 930 ?. In this manner, the second semiconductor layer 320 may be formed while gradually reducing the film forming process temperature, thereby minimizing the thermal damage of the light emitting device.

In this manner, the electron blocking layer 300 is formed at a low temperature not to transmit thermal damage to the active layer 35, the second semiconductor layer 37 is formed at a high temperature to compensate the thermal energy of the electron blocking layer 300 The electron blocking layer 300 can be recrystallized to improve the luminous efficiency.

30: light emitting element 31: substrate
33: first semiconductor layer 35: active layer
37: second semiconductor layer 300: electron blocking layer
305: sub-barrier layer 310: first barrier layer
320: second barrier layer

Claims (24)

A light emitting device comprising a first semiconductor layer, an active layer, and a second semiconductor layer,
And an electron blocking layer disposed between the second semiconductor layer and the active layer,
Wherein the electron blocking layer
A sub-barrier layer;
A first barrier layer formed on the sub-barrier layer;
Wherein the first barrier layer is formed to have a low energy band gap of the sub-barrier layer, and is a quaternary compound semiconductor.
The method according to claim 1,
And a second barrier layer between the second semiconductor layer and the first barrier layer,
Wherein the second barrier layer comprises:
And has an energy band higher than an energy band of the sub-barrier layer.
The method according to claim 1,
And the sub-barrier layer is formed of undoped-AlGaN having a low Al content.
The method according to claim 1,
Wherein the first barrier layer is formed of undoped-AlInGaN.
3. The method of claim 2,
Wherein the second barrier layer comprises:
A first layer formed on the first barrier layer;
A second layer formed on the first layer; And
A third layer formed on the second layer; ≪ / RTI >
Wherein the first layer, the second layer and the third layer are formed of Al x Ga 1 - x N, and the concentrations of Al are different from each other.
3. The method of claim 2,
Wherein the second barrier layer comprises:
A first layer formed on the first barrier layer;
A second layer formed on the first layer; And
A third layer formed on the second layer; ≪ / RTI >
Wherein the first layer, the second layer, and the third layer are formed of Al x Ga 1 - x N, and the doping densities of the P-type dopants having holes as carriers are different from each other.
The method according to claim 6,
Wherein the P-type dopant is one of magnesium (Mg), zinc (Zn), and a compound thereof.
The method according to claim 6,
The P-
Wherein a dose of the light is gradually increased from the first layer toward the third layer.
The method according to claim 1,
And a compensating layer is further formed between the electron blocking layer and the second semiconductor layer.
A first semiconductor layer formed on a substrate;
An active layer formed on the first semiconductor layer;
A sub-barrier layer formed in the first atmosphere on the active layer and having an energy band;
A first barrier layer formed in the second atmosphere on the sub-barrier layer and having a first energy band lower than an energy band of the sub-barrier layer; And
A second barrier layer formed in the third atmosphere on the first barrier layer and having a second energy band having a higher energy band than the sub-barrier layer; ≪ / RTI >
And an energy barrier formed between the first barrier layer and the second barrier layer with the first energy band and the second energy band difference.
11. The method of claim 10,
Wherein the sub-barrier layer is formed of undoped-AlGaN and is formed to a thickness of 10 ANGSTROM to 30 ANGSTROM.
11. The method of claim 10,
Light-emitting device characterized by using N 2 gas from the first atmosphere is 850 to 880 ℃ ℃ temperature, a pressure of 100Torr, the gas atmosphere of NH 3 + N 2 as a carrier gas.
11. The method of claim 10,
Wherein the first barrier layer is formed of undoped InxAl1-x (Ga) N, and is formed to a thickness of 10A to 30A.
11. The method of claim 10,
Light-emitting device characterized in that the said second atmosphere, using N 2 gas at 750 ℃ to a temperature of 880 ℃, pressure of 100Torr, the gas atmosphere of NH 3 + N 2 as a carrier gas.
11. The method of claim 10,
Light-emitting device of the third atmosphere is characterized by using the N 2 gas at 850 ℃ to a temperature of 880 ℃, a pressure of 100Torr, the gas atmosphere of NH 3 + N 2 as a carrier gas.
16. The method of claim 15,
Wherein the second barrier layer is precrystallized in the third atmosphere.
11. The method of claim 10,
Wherein the second barrier layer comprises:
A first layer formed on the first barrier layer;
A second layer formed on the first layer; And
A third layer formed on the second layer; ≪ / RTI >
Wherein the first layer, the second layer and the third layer are formed of Al x Ga 1 - x N, and the concentrations of Al are different from each other.
18. The method of claim 17,
Wherein the first layer (322) and the second layer (325) are formed to a thickness of 10 ANGSTROM to 30 ANGSTROM, and the third layer (327) is formed to a thickness of 90 ANGSTROM to 120 ANGSTROM.
11. The method of claim 10,
And a second semiconductor layer is further formed on the second barrier layer.
20. The method of claim 19,
Wherein the second semiconductor layer comprises:
A compensation layer formed on the second barrier layer and formed in a fourth atmosphere;
A first upper layer formed on the compensation layer and formed in a fifth atmosphere; And
A second upper layer formed on the first upper layer and formed in a sixth atmosphere; Emitting element.
21. The method of claim 20,
The fourth atmosphere may be at a temperature of 970 캜 to 980 캜, a pressure of 200 Torr, NH 3 + H 2 , NH 3 + N 2 or NH 3 + N 2 + H 2 .
21. The method of claim 20,
Wherein the fourth atmosphere of the compensation layer
And recrystallizes the second barrier layer.
21. The method of claim 20,
And the fifth atmosphere is performed at 940 캜 to 950 캜.
21. The method of claim 20,
Lt; RTI ID = 0.0 > 910 C < / RTI > to < RTI ID = 0.0 > 930 C. < / RTI >
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KR20170000116A (en) * 2015-06-23 2017-01-02 엘지이노텍 주식회사 Light emitting device and light emitting device package having thereof
KR20180080592A (en) * 2017-01-04 2018-07-12 엘지이노텍 주식회사 Semiconductor device and light emitting device package having thereof
CN110494992A (en) * 2017-01-04 2019-11-22 Lg伊诺特有限公司 Semiconductor devices and light emitting device package including the semiconductor devices
CN116504894A (en) * 2023-06-27 2023-07-28 江西兆驰半导体有限公司 GaN-based LED epitaxial wafer, growth process thereof and LED

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20170000116A (en) * 2015-06-23 2017-01-02 엘지이노텍 주식회사 Light emitting device and light emitting device package having thereof
KR20180080592A (en) * 2017-01-04 2018-07-12 엘지이노텍 주식회사 Semiconductor device and light emitting device package having thereof
CN110494992A (en) * 2017-01-04 2019-11-22 Lg伊诺特有限公司 Semiconductor devices and light emitting device package including the semiconductor devices
EP3567642A4 (en) * 2017-01-04 2020-06-24 LG Innotek Co., Ltd. Semiconductor device and light emitting device package comprising same
US10971649B2 (en) 2017-01-04 2021-04-06 Lg Innotek Co., Ltd. Semiconductor device and light emitting device package comprising same
CN110494992B (en) * 2017-01-04 2022-11-01 苏州立琻半导体有限公司 Semiconductor device and light emitting device package including the same
CN116504894A (en) * 2023-06-27 2023-07-28 江西兆驰半导体有限公司 GaN-based LED epitaxial wafer, growth process thereof and LED
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