CN111261757A - Ultraviolet LED and preparation method thereof - Google Patents

Ultraviolet LED and preparation method thereof Download PDF

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Publication number
CN111261757A
CN111261757A CN202010078729.6A CN202010078729A CN111261757A CN 111261757 A CN111261757 A CN 111261757A CN 202010078729 A CN202010078729 A CN 202010078729A CN 111261757 A CN111261757 A CN 111261757A
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layer
quantum barrier
quantum
quantum well
structures
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万志
卓祥景
蔺宇航
尧刚
程伟
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Xiamen Changelight Co Ltd
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Xiamen Changelight Co Ltd
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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
    • H01L33/04—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 quantum effect structure or superlattice, e.g. tunnel junction
    • H01L33/06—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 quantum effect structure or superlattice, e.g. tunnel junction within the light emitting region, e.g. quantum confinement structure or tunnel barrier
    • 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
    • H01L33/005—Processes
    • H01L33/0062—Processes for devices with an active region comprising only III-V compounds
    • H01L33/0066—Processes for devices with an active region comprising only III-V compounds with a substrate not being a III-V compound
    • H01L33/007—Processes for devices with an active region comprising only III-V compounds with a substrate not being a III-V compound comprising nitride compounds
    • 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
    • H01L33/325—Materials of the light emitting region containing only elements of Group III and Group V of the Periodic Table containing nitrogen characterised by the doping materials

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Abstract

The embodiment of the application provides an ultraviolet LED and a manufacturing method thereof, wherein the LED comprises the following components: a substrate; a buffer layer; a current spreading layer; a multiple quantum well active layer; the superlattice electron blocking layer comprises a multi-quantum well active layer and a quantum well structure, wherein the quantum well active layer comprises a quantum barrier structure and the quantum well structure, the quantum barrier structure comprises a first quantum barrier layer, a second quantum barrier layer and a third quantum barrier layer, the Al component of the second quantum barrier layer is higher than the Al component of the first quantum barrier layer and the Al component of the third quantum barrier layer, so that the Al component in the quantum barrier structure is in a step shape, a high barrier is formed by the aid of the higher Al component of the second quantum barrier layer, a strong electron blocking effect is achieved, meanwhile, the stress between the quantum barrier structure and the quantum well structure is reduced by the aid of the lower Al components of the first quantum barrier layer and the third quantum barrier layer, a polarization electric field in the multi-quantum well active layer is weakened, the radiation recombination rate of the multi-quantum well active layer is improved, and the light emitting power of the ultraviolet LED is improved.

Description

Ultraviolet LED and preparation method thereof
Technical Field
The application relates to the technical field of semiconductor photoelectron, in particular to an ultraviolet LED and a preparation method thereof.
Background
In recent years, group III-V nitrides have been drawing attention in the electrical and optical fields because of their direct bandgap semiconductor properties, and they have excellent physical properties such as large forbidden bandwidth, high breakdown electric field, high electron saturation mobility, and the like. Among them, blue and white light emitting diodes using GaN-based as a main material have achieved efficiencies exceeding those of any conventional light source in the past, and are widely used in various emerging industries.
Ultraviolet LEDs have important applications in industrial curing, sterilization, environmental monitoring and the like due to unique physical and chemical characteristics, but the existing violet LEDs have lower luminous power.
Disclosure of Invention
In view of this, the embodiment of the present application provides an ultraviolet LED and a method for manufacturing the same, so as to improve the light emitting power of the ultraviolet LED.
In order to achieve the above purpose, the present application provides the following technical solutions:
an ultraviolet LED, comprising:
a substrate;
a buffer layer on the first surface of the substrate;
the current expansion layer is positioned on one side, away from the substrate, of the buffer layer;
the multiple quantum well active layer is positioned on one side, away from the buffer layer, of the current expansion layer and comprises M quantum barrier structures and N quantum well structures, M is a positive integer larger than 1, N is a positive integer larger than 1, and the quantum barrier structures and the quantum well structures are arranged in a staggered mode;
the superlattice electron blocking layer is positioned on one side, away from the current spreading layer, of the multi-quantum well active layer;
the quantum barrier structure comprises a first quantum barrier layer, a second quantum barrier layer and a third quantum barrier layer, wherein the Al component of the second quantum barrier layer is higher than the Al components of the first quantum barrier layer and the third quantum barrier layer.
Optionally, the current spreading layer is in contact with a quantum barrier structure in the multiple quantum well active layer.
Optionally, the superlattice electron blocking layer is in contact with a quantum barrier structure in the multiple quantum well active layer.
Optionally, aluminum components in the second quantum barrier layers in each of the M quantum barrier structures are the same.
Optionally, an aluminum component in the second quantum barrier layer in each of the M quantum barrier structures increases or decreases progressively along a first direction, and the current spreading layer points to the superlattice electron blocking layer in the first direction.
Optionally, the aluminum component in the quantum well structure is smaller than the aluminum component in the quantum barrier structure.
Optionally, the aluminum composition in the current spreading layer is smaller than the aluminum composition in the multiple quantum well active layer.
Optionally, the doping concentration range of the N-type doping in the quantum barrier structure is 3 × 1018cm-3～5x1018cm-3Inclusive.
Optionally, the thickness of the quantum barrier structure ranges from 10nm to 12nm, inclusive; the thickness of the quantum well structure ranges from 2nm to 3nm, inclusive.
A preparation method of an ultraviolet LED comprises the following steps:
step 1: forming a buffer layer on a first surface of a substrate;
step 2: forming a current spreading layer on one side of the buffer layer, which is far away from the substrate;
and step 3: forming a multi-quantum well active layer on one side, away from the buffer layer, of the current spreading layer, wherein the multi-quantum well active layer comprises M quantum barrier structures and N quantum well structures, M is a positive integer larger than 1, and N is a positive integer larger than 1, and the quantum barrier structures and the quantum well structures are arranged in a staggered mode;
and 4, step 4: forming a superlattice electron blocking layer on one side, away from the current spreading layer, of the multi-quantum well active layer;
the quantum barrier structure comprises a first quantum barrier layer, a second quantum barrier layer and a third quantum barrier layer, wherein the Al component of the second quantum barrier layer is higher than the Al components of the first quantum barrier layer and the third quantum barrier layer.
Optionally, a multiple quantum well active layer is formed on a side of the current spreading layer departing from the buffer layer, the multiple quantum well active layer includes M quantum barrier structures and N quantum well structures, M is a positive integer greater than 1, and N is a positive integer greater than 1, wherein the quantum barrier structures and the quantum well structures are arranged in a staggered manner, including:
and alternately forming quantum barrier structures and quantum well structures on the side, away from the buffer layer, of the current spreading layer so as to form M quantum barrier structures and N quantum well structures on the side, away from the buffer layer, of the current spreading layer, wherein M is greater than N by 1.
Optionally, the method for forming the quantum barrier structure includes:
step 401: growing a first quantum barrier layer by using an aluminum source with a first flow rate at a first rotating speed and a first pressure;
step 402: increasing the flow of the aluminum source to a second flow, and growing a second quantum barrier layer by using the aluminum source with the second flow;
step 403: and reducing the flow of the aluminum source to a third flow, and growing a third quantum barrier layer by using the aluminum source with the third flow.
Optionally, the growing the second quantum barrier layer by using the aluminum source with the second flow rate includes:
step 4011: introducing an aluminum source with a second flow rate in a first time period;
step 4012: stopping introducing the aluminum source in a second time period;
and repeating the step 4011 and the step 4012 until the growth of the second quantum barrier layer is completed.
Optionally, the value range of the first time period is 3s to 10s, including an endpoint value; the value range of the second time period is 3 s-10 s, including the endpoint value.
Optionally, the value range of the first pressure is 100torr to 200torr, including an endpoint value; the first rotation speed ranges from 200rpm to 300rpm, inclusive.
Optionally, the method for forming the quantum well structure includes:
and growing a quantum well structure on the surface of the quantum barrier structure at a second rotating speed and a second pressure, wherein the second rotating speed is greater than the first rotating speed, and the second pressure is greater than the first pressure.
In the ultraviolet LED provided by the embodiment of the present application, the quantum barrier structure includes a first quantum barrier layer, a second quantum barrier layer and a third quantum barrier layer, the Al component of the second quantum barrier layer is higher than the Al component of the first quantum barrier layer and the third quantum barrier layer, so that the Al component in the quantum barrier structure is in a step shape, a high barrier is formed by the higher Al component of the second quantum barrier layer to realize a stronger electron blocking effect, and the stress between the quantum barrier structure and the quantum well structure is reduced by using the first quantum barrier layer and the third quantum barrier layer having lower Al components, thereby weakening the polarization electric field in the multiple quantum well active layer, reducing the energy band bending in the multiple quantum well active layer, increasing the wave function overlapping of electrons and holes in the multiple quantum well active layer, and further improving the radiation recombination rate of the multiple quantum well active layer, and improving the luminous power of the ultraviolet LED.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of an ultraviolet LED provided in an embodiment of the present application;
fig. 2 is a schematic structural diagram of a quantum barrier structure in an ultraviolet LED according to an embodiment of the present disclosure;
fig. 3 is a schematic structural diagram of a quantum barrier structure in an ultraviolet LED according to another embodiment of the present disclosure;
FIG. 4 is a flow chart of a method for fabricating an ultraviolet LED according to one embodiment of the present application;
fig. 5 to fig. 11 are schematic structural diagrams after completion of each process step in a method for manufacturing an ultraviolet LED according to an embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application, but the present application may be practiced in other ways than those described herein, and it will be apparent to those of ordinary skill in the art that the present application is not limited to the specific embodiments disclosed below.
As described in the background section, the existing ultraviolet LEDs have a low luminous power.
Research shows that, heretofore, a purple light LED utilizes a very narrow part of an emission spectrum of a GaN-based material, and although light emission in the whole ultraviolet band can be realized by adding Al to the GaN-based material, due to the limitation of the production process level of the ultraviolet LED, large-scale application of the ultraviolet band still has many problems, such as serious electron leakage and insufficient hole injection, which results in low light emitting power of the existing ultraviolet LED. Moreover, AlGaN having a high Al composition is difficult to prepare, and as the wavelength is reduced, the technical limit thereof is more, the difficulty of growth is greater.
Therefore, reducing electron leakage, increasing hole injection, preparing high-quality AlGaN materials, and further improving the whole ultraviolet LED light emitting power become the problems to be solved urgently at present
In view of this, the embodiment of the present application provides an ultraviolet LED and a method for manufacturing the same. The ultraviolet LED and the method for manufacturing the same provided by the embodiments of the present application are described below with reference to the accompanying drawings.
Referring to fig. 1, an ultraviolet LED provided in an embodiment of the present application includes:
optionally, the substrate 1 is a sapphire substrate, such as a C-plane sapphire substrate, but this is not limited in this application, and is specifically determined as the case may be;
a buffer layer 2 on the first surface of the substrate 1;
a current spreading layer 3 located on a side of the buffer layer 2 facing away from the substrate 1;
the multiple quantum well active layer 4 is positioned on one side, away from the buffer layer 2, of the current spreading layer 3, the multiple quantum well active layer 4 comprises M quantum barrier structures 41 and N quantum well structures 42, M is a positive integer larger than 1, N is a positive integer larger than 1, and the quantum barrier structures 41 and the quantum well structures 42 are arranged in a staggered mode;
the superlattice electron blocking layer 5 is positioned on one side, away from the current spreading layer 3, of the multiple quantum well active layer 4, so that electron overflow in the multiple quantum well active layer is reduced by utilizing the superlattice electron blocking layer, and the light emitting efficiency of the LED chip is improved;
the quantum barrier structure 41 includes a first quantum barrier layer 411, a second quantum barrier layer 412, and a third quantum barrier layer 413, and an Al component of the second quantum barrier layer 412 is higher than Al components of the first quantum barrier layer 411 and the third quantum barrier layer 413.
On the basis of the above embodiments, in an embodiment of the present application, the buffer layer is an undoped a l N layer, and optionally, the thickness of the buffer layer ranges from 2.2 μm to 2.5 μm, inclusive, but the present application does not limit this, as the case may be.
On the basis of the above embodiment, in an embodiment of the present application, the buffer layer 2 includes:
a nucleation layer 21 on a first surface of said substrate 1;
a recrystallization layer 22 on the side of the nucleation layer 21 facing away from the substrate 1.
Based on the above embodiments, in one embodiment of the present application, the thickness of the nucleation layer ranges from 10nm to 50nm, inclusive; the thickness of the recrystallized layer ranges from 300nm to 400nm, inclusive.
It should be noted that, in the embodiments of the present application, the nucleation layer serves to provide nuclei for the growth of the subsequent epitaxial structure, so as to improve the quality of the subsequently grown epitaxial wafer.
Specifically, on the basis of any one of the above embodiments, in an embodiment of the present application, the nucleation layer is an undoped low-temperature nucleation layer, and the growth temperature of the nucleation layer ranges from 900 ℃ to 1000 ℃, inclusive; the recrystallization layer is a high-temperature crystallization layer, and the growth temperature of the recrystallization layer ranges from 1100 ℃ to 1200 ℃ inclusive; however, the present application is not limited thereto, as the case may be.
On the basis of the above embodiment, in an embodiment of the present application, the buffer layer 2 further includes:
a plurality of first aluminum nitride layers 23 and a plurality of second aluminum nitride layers 24 on a side of the recrystallization layer 22 facing away from the nucleation layer 21; the plurality of first aluminum nitride layers 23 and the plurality of second aluminum nitride layers 24 are alternately arranged, and the growth temperatures of the first aluminum nitride layers 23 and the second aluminum nitride layers 24 are different, so that a high-quality aluminum nitride layer is obtained, lattice mismatch between the substrate and a subsequently grown current expansion layer is reduced, dislocation is reduced, and pressure is released.
Optionally, in an embodiment of the present application, the buffer layer includes three periods of the first aluminum nitride layer 23 and the second aluminum nitride layer 24, that is, the buffer layer includes three first aluminum nitride layers 23 and three second aluminum nitride layers 24, and the plurality of first aluminum nitride layers 23 and the plurality of second aluminum nitride layers 24 are alternately arranged. However, the present application is not limited thereto, as the case may be.
On the basis of the above embodiment, in an embodiment of the present application, the growth temperature of the first aluminum nitride layer 23 is lower than the growth temperature of the second aluminum nitride layer 24. Specifically, in one embodiment of the present application, the first aluminum nitride layer is a low-temperature aluminum nitride layer, and the growth temperature ranges from 1020 ℃ to 1130 ℃, inclusive; the second aluminum nitride layer is a high-temperature aluminum nitride layer, and the growth temperature of the second aluminum nitride layer ranges from 1200 ℃ to 1300 ℃ inclusive.
On the basis of the above embodiments, in an embodiment of the present application, the thickness of the first aluminum nitride layer 23 ranges from 100nm to 150nm, inclusive; the thickness of the second aluminum nitride layer 24 ranges from 400nm to 600nm, inclusive.
On the basis of the above embodiments, in an embodiment of the present application, the current spreading layer is an N-type AlGaN layer, and optionally, the thickness of the current spreading layer 3 is 1 μm, the doping element is Si, and the doping concentration range is 3.0 × 1018cm-3～5.0*1018cm-3Inclusive of the endpoint values; however, the present application is not limited thereto, as the case may be.
On the basis of any one of the above embodiments, in an embodiment of the present application, the multiple quantum well active layer includes quantum barrier structures and quantum well structures that are arranged in a staggered manner for 4 to 8 periods, that is, the number of the quantum barrier structures and the quantum well structures in the multiple quantum well active layer ranges from 4 to 8 inclusive, but the present application does not limit this, which is determined by the circumstances.
On the basis of the above embodiments, in an embodiment of the present application, the quantum barrier structure and the quantum well structure are AlGaN layers, and an aluminum composition in the quantum well structure is smaller than an aluminum composition in the quantum barrier structure. Optionally, the quantum barrier structure is an N-type doped AlGaN layer, the doping element is Si, and the doping concentration value range is 3.0 × 1018cm-3～5.0*1018cm-3The thickness range of the quantum barrier structure is 10 nm-12 nm,including end point values; the quantum well structure is an undoped AlGaN layer, and the thickness range of the quantum well structure is 2 nm-3 nm, including the end point value; however, the present application is not limited thereto, as the case may be.
Referring to fig. 2, on the basis of the above embodiment, in an embodiment of the present application, the quantum barrier structure 41 includes:
the first quantum barrier layer 411 is positioned on one side, away from the buffer layer 2, of the current spreading layer 3;
a second quantum barrier layer 412 on a side of the first quantum barrier layer 411 facing away from the current spreading layer 3;
a third quantum barrier layer 413 on a side of the second quantum barrier layer 412 facing away from the first quantum barrier layer 411;
and the aluminum component in the second quantum barrier layer is larger than the aluminum components in the first quantum barrier layer and the third quantum barrier layer, so that the barrier height of the second quantum barrier layer is larger than the barrier height of the first quantum barrier layer and the third quantum barrier layer.
It should be noted that, in an embodiment of the present application, the current spreading layer is in contact with the quantum barrier structure in the multiple quantum well active layer, so as to provide recombination electrons to the quantum barrier structure by using the current spreading layer, and improve the concentration of the recombination electrons in the multiple quantum well active layer in the ultraviolet LED.
In the embodiment of the application, the barrier height of the second quantum barrier layer is greater than that of the first quantum barrier layer and that of the third quantum barrier layer, so that the effect of electron blocking is enhanced by the second quantum barrier layer with a higher barrier height, the leakage of electrons is reduced, meanwhile, the stress between the quantum barrier structure and the quantum well structure is reduced by the first quantum barrier layer and the third quantum barrier layer with a lower barrier height, the polarization electric field in the multiple quantum well active layer is weakened, the energy band bending in the multiple quantum well active layer is reduced, the wave function overlapping of electrons and holes in the multiple quantum well active layer is increased, the radiation recombination rate of the multiple quantum well active layer is further improved, and the light emitting power of the ultraviolet LED is improved.
On the basis of the above-mentioned embodiment, in an embodiment of this application, in each quantum barrier structure in M quantum barrier structures the aluminium composition in the second quantum barrier layer is the same, in other embodiments of this application, in each quantum barrier structure in M quantum barrier structures the aluminium composition in the second quantum barrier layer also can not be the same, and this application does not do the restriction to this, only needs to guarantee in the quantum barrier structure the aluminium composition in the second quantum barrier layer is greater than the aluminium composition in first quantum barrier layer with the third quantum barrier layer, so that the aluminium composition is the echelonment in the quantum barrier structure can.
The quantum barrier structure with the higher Al component can block electron leakage and further transmission of holes to the quantum well structure, so that the effect of improving the luminous power of the ultraviolet LED is limited, and a strong polarization field formed by the quantum barrier with the higher Al component is not beneficial to radiation recombination of electrons and holes, so that the further improvement of the internal quantum efficiency is limited. Compared with a quantum barrier structure with a fixed aluminum component, the quantum barrier structure with the stepped aluminum component can adopt a smaller aluminum component, so that a better electron blocking effect is realized, electron leakage is reduced, moreover, the polarization electric field can be further weakened by the smaller aluminum component, the energy band bending is slowed down, hole injection is increased, the radiation recombination rate of electrons and holes in the quantum well structure is increased, and the luminous power of the ultraviolet LED is improved.
On the basis of the above embodiments, in an embodiment of the present application, with continued reference to fig. 2, the aluminum composition in the second quantum layer in each of the M quantum barrier structures is the same. In another embodiment of the present application, as shown in fig. 3, the aluminum composition in the second quantum barrier layer in each of the M quantum barrier structures increases or decreases in a first direction, where the first direction is directed from the current spreading layer to the superlattice electron blocking layer, that is, the first direction is a growth direction of each constituent structure in the LED, such as the growth directions shown in fig. 2 and 3.
It should be noted that, in this embodiment of the application, the increasing or decreasing amplitude of the aluminum component of the second quantum barrier adjacent to each quantum barrier in each quantum barrier structure of the M quantum barrier structures may be the same or different, for example, the aluminum component of the second quantum barrier layer in the first quantum barrier structure and the aluminum component difference in the second quantum barrier layer in the second quantum barrier structure may be the same or different from the aluminum component of the second quantum barrier layer in the second quantum barrier structure and the aluminum component difference in the second quantum barrier layer in the third quantum structure.
On the basis of the above embodiments, in one embodiment of the present application, the aluminum composition in the quantum well structure is smaller than the aluminum composition in the quantum barrier structure, that is, the aluminum composition in the quantum well structure is smaller than the minimum value of the aluminum composition in the quantum barrier structure, that is, the aluminum composition in the quantum well structure is smaller than the aluminum compositions of the first quantum barrier layer and the third quantum barrier layer in the quantum barrier structure, so that the multiple quantum well active layer forms a light emitting structure.
On the basis of the above embodiments, in an embodiment of the present application, the aluminum composition in the current spreading layer is smaller than the aluminum composition in the multiple quantum well active layer, that is, the aluminum composition in the current spreading layer is smaller than the minimum value of the aluminum composition in the multiple quantum well active layer, that is, the aluminum composition in the current spreading layer is smaller than the aluminum composition in the quantum well structure, so as to reduce the stress between the current spreading layer and the subsequently grown quantum barrier structure, and provide a good foundation for the subsequently grown structure by using the current spreading layer, thereby ensuring the growth quality of the LED.
On the basis of the above embodiment, in an embodiment of the present application, the superlattice electron blocking layer is in contact with the quantum barrier structure in the multiple quantum well active layer, and the aluminum component in the third quantum barrier layer is small, so that the barrier height of the valence band hole blocking layer can be reduced, which is beneficial to the transmission of holes to the quantum well structure, thereby increasing the radiation recombination rate of electrons and holes in the quantum well structure, improving the internal quantum efficiency, and thus making the high-power ultraviolet LED prepared.
On the basis of the above embodiments, in an embodiment of the present application, the superlattice electron blocking layer is a P-type AlGaN layer, and the doping concentration ranges from 5 × 1018-10*1018The growth period of the P-type AlGaN layer ranges from 5 to 20 inclusive; however, the present application is not limited thereto, as the case may be.
With continuing reference to fig. 1, based on the above-described embodiment, in one embodiment of the present application, the ultraviolet LED further comprises:
the P-type gallium nitride layer 6 is positioned on one side, away from the multi-quantum well active layer 4, of the superlattice electron blocking layer 5, and optionally, the thickness of the P-type gallium nitride layer is 150 nm; the doping concentration value range of the P-type gallium nitride layer is 5 multiplied by 1018cm-3～10x1018cm-3The end points are included, but the application is not limited thereto, as the case may be.
On the basis of the above embodiments, in an embodiment of the present application, the ultraviolet LED further includes:
the P-type electrode 7 is positioned on one side of the P-type gallium nitride layer 6, which is far away from the superlattice electron barrier layer 5, and is electrically connected with the P-type gallium nitride layer 6;
and the N-type electrode 8 is positioned on the side, facing away from the substrate 1, of the current spreading layer 3 and is electrically connected with the current spreading layer 3.
Optionally, the P-type electrode and the N-type electrode are metal electrodes to improve the electrical performance of the ultraviolet LED, but the present application does not limit this, and is specifically determined as the case may be.
To sum up, the ultraviolet LED provided in the embodiment of the present application, the multiple quantum well active layer includes M quantum barrier structures and N quantum well structures, M is a positive integer greater than 1, N is a positive integer greater than 1, wherein the quantum barrier structure includes a first quantum barrier layer, a second quantum barrier layer and a third quantum barrier layer, an Al component of the second quantum barrier layer is higher than an Al component of the first quantum barrier layer and the third quantum barrier layer, so that the Al component in the quantum barrier structure is in a step shape, the second quantum barrier layer with a higher barrier height formed by a high Al component realizes a stronger electron blocking effect, and the first quantum barrier layer and the third quantum barrier layer with a lower barrier height formed by a low Al component simultaneously reduce stress between the quantum barrier structure and the quantum well structure, weaken a polarization electric field in the multiple quantum well active layer, reducing band bending in the multiple quantum well active layer, increasing wave function overlapping of electrons and holes in the multiple quantum well active layer, further improving radiation recombination rate of the multiple quantum well active layer, and improving luminous power of the ultraviolet LED.
Correspondingly, the embodiment of the application also provides a preparation method of the ultraviolet LED, which is used for manufacturing the ultraviolet LED provided by any one of the embodiments. Optionally, in an embodiment of the present application, the ultraviolet LED is prepared by MOCVD, and during the preparation process, trimethyl gallium TMGa, trimethyl aluminum TMAl, and ammonia NH are added3Respectively Ga source, Al source, N source, H2As carrier gas, the N-type and P-type doping sources are respectively SiH4And metallocene magnesium CP2Mg, but this is not limited to this, as the case may be.
The following description is given in conjunction with specific embodiments.
Specifically, referring to fig. 4, a method for manufacturing an ultraviolet LED provided in the embodiment of the present application includes:
s401: forming a buffer layer on the first surface of the substrate, wherein the substrate is optionally a sapphire substrate, such as a C-plane sapphire substrate, but the present application is not limited thereto, as the case may be.
On the basis of the above embodiments, in an embodiment of the present application, the buffer layer is an undoped AlN layer, and a thickness of the buffer layer ranges from 2.2 μm to 2.5 μm, inclusive, but the present application does not limit this, which is determined as the case may be.
Specifically, referring to fig. 5, in one embodiment of the present application, forming the buffer layer 2 on the first surface of the substrate 1 includes:
forming a nucleation layer 21 on a first surface of the substrate 1;
forming a recrystallization layer 22 on a side of the nucleation layer 21 facing away from the substrate;
alternately forming a plurality of first aluminum nitride layers 23 and a plurality of second aluminum nitride layers 24 on the side of the recrystallization layer 22 away from the nucleation layer, wherein the growth temperatures of the first aluminum nitride layers 23 and the second aluminum nitride layers 24 are different, and optionally, the growth temperature of the first aluminum nitride layers 23 ranges from 1020 ℃ to 1130 ℃, inclusive; the growth temperature of the second aluminum nitride layer 24 ranges from 1200 ℃ to 1300 ℃, inclusive. However, the present application is not limited thereto, as the case may be.
Based on the above embodiments, in one embodiment of the present application, the nucleation layer has a thickness of 10nm to 50nm, inclusive; the thickness of the recrystallization layer ranges from 300nm to 400nm, inclusive; the thickness of the first aluminum nitride layer ranges from 100nm to 150nm, inclusive; the thickness of the second aluminum nitride layer ranges from 400nm to 600nm, inclusive. However, the present application is not limited thereto, as the case may be.
Optionally, on the basis of the foregoing example, in an embodiment of the present application, before forming the buffer layer on the first surface of the substrate, the method further includes: and H, carrying out H treatment on the substrate to remove impurities such as oxide on the surface of the substrate.
On the basis of the above embodiments, in an embodiment of the present application, the preparation source of the buffer layer includes: TMAl and NH3. Specifically, in one embodiment of the present application, forming a nucleation layer on a first surface of the substrate includes:
placing the sapphire substrate into an MOCVD reaction chamber, and introducing high-purity hydrogen H when the temperature in the MOCVD reaction chamber reaches 1100 DEG C2Continuously turning on for 5 minutes, and carrying out H formation on the substrate;
reducing the temperature of the MOCVD reaction chamber to be within the range of 900-1000 ℃ inclusive, introducing an Al source and an N source, and forming undoped AlN on the first surface of the substrateA nucleation layer, optionally, TMAl source and N source3The thickness of the AlN low-temperature nucleating layer ranges from 10nm to 50nm inclusive;
raising the temperature of the MOCVD reaction chamber to be within the range of 1100-1200 ℃ inclusive, and keeping the temperature for 4-6 minutes to recrystallize the AlN low-temperature nucleating layer to form a recrystallized layer, wherein optionally, the thickness of the recrystallized layer ranges from 300nm to 400nm inclusive;
first aluminum nitride layers 23 and second aluminum nitride layers 24 are alternately formed on the side of the recrystallization layer 22 facing away from the nucleation layer 21, wherein the first aluminum nitride layers 23 and the second aluminum nitride layers 24 have different growth temperatures.
Specifically, on the basis of the above embodiment, in an embodiment of the present application, the alternating formation of the first aluminum nitride layer 23 and the second aluminum nitride layer 24 on the side of the recrystallization layer 22 facing away from the nucleation layer 21 includes: alternately forming a first aluminum nitride layer 23 and a second aluminum nitride layer 24 in three periods on the side of the recrystallization layer 22 away from the nucleation layer 21, wherein the growth temperature of the first aluminum nitride layer 23 ranges from 1020 ℃ to 1130 ℃ inclusive, the V/III ratio ranges from 2000 to 2500 (i.e., the molar flow ratio of the nitrogen component to the aluminum component ranges from 2000 to 2500) inclusive, and the thickness ranges from 100nm to 150nm inclusive; the growth temperature of the second aluminum nitride layer 23 ranges from 1200 ℃ to 1300 ℃, inclusive, the thickness ranges from 400nm to 600nm, inclusive, and the V/III ratio ranges from 100to 300, (i.e., the molar flow ratio of the nitrogen component to the aluminum component ranges from 100to 300), inclusive, but this is not limited in this application and is specifically determined as the case may be.
On the basis of any one of the above embodiments, in an embodiment of the present application, the thickness of the buffer layer ranges from 2.2 μm to 2.5 μm, so as to obtain a high-quality AlN layer, slow down lattice mismatch between the sapphire substrate and the subsequently grown AlGaN layer, reduce dislocation, and release stress.
S402: referring to fig. 6, a current spreading layer 3 is formed on the buffer layer 2 on the side facing away from the substrate 1.
On the basis of the above embodiments, in an embodiment of the present application, the current spreading layer is an N-type AlGaN layer, the doping element is Si, and the doping concentration range is 3.0 × 1018cm-3～5.0*1018cm-3The thickness of the current spreading layer 3 is 1 μm, inclusive, but this is not limited in this application, as the case may be.
On the basis of the above embodiment, in an embodiment of the present application, a current spreading layer 3 is formed on a side of the buffer layer 2 facing away from the substrate 1, and a preparation source of the current spreading layer includes: TMAl, NH3TMGa and SiH as dopant4Wherein a molar flow ratio of the group v element component (i.e., nitrogen component)/the group iii element component (i.e., sum of aluminum component and gallium component) in the current spreading layer ranges from 950 to 1050 inclusive, which is not limited in the present application.
Specifically, in an embodiment of the present application, forming the current spreading layer 3 on the side of the buffer layer 2 away from the substrate 1 includes:
introducing a Ga source and silane on the basis of introducing an Al source and an N source into the MOCVD reaction chamber, and growing an N-type AlGaN layer on one side of the buffer layer 2, which is far away from the substrate 1, in the temperature range of 1000-1200 ℃ to be used as a current expansion layer 3.
S403: and forming a multi-quantum well active layer on one side of the current expansion layer, which is far away from the buffer layer, wherein the multi-quantum well active layer comprises M quantum barrier structures and N quantum well structures, M is a positive integer larger than 1, and N is a positive integer larger than 1, and the quantum barrier structures and the quantum well structures are arranged in a staggered mode.
It should be noted that, in an embodiment of the present application, the aluminum composition in the current spreading layer is smaller than the aluminum composition in the multiple quantum well active layer, that is, the aluminum composition in the current spreading layer is smaller than the minimum value of the aluminum composition in the multiple quantum well active layer, that is, the aluminum composition in the current spreading layer is smaller than the aluminum composition in the quantum well structure and smaller than the aluminum composition in the quantum barrier structure, so as to reduce the stress between the current spreading layer and the subsequently grown quantum barrier structure, and provide a good foundation for the subsequently grown structure by using the current spreading layer, thereby ensuring the growth quality of the crystal.
Referring to fig. 7, on the basis of the above embodiment, in an embodiment of the present application, forming a multiple quantum well active layer 4 on a side of the current spreading layer 3 facing away from the buffer layer 2 includes: quantum barrier structures 41 and quantum well structures 42 are alternately formed on the side of the current spreading layer 3 away from the buffer layer 2, so that M quantum barrier structures and N quantum well structures are formed on the side of the current spreading layer away from the buffer layer. Specifically, in an embodiment of the present application, in a process of alternately forming a quantum barrier structure and a quantum well structure on a side of the current spreading layer 3 away from the buffer layer 2, a source for preparing the quantum barrier structure and the quantum well structure includes: TMAl, NH3TMGa and dopant SiH4However, the present application is not limited thereto, and the details may be determined as appropriate.
On the basis of the above embodiments, in an embodiment of the present application, the materials of the quantum barrier structure and the quantum well structure are AlGaN materials, and the aluminum composition in the quantum well structure is smaller than that in the quantum barrier structure. The thickness range of the quantum barrier structure is 10 nm-12 nm, including the end point value; the thickness of the quantum well structure ranges from 2nm to 3nm, inclusive, but the application does not limit this, as the case may be. The thickness L of the quantum barrier structure is the sum of the thicknesses of the first quantum barrier layer L1, the second quantum barrier layer L2 and the third quantum barrier layer L3, namely L is L1+ L2+ L3.
It should be noted that, in an embodiment of the present application, the current spreading layer is in contact with the quantum barrier structure in the multiple quantum well active layer, so as to provide recombination electrons to the quantum barrier structure by using the current spreading layer, and improve the concentration of the recombination electrons in the multiple quantum well active layer in the ultraviolet LED.
It should be further noted that, in the embodiment of the present application, the number M of the quantum barrier structures is 1 more than the number N of the quantum well structures, so that the subsequently formed superlattice electron blocking layer is in contact with the quantum barrier structures in the multiple quantum well active layer, and the aluminum component in the third quantum barrier layer is smaller, thereby reducing the barrier height of the valence band hole blocking layer, facilitating the transmission of holes to the quantum well structures, further increasing the radiative recombination rate of electrons and holes in the quantum well structures, and improving the internal quantum efficiency, thereby enabling the high power ultraviolet LEDs to be manufactured.
On the basis of the above embodiments, in an embodiment of the present application, the method for forming the quantum barrier structure 41 includes: adjusting the temperature of the MOCVD reaction chamber to 1100 ℃, and introducing an Al source, a Ga source, an N source and silane to start growing AlyGa1-yN layer to form a stepped quantum barrier structure with a doping concentration of 3.0 x 1018cm-3～5.0*1018cm-3Inclusive of the endpoint values; specifically, in an embodiment of the present application, the method for forming the quantum barrier structure 41 includes:
s401: under a first rotating speed and a first pressure, a first quantum barrier layer 411 is grown by using an aluminum source with a first flow rate, and the first quantum barrier layer 411 is positioned on one side, away from the buffer layer 2, of the current spreading layer 3;
s402: increasing the flow rate of the aluminum source to a second flow rate, and growing a second quantum barrier layer 412 by using the second flow rate of the aluminum source, wherein the second quantum barrier layer 412 is located on the side, away from the current spreading layer 3, of the first quantum barrier layer 411;
s403: and reducing the flow rate of the aluminum source to a third flow rate, and growing a third quantum barrier layer 413 by using the aluminum source with the third flow rate, wherein the third quantum barrier layer 413 is located on the side, away from the first quantum barrier layer 411, of the second quantum barrier layer 412.
In the embodiment of the present application, the second flow rate is greater than the first flow rate and the third flow rate, so that the aluminum composition of the second quantum barrier layer 412 is greater than the aluminum composition of the first quantum barrier layer 411 and the third quantum barrier layer 413.
It should be noted that in the embodiment of the present application, during the process of preparing the quantum barrier structure, an aluminum component is adjusted by controlling a flow rate of trimethylaluminum (TMAl), so that the aluminum component of the second quantum barrier layer is greater than the aluminum components of the first quantum barrier layer and the third quantum barrier layer, and the quantum barrier structure forms a step shape.
The quantum barrier structure with the higher Al component can block electron leakage and further transmission of holes to the quantum well structure, so that the effect of improving the luminous efficiency of the ultraviolet LED is limited, and the strong polarization field formed by the quantum barrier with the higher Al component is not beneficial to radiation recombination of electrons and holes, so that the further improvement of the internal quantum efficiency of the ultraviolet LED can be limited. Compared with a quantum barrier structure with a fixed aluminum component, the quantum barrier structure with the stepped aluminum component can adopt a smaller aluminum component, so that a better electron blocking effect is realized, electron leakage is reduced, moreover, the polarization electric field can be further weakened by the smaller aluminum component, the energy band bending is slowed down, hole injection is increased, the radiation recombination rate of electrons and holes in the quantum well structure is increased, and the luminous power of the ultraviolet LED is improved.
Optionally, in an embodiment of the present application, a growth temperature of the quantum barrier structure ranges from 1050 ℃ to 1150 ℃, inclusive, and growth time of the first quantum barrier layer, the second quantum barrier layer, and the third quantum barrier layer ranges from 30s to 60s, inclusive, but the present application does not limit this, which is determined as the case may be.
On the basis of any one of the above embodiments, in an embodiment of the present application, the quantum barrier structure is prepared by using a low pressure and a low rotation speed to improve the crystal quality of the quantum barrier structure, and optionally, the value range of the first pressure is 100torr to 200torr, including an end point value; the first rotation speed ranges from 200rpm to 300rpm, inclusive.
Specifically, on the basis of the above embodiments, in an embodiment of the present application, the growing the second quantum barrier layer by using the aluminum source at the second flow rate includes:
step 4021: introducing an aluminum source with a second flow rate in a first time period;
step 4022: stopping introducing the aluminum source in a second time period;
and repeating the step 4021 and the step 4022 until the growth of the second quantum barrier layer is completed.
In the embodiment of the application, the second quantum barrier layer is formed by a pulse aluminum-feeding method, that is, when trimethylaluminum (TMAl) is fed in the growth process of the second quantum barrier layer, trimethylaluminum (TMAl) is fed in the first time period, trimethylaluminum (TMAl) is not fed in the second time period, and the second quantum barrier layer is grown by circulating the first time period and the second time period, so that a steeper interface can be obtained by the growth method, and TMAl and NH can be reduced3The two-dimensional mode growth of the second quantum barrier layer is enhanced, and therefore the second quantum barrier layer with good crystal quality and small stress is obtained.
On the basis of the above embodiment, in an embodiment of the present application, a value range of the first time period is 3s to 10s, including an endpoint value; the value range of the second time period is 3s to 10s, including an endpoint value, in other embodiments of the application, the value ranges of the first time period and the second time period may also be 1s to 5s, 2s to 8s, 3s to 9s, and the like, but the application does not limit this, which is determined as the case may be.
It should be noted that, in the above embodiment, the value ranges of the first time period and the second time period may be the same or different, and the application does not limit this, and only needs to ensure that the aluminum source at the second flow rate is introduced in the first time period, and the introduction of the aluminum source at the second flow rate is stopped in the second time period.
On the basis of any one of the above embodiments, in an embodiment of the present application, a method for forming the quantum well includes: growing a quantum well structure on the surface of the quantum barrier structure at a second rotating speed and a second pressure, wherein the quantum well structure is undoped AlxGa1-xN layer, and the second rotation speed is greater than the first rotation speed, the second pressure is greater than the first pressure, so that the growth of the quantum barrier structure adopts a phaseThe method has lower pressure and rotation speed on the quantum well structure, thereby increasing the migration rate of Al atoms on the surface of the quantum barrier structure, simultaneously being beneficial to the incorporation of Al components, providing a foundation for growing the high-quality quantum well structure and obtaining better crystal quality.
On the basis of any one of the above embodiments, in an embodiment of the present application, a method for forming the quantum well structure includes:
on the basis of introducing an Al source, an N source, a Ga source and silane into the MOCVD reaction chamber, adjusting the pressure in the MOCVD reaction chamber and the rotating speed of the turntable to be under the conditions of a second rotating speed and a second pressure within the temperature value range of 1050-1150 ℃;
depositing undoped Al on the side of the quantum barrier structure away from the current spreading layer by using a fourth flow of aluminum sourcexGa1-xAnd the N layer is used as a quantum well structure.
Optionally, the fourth flow rate is smaller than the first flow rate, the second flow rate, and the third flow rate, so that the aluminum composition in the quantum well structure is smaller than the aluminum composition in the quantum barrier structure.
On the basis of the above embodiment, in an embodiment of the present application, the value range of the second pressure is 200torr to 300torr, including an endpoint value; the second rotation speed ranges from 300rpm to 600rpm, inclusive, but the present application does not limit this, as the case may be.
On the basis of the above embodiments, in an embodiment of the present application, the multiple quantum well active layer includes quantum barrier structures and quantum well structures that are arranged in a staggered manner for 4 to 8 periods, that is, the number of the quantum barrier structures and the quantum well structures in the multiple quantum well active layer ranges from 4 to 8 inclusive, but the present application does not limit this, which is determined by the specific circumstances.
On the basis of the above-mentioned embodiment, in an embodiment of this application, in each quantum barrier structure in M quantum barrier structures the aluminium composition in the second quantum barrier layer is the same, in other embodiments of this application, in each quantum barrier structure in M quantum barrier structures the aluminium composition in the second quantum barrier layer also can not be the same, and this application does not do the restriction to this, only needs to guarantee in the quantum barrier structure the aluminium composition in the second quantum barrier layer is greater than the aluminium composition in first quantum barrier layer with the third quantum barrier layer, so that the aluminium composition is the echelonment in the quantum barrier structure can.
Specifically, if the aluminum component in the second quantum barrier layer in each of the M quantum barrier structures is different, the aluminum component in the second quantum barrier layer in each of the M quantum barrier structures may be increased in magnitude along the first direction, or may be decreased in magnitude along the first direction. The current spreading layer points to the superlattice electron blocking layer in the first direction, namely the first direction is a growth direction of each component structure in the LED.
It should be noted that, in this embodiment of the application, the increasing or decreasing amplitude of the aluminum component in the adjacent second quantum barrier layer in each quantum barrier structure of the M quantum barrier structures may be the same or different, for example, the aluminum component of the second quantum barrier layer in the first quantum barrier structure and the aluminum component difference in the second quantum barrier layer in the second quantum barrier structure may be the same or different from the aluminum component of the second quantum barrier layer in the second quantum barrier structure and the aluminum component difference in the second quantum barrier layer in the third quantum barrier structure.
S404: referring to fig. 8, a superlattice electron blocking layer 5 is formed on a side of the multiple quantum well active layer 4 away from the current spreading layer 3, so that electron overflow in the multiple quantum well active layer is reduced by using the superlattice electron blocking layer, and the light emitting efficiency of the LED chip is improved.
On the basis of the above embodiments, in an embodiment of the present application, the superlattice electron blocking layer is a P-type doped AlGaN layer, and the doping concentration ranges from 5 × 1018-10*1018Including the endpoint values ofThe growth period of the superlattice electron blocking layer ranges from 5 to 20 inclusive, but the growth period is not limited in this application and is determined as the case may be.
On the basis of the above embodiment, in an embodiment of the present application, when the superlattice electron blocking layer 5 is formed on the side of the multiple quantum well active layer 4 away from the current spreading layer 3, the preparation source of the superlattice electron blocking layer includes: TMAl, NH3TMGa and P type dopant is CP2Mg, but this is not limited to this, as the case may be.
Specifically, on the basis of the above embodiment, in an embodiment of the present application, the forming of the superlattice electron blocking layer on the side of the multiple quantum well active layer away from the current spreading layer includes:
adjusting the temperature of the MOCVD reaction chamber to 1150 ℃, introducing a CP (carbon plasma) on the basis of introducing an Al source, an N source and a Ga source into the MOCVD reaction chamber2And Mg, depositing a P-type doped AlGaN layer on one side of the multi-quantum well active layer, which is far away from the current expansion layer, so as to form a superlattice electron blocking layer.
Referring to fig. 9, on the basis of the above embodiment, in an embodiment of the present application, the preparation method further includes:
and a P-type gallium nitride layer 6 is formed on the side of the superlattice electron blocking layer 5, which is far away from the multiple quantum well active layer 4, and is used as a contact layer. Optionally, the thickness of the P-type gallium nitride layer is 150nm, and the value range of the P-type doping concentration in the P-type gallium nitride layer is 5.0 × 1018cm-3～10.0*1018cm-3The present application is not limited to the above-mentioned values, which are included as the end points, as the case may be;
by means of an annealing furnace (e.g. a flash annealing furnace) in N2And annealing the P-type gallium nitride layer in the atmosphere, wherein the annealing temperature is selected from 850-900 ℃ inclusive, and the annealing time is selected from 20-30 min inclusive.
It should be noted that, in the embodiment of the present application, the pressure of the reaction chamber during the whole growth process of the ultraviolet LED ranges from 100torr to 300torr, inclusive.
On the basis of the above embodiment, in an embodiment of the present application, the preparation method further includes:
referring to fig. 10, a first region of the P-type gallium nitride layer 6, the superlattice electron blocking layer 5 and the multiple quantum well active layer 4 is etched to expose the current spreading layer 3, wherein the first region is used for forming an N-type electrode 8 subsequently;
referring to fig. 11, a P-type electrode 7 electrically connected to the P-type gallium nitride layer 6 is formed on the side of the P-type gallium nitride layer 6 away from the superlattice electron blocking layer 5; an N-type electrode 8 electrically connected with the current spreading layer 3 is formed on the side of the current spreading layer 3 away from the substrate 1.
Optionally, the P-type electrode and the N-type electrode are metal electrodes to improve the electrical performance of the ultraviolet LED, but the present application does not limit this, and is specifically determined as the case may be.
In summary, in the method for manufacturing the ultraviolet LED provided in the embodiment of the present application, the multiple quantum well active layer includes M quantum barrier structures and N quantum well structures, M is a positive integer greater than 1, and N is a positive integer greater than 1, wherein the quantum barrier structures include a first quantum barrier layer, a second quantum barrier layer, and a third quantum barrier layer, an Al component of the second quantum barrier layer is higher than Al components of the first quantum barrier layer and the third quantum barrier layer, so that the Al component in the quantum barrier structure presents a step shape, so as to realize a stronger electron blocking effect by using the second quantum barrier layer with a higher barrier height formed by a high Al component, and simultaneously, the stress between the quantum barrier structure and the quantum well structure is reduced by using the first quantum barrier layer with a lower barrier height formed by a low Al component and the third quantum barrier layer, thereby weakening a polarization electric field in the multiple quantum well active layer, reducing band bending in the multiple quantum well active layer, increasing wave function overlapping of electrons and holes in the multiple quantum well active layer, further improving radiation recombination rate of the multiple quantum well active layer, and improving luminous power of the ultraviolet LED.
In the description, each part is described in a progressive manner, each part is emphasized to be different from other parts, and the same and similar parts among the parts are referred to each other.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (16)

1. An ultraviolet LED, comprising:
a substrate;
a buffer layer on the first surface of the substrate;
the current expansion layer is positioned on one side, away from the substrate, of the buffer layer;
the multiple quantum well active layer is positioned on one side, away from the buffer layer, of the current expansion layer and comprises M quantum barrier structures and N quantum well structures, M is a positive integer larger than 1, N is a positive integer larger than 1, and the quantum barrier structures and the quantum well structures are arranged in a staggered mode;
the superlattice electron blocking layer is positioned on one side, away from the current spreading layer, of the multi-quantum well active layer;
the quantum barrier structure comprises a first quantum barrier layer, a second quantum barrier layer and a third quantum barrier layer, wherein the Al component of the second quantum barrier layer is higher than the Al components of the first quantum barrier layer and the third quantum barrier layer.
2. The ultraviolet LED of claim 1, wherein the current spreading layer is in contact with a quantum barrier structure in the multiple quantum well active layer.
3. The uv LED of claim 1, wherein said superlattice electron blocking layer is in contact with a quantum barrier structure in said multiple quantum well active layer.
4. The uv LED of claim 1, wherein the aluminum composition in the second quantum barrier layer is the same for each of the M quantum barrier structures.
5. The UV LED of claim 4, wherein the aluminum composition in the second quantum barrier layer in each of the M quantum barrier structures increases or decreases in a first direction from the current spreading layer to the superlattice electron blocking layer.
6. The ultraviolet LED of claim 1, wherein the aluminum composition in the quantum well structure is less than the aluminum composition in the quantum barrier structure.
7. The ultraviolet LED of claim 1, wherein the aluminum composition in the current spreading layer is less than the aluminum composition in the multiple quantum well active layer.
8. The UV LED of any one of claims 1-7, wherein the doping concentration of the N-type dopant in the quantum barrier structure is in the range of 3 x 1018cm-3～5x1018cm-3Inclusive.
9. The ultraviolet LED of claim 1, wherein the quantum barrier structure has a thickness ranging from 10nm to 12nm, inclusive; the thickness of the quantum well structure ranges from 2nm to 3nm, inclusive.
10. A preparation method of an ultraviolet LED is characterized by comprising the following steps:
step 1: forming a buffer layer on a first surface of a substrate;
step 2: forming a current spreading layer on one side of the buffer layer, which is far away from the substrate;
and step 3: forming a multi-quantum well active layer on one side, away from the buffer layer, of the current spreading layer, wherein the multi-quantum well active layer comprises M quantum barrier structures and N quantum well structures, M is a positive integer larger than 1, and N is a positive integer larger than 1, and the quantum barrier structures and the quantum well structures are arranged in a staggered mode;
and 4, step 4: forming a superlattice electron blocking layer on one side, away from the current spreading layer, of the multi-quantum well active layer;
the quantum barrier structure comprises a first quantum barrier layer, a second quantum barrier layer and a third quantum barrier layer, wherein the Al component of the second quantum barrier layer is higher than the Al components of the first quantum barrier layer and the third quantum barrier layer.
11. The manufacturing method according to claim 10, wherein a multiple quantum well active layer is formed on a side of the current spreading layer facing away from the buffer layer, the multiple quantum well active layer includes M quantum barrier structures and N quantum well structures, M is a positive integer greater than 1, and N is a positive integer greater than 1, wherein the staggered arrangement of the quantum barrier structures and the quantum well structures includes:
and alternately forming quantum barrier structures and quantum well structures on the side, away from the buffer layer, of the current spreading layer so as to form M quantum barrier structures and N quantum well structures on the side, away from the buffer layer, of the current spreading layer, wherein M is greater than N by 1.
12. The method of claim 11, wherein the forming of the quantum barrier structure comprises:
step 401: growing a first quantum barrier layer by using an aluminum source with a first flow rate at a first rotating speed and a first pressure;
step 402: increasing the flow of the aluminum source to a second flow, and growing a second quantum barrier layer by using the aluminum source with the second flow;
step 403: and reducing the flow of the aluminum source to a third flow, and growing a third quantum barrier layer by using the aluminum source with the third flow.
13. The method of claim 12, wherein growing the second quantum barrier layer using the second flow rate of the aluminum source comprises:
step 4011: introducing an aluminum source with a second flow rate in a first time period;
step 4012: stopping introducing the aluminum source in a second time period;
and repeating the step 4011 and the step 4012 until the growth of the second quantum barrier layer is completed.
14. The method of claim 13, wherein the first time period ranges from 3s to 10s, inclusive; the value range of the second time period is 3 s-10 s, including the endpoint value.
15. The method of claim 12, wherein the first pressure ranges from 100torr to 200torr, inclusive; the first rotation speed ranges from 200rpm to 300rpm, inclusive.
16. The method of manufacturing according to claim 12, wherein the method of forming the quantum well structure comprises:
and growing a quantum well structure on the surface of the quantum barrier structure at a second rotating speed and a second pressure, wherein the second rotating speed is greater than the first rotating speed, and the second pressure is greater than the first pressure.
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116469981A (en) * 2023-06-09 2023-07-21 江西兆驰半导体有限公司 High-luminous-efficiency light-emitting diode and preparation method thereof
CN116995160A (en) * 2023-07-31 2023-11-03 广东技术师范大学 AlGaN-based deep ultraviolet light-emitting diode

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102299223A (en) * 2011-09-19 2011-12-28 厦门乾照光电股份有限公司 Epitaxial structure of light-emitting diode and manufacturing method thereof
CN103247728A (en) * 2013-05-09 2013-08-14 青岛杰生电气有限公司 Semiconductor ultraviolet source device
CN105304770A (en) * 2015-09-21 2016-02-03 东莞市中镓半导体科技有限公司 Preparation method for near ultraviolet (NUV) LED containing Al component and thickness stepwise gradient type quantum barrier structure
CN108110104A (en) * 2018-01-18 2018-06-01 厦门乾照光电股份有限公司 A kind of light emitting diode and preparation method thereof
CN109300852A (en) * 2018-09-03 2019-02-01 淮安澳洋顺昌光电技术有限公司 A kind of luminance raising LED luminescent layer epitaxial structure and preparation method thereof
CN109616559A (en) * 2018-12-04 2019-04-12 深圳市洲明科技股份有限公司 A kind of AlGaN base ultraviolet LED epitaxial slice structure and preparation method thereof
CN109950371A (en) * 2019-03-13 2019-06-28 深圳市洲明科技股份有限公司 Ultraviolet LED epitaxial structure and preparation method thereof
CN109950368A (en) * 2019-02-18 2019-06-28 华灿光电(苏州）有限公司 Gallium nitride based LED epitaxial slice and its manufacturing method
CN110098294A (en) * 2019-05-05 2019-08-06 深圳市洲明科技股份有限公司 The ultraviolet LED epitaxial structure and preparation method thereof of structure is built with novel quantum

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102299223A (en) * 2011-09-19 2011-12-28 厦门乾照光电股份有限公司 Epitaxial structure of light-emitting diode and manufacturing method thereof
CN103247728A (en) * 2013-05-09 2013-08-14 青岛杰生电气有限公司 Semiconductor ultraviolet source device
CN105304770A (en) * 2015-09-21 2016-02-03 东莞市中镓半导体科技有限公司 Preparation method for near ultraviolet (NUV) LED containing Al component and thickness stepwise gradient type quantum barrier structure
CN108110104A (en) * 2018-01-18 2018-06-01 厦门乾照光电股份有限公司 A kind of light emitting diode and preparation method thereof
CN109300852A (en) * 2018-09-03 2019-02-01 淮安澳洋顺昌光电技术有限公司 A kind of luminance raising LED luminescent layer epitaxial structure and preparation method thereof
CN109616559A (en) * 2018-12-04 2019-04-12 深圳市洲明科技股份有限公司 A kind of AlGaN base ultraviolet LED epitaxial slice structure and preparation method thereof
CN109950368A (en) * 2019-02-18 2019-06-28 华灿光电(苏州）有限公司 Gallium nitride based LED epitaxial slice and its manufacturing method
CN109950371A (en) * 2019-03-13 2019-06-28 深圳市洲明科技股份有限公司 Ultraviolet LED epitaxial structure and preparation method thereof
CN110098294A (en) * 2019-05-05 2019-08-06 深圳市洲明科技股份有限公司 The ultraviolet LED epitaxial structure and preparation method thereof of structure is built with novel quantum

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CN116469981A (en) * 2023-06-09 2023-07-21 江西兆驰半导体有限公司 High-luminous-efficiency light-emitting diode and preparation method thereof
CN116995160A (en) * 2023-07-31 2023-11-03 广东技术师范大学 AlGaN-based deep ultraviolet light-emitting diode
CN116995160B (en) * 2023-07-31 2024-04-19 广东技术师范大学 AlGaN-based deep ultraviolet light-emitting diode

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