CN112397622A - Light emitting diode epitaxial wafer and preparation method thereof - Google Patents

Light emitting diode epitaxial wafer and preparation method thereof Download PDF

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CN112397622A
CN112397622A CN202110072179.1A CN202110072179A CN112397622A CN 112397622 A CN112397622 A CN 112397622A CN 202110072179 A CN202110072179 A CN 202110072179A CN 112397622 A CN112397622 A CN 112397622A
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layer
gan
sublayer
emitting diode
island
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CN112397622B (en
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洪威威
王倩
梅劲
董彬忠
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HC Semitek Zhejiang Co Ltd
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HC Semitek Zhejiang 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
    • H01L33/12—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 stress relaxation structure, e.g. buffer layer
    • 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
    • H01L33/0075—Processes for devices with an active region comprising only III-V compounds 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
    • H01L33/04—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
    • H01L33/02—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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Abstract

The invention discloses a light-emitting diode epitaxial wafer and a preparation method thereof, belonging to the field of light-emitting diode manufacturing. The buffer layer comprises a first sub-layer and a second sub-layer, and the first sub-layer plays a transition role. The second sub-layer stacked on the first sub-layer comprises the second GaN layer and the BGaN layer which are stacked alternately, on one hand, lattice mismatch is relieved, a good foundation is provided for the growth of a subsequent epitaxial structure, the BGaN layer can be inserted or filled in a blank position caused by dislocation due to the fact that the size of B atoms is small, defects in the buffer layer are reduced, the B atoms can play a certain positioning role, dislocation is prevented from continuously moving to the n-type GaN layer and the multi-quantum well layer, and the crystal quality of the finally obtained light emitting diode epitaxial wafer is effectively improved.

Description

Light emitting diode epitaxial wafer and preparation method thereof
Technical Field
The invention relates to the field of light emitting diode manufacturing, in particular to a light emitting diode epitaxial wafer and a preparation method thereof.
Background
A light emitting diode is a semiconductor electronic component that can emit light. As a novel high-efficiency, environment-friendly and green solid-state illumination light source, the solid-state illumination light source is rapidly and widely applied, such as traffic signal lamps, automobile interior and exterior lamps, urban landscape illumination, mobile phone backlight sources and the like, and the aim of improving the light emitting efficiency of a chip is continuously pursued by light emitting diodes.
The light emitting diode epitaxial wafer is a basic structure for preparing a light emitting diode, and generally comprises a substrate, and an AlN layer, a GaN buffer layer, an n-type GaN layer, a multi-quantum well layer and a p-type GaN layer which are sequentially grown on the substrate. The GaN buffer layer can relieve lattice mismatch between the n-type GaN layer and the substrate to a certain extent so as to improve the crystal quality of the multiple quantum well layer and the p-type GaN layer grown on the n-type GaN layer and the n-type GaN layer.
However, when the GaN buffer layer itself grows on the AlN layer, some dislocation defects are accumulated, and these dislocation defects extend into the structure of the n-type GaN layer or the like, resulting in limited improvement in the crystal quality of the finally obtained n-type GaN layer, multi-quantum well layer, and p-type GaN layer.
Disclosure of Invention
The embodiment of the invention provides a light-emitting diode epitaxial wafer and a preparation method thereof, which can reduce the defects in the light-emitting diode epitaxial wafer so as to improve the crystal quality of the finally obtained light-emitting diode epitaxial wafer. The technical scheme is as follows:
the embodiment of the invention provides a light-emitting diode epitaxial wafer, which comprises a substrate, and an AlN layer, a buffer layer, an n-type GaN layer, a multi-quantum well layer and a p-type GaN layer which are sequentially laminated on the substrate,
the buffer layer comprises a first sublayer and a second sublayer, wherein the first sublayer and the second sublayer are sequentially stacked on the AlN layer, the first sublayer is a first GaN layer, and the second sublayer comprises a second GaN layer and a BGaN layer which are alternately stacked.
Optionally, a ratio of a thickness of the first sublayer to a thickness of the second sublayer is 1: 10-1: 1.
Optionally, the thickness of the first sub-layer is 30-100 nm, and the thickness of the second sub-layer is 30-200 nm.
Optionally, the thickness of the second GaN layer is 20nm to 150nm, and the thickness of the BGaN layer is 10nm to 50 nm.
The embodiment of the disclosure provides a preparation method of a light emitting diode epitaxial wafer, which comprises the following steps:
providing a substrate;
growing an AlN layer on the substrate;
growing a buffer layer on the AlN layer, wherein the buffer layer comprises a first sublayer and a second sublayer which are sequentially laminated on the AlN layer, the first sublayer is a first GaN layer, and the second sublayer comprises a second GaN layer and a BGaN layer which are alternately laminated;
and sequentially growing an n-type GaN layer, a multi-quantum well layer and a p-type GaN layer on the buffer layer.
Optionally, growing a buffer layer on the AlN layer, comprising:
growing a plurality of GaN island-shaped structures distributed at intervals on the AlN layer in a pure nitrogen atmosphere;
growing a GaN material on the GaN island-shaped structures under an atmosphere environment in which pure nitrogen atmosphere and pure hydrogen atmosphere are alternately switched until a plurality of GaN island-shaped structures grow and are combined to form a first sublayer;
a second sublayer is grown on the first sublayer.
Optionally, a Ga source with the flow rate of 200 sccm-500 sccm is introduced into the reaction cavity, ammonia gas with the flow rate of 50 sccm-150 sccm is introduced into the reaction cavity, and nitrogen gas with the flow rate of 100 sccm-200 sccm is introduced into the reaction cavity, so that a plurality of GaN island-shaped structures distributed at intervals grow on the AlN layer.
Optionally, the growth time of the GaN island-shaped structure is 100-600 s.
Optionally, in the process of growing and merging the plurality of GaN island-shaped structures to form the first sublayer, a ratio of a time length of the plurality of GaN island-shaped structures growing in a pure nitrogen atmosphere to a time length of the plurality of GaN island-shaped structures growing in a pure hydrogen atmosphere is 3:1 to 1: 1.
Optionally, during the growth and combination of the plurality of GaN island-shaped structures to form the first sub-layer,
when the plurality of GaN island-shaped structures grow in the pure nitrogen atmosphere, the used carrier gas is nitrogen;
when the plurality of GaN island-shaped structures grow in a pure hydrogen atmosphere, the used carrier gas is hydrogen.
The technical scheme provided by the embodiment of the invention has the following beneficial effects:
in the light emitting diode epitaxial wafer, the buffer layer between the AlN layer and the n-type GaN layer is arranged to comprise a first sublayer and a second sublayer, the first sublayer of the first GaN layer is used as a foundation for transition, lattice mismatch between the AlN layer and the first sublayer is relieved, and the AlN layer can be well transited to the second sublayer and the n-type GaN layer. The second sub-layer stacked on the first sub-layer comprises a second GaN layer and a BGaN layer which are alternately stacked, so that on one hand, stress can be effectively released, and defects can be reduced; on the other hand, the lattice mismatch between the second GaN layer and the first GaN layer is small, the lattice mismatch between the AlN layer and the n-type GaN layer can be further relieved, a good foundation is provided for the growth of a subsequent epitaxial structure, the blank position caused by dislocation can be inserted or filled in the BGaN layer due to the small volume of the B atoms, the defects in the buffer layer are reduced, the B atoms can play a certain positioning role, the dislocation is prevented from continuously moving to the n-type GaN layer and the multi-quantum well layer, and the crystal quality of the finally obtained light emitting diode epitaxial wafer is effectively improved.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic structural diagram of an led epitaxial wafer according to an embodiment of the present disclosure;
fig. 2 is a schematic structural diagram of another light emitting diode epitaxial wafer according to an embodiment of the present disclosure;
fig. 3 is a flowchart of a method for manufacturing an epitaxial wafer of a light emitting diode according to an embodiment of the present invention;
fig. 4 is a flowchart of another method for manufacturing an epitaxial wafer of a light emitting diode according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
Fig. 1 is a schematic structural diagram of a light emitting diode epitaxial wafer according to an embodiment of the present disclosure, and as can be seen from fig. 1, the embodiment of the present disclosure provides a light emitting diode epitaxial wafer including a substrate 1, and an AlN layer 2, a buffer layer 3, an n-type GaN layer 4, a multi-quantum well layer 5, and a p-type GaN layer 6 sequentially stacked on the substrate 1.
The buffer layer 3 includes a first sublayer 31 and a second sublayer 32 sequentially stacked on the AlN layer 2, the first sublayer 31 being a first GaN layer, and the second sublayer 32 including a second GaN layer 321 and a BGaN layer 322 alternately stacked.
In the light emitting diode epitaxial wafer, the buffer layer 3 between the AlN layer 2 and the n-type GaN layer 4 is configured to include a first sublayer 31 and a second sublayer 32, the first sublayer 31 of the first GaN layer is used as a base transition, lattice mismatch between the AlN layer 2 and the first sublayer 31 is relieved, and the AlN layer 2 can be well transited to the second sublayer 32 and the n-type GaN layer 4. The second sub-layer 32 stacked on the first sub-layer 31 includes the second GaN layer 321 and the BGaN layer 322 stacked alternately, which can effectively release stress and reduce defects on one hand; on the other hand, the lattice mismatch between the second GaN layer 321 and the first GaN layer is small, so that the lattice mismatch between the AlN layer 2 and the n-type GaN layer 4 can be further alleviated, and a good foundation is provided for the growth of a subsequent epitaxial structure, while the BGaN layer 322 can be inserted or filled in a blank position caused by dislocation due to the small volume of B atoms, so that defects existing inside the buffer layer 3 are reduced, and the B atoms can play a certain role in positioning, so that the dislocation is prevented from continuously moving into the n-type GaN layer 4 and the multiple quantum well layer 5, and the crystal quality of the finally obtained light emitting diode epitaxial wafer is effectively improved.
It should be noted that the improvement of the crystal quality of the multiple quantum well layer 5 can reduce the internal defects of the multiple quantum well layer 5 to reduce the probability that carriers will generate non-radiative recombination in the multiple quantum well layer 5, increase the probability of radiative recombination of carriers, and increase the light emitting intensity of the light emitting diode.
Illustratively, the thickness of the first sub-layer 31 is 30-100 nm, and the thickness of the second sub-layer 32 is 30-200 nm.
When the thickness of the first sublayer 31 and the thickness of the second sublayer 32 are within the above ranges, the quality of the buffer layer 3 itself to be finally obtained is good, and the quality of the n-type GaN layer 4 grown on the buffer layer 3 is good.
Optionally, the ratio of the thickness of the first sublayer 31 to the thickness of the second sublayer 32 is 1: 10-1: 1.
When the ratio of the thickness of the first sublayer 31 to the thickness of the second sublayer 32 is within the above range, the first sublayer 31 itself has better growth quality, the quality of the second sublayer 32 grown on the first sublayer 31 is also better, meanwhile, the second sublayer 32 itself can block more defects, and the quality of the finally obtained buffer layer 3 and the n-type GaN layer 4 grown on the buffer layer 3 can be effectively improved.
Illustratively, the thickness of the second GaN layer 321 is 20nm to 150nm, and the thickness of the BGaN layer 322 is 10nm to 50 nm.
When the thickness of the second GaN layer 321 and the thickness of the BGaN layer 322 are in the above range, the stress in the buffer layer 3 can be effectively released. And the second GaN layer 321 can realize good transition, the BGaN layer 322 can also block more defects, and the quality of the finally obtained buffer layer 3 can be greatly improved.
Optionally, the number of layers of the second GaN layer 321 and the BGaN layer 322 may be the same, and the number of layers of the second GaN layer 321 and the BGaN layer 322 is 4-20.
When the number of the second GaN layer 321 and the number of the BGaN layer 322 are the same and both are within the above range, the second sublayer 32 with better quality can be obtained, so that the quality of the n-type GaN layer 4 grown on the second sublayer 32 can be improved.
Fig. 2 is a schematic structural diagram of another light emitting diode epitaxial wafer according to an embodiment of the present disclosure, and as can be seen from fig. 2, in another implementation manner provided by the present disclosure, the light emitting diode epitaxial wafer may include a substrate 1, and an AlN layer 2, a buffer layer 3, an undoped GaN layer 7, an n-type GaN layer 4, a multi-quantum well layer 5, an AlGaN electron blocking layer 8, a p-type GaN layer 6, and a p-type contact layer 9 grown on the substrate 1.
It should be noted that the buffer layer 3 shown in fig. 2 has the same structure as the buffer layer 3 shown in fig. 1, and the details are not repeated here.
Alternatively, the substrate 1 may be a sapphire substrate 1. Easy to manufacture and obtain.
Illustratively, the AlN layer 2 may have a thickness of 10 to 50 nm. And can play a certain role in relieving lattice mismatch.
Illustratively, the thickness of the undoped GaN layer 7 may be 0.5 to 3 μm. The quality of the obtained light emitting diode epitaxial wafer is good.
In one implementation provided by the present disclosure, the thickness of the undoped GaN layer 7 may also be 1 μm. The present disclosure is not so limited.
Alternatively, the doping element of the n-type GaN layer 4 may be Si, and the doping concentration of the Si element may be 1 × 1018~ 1×1019cm-3. The overall quality of the n-type GaN layer 4 is good.
Illustratively, the thickness of the n-type GaN layer 4 may be 0.5 to 3 μm. The obtained n-type GaN layer 4 has good quality as a whole.
In one implementation provided by the present disclosure, the thickness of the n-type GaN layer 4 may be 2 μm. The present disclosure is not so limited.
Illustratively, the MQW layer 5 includes a plurality of InGaN well layers 51 and GaN barrier layers 52 alternately stacked, the thickness of the InGaN well layers 51 may be 2-5 nm, and the thickness of the GaN barrier layers 52 may be 8-20 nm.
The number of layers of the InGaN well layer 51 and the number of layers of the GaN barrier layer 52 can be 8-15. The obtained multiple quantum well layer 5 has a good structure.
Optionally, the Al content of the AlGaN electron blocking layer 8 may be 0.15 to 0.25. The effect of blocking electrons is better.
Optionally, the thickness of the AlGaN electron blocking layer 8 can be 20-100 nm. The obtained AlGaN electron blocking layer 8 has good quality.
Enough cavities can be provided, and the overall cost of the light-emitting diode epitaxial wafer is not too high.
Optionally, the p-type GaN layer 6 can be doped with Mg, and the thickness of the p-type GaN layer 6 can be 100-200 nm.
Illustratively, the thickness of the p-type contact layer 9 may be 10 to 50 nm.
Note that, in the epitaxial wafer structure shown in fig. 2, in comparison with the epitaxial wafer structure shown in fig. 1, an AlGaN electron blocking layer 8 for preventing electron overflow is added between the multiple quantum well layer 5 and the p-type GaN layer 6, and a p-type contact layer 9 is also grown on the p-type GaN layer 6. The obtained epitaxial wafer has better quality and luminous efficiency.
Fig. 3 is a flowchart of a method for manufacturing an led epitaxial wafer according to an embodiment of the present disclosure, and as shown in fig. 3, the method for manufacturing an led epitaxial wafer includes:
s101: a substrate is provided.
S102: an AlN layer is grown on the substrate.
S103: and growing a buffer layer on the AlN layer, wherein the buffer layer comprises a first sublayer and a second sublayer which are sequentially laminated on the AlN layer, the first sublayer is a first GaN layer, and the second sublayer comprises a second GaN layer and a BGaN layer which are alternately laminated.
S104: and sequentially growing an n-type GaN layer, a multi-quantum well layer and a p-type GaN layer on the buffer layer.
The technical effect of the method shown in fig. 3 can refer to the technical effect of the light emitting diode epitaxial wafer shown in fig. 1, and therefore, the technical effect of the method shown in fig. 3 is not described again here. The led epitaxial wafer structure after the step S104 is executed can refer to fig. 1.
Fig. 4 is a flowchart of another method for manufacturing an led epitaxial wafer according to an embodiment of the present disclosure, and as shown in fig. 4, the method for manufacturing an led epitaxial wafer includes:
s201: a substrate is provided.
Wherein the substrate may be a sapphire substrate. Easy to realize and manufacture.
Illustratively, the substrate may be 2 inches, 4 inches, or 6 inches in size. Easy preparation and acquisition.
Optionally, step S201 may further include: and treating the surface of the substrate for growing the epitaxial layer for 5-6 min in a hydrogen atmosphere.
For example, when the substrate is processed for growing the surface of the epitaxial layer, the temperature of the reaction chamber may be 1000 to 1100 ℃, and the pressure of the reaction chamber may be 200 to 500 Torr.
S202: an AlN layer is grown on the substrate.
The AlN layer may be obtained by magnetron sputtering.
Illustratively, the deposition temperature of the AlN layer may be 400 to 800 ℃, the sputtering power may be 3000 to 5000W, and the pressure may be 2 to 20 mtorr. The obtained AlN layer has good quality.
S203: a buffer layer is grown on the AlN layer.
Step S203 may include: growing a plurality of GaN island-shaped structures distributed at intervals on the AlN layer in a pure nitrogen atmosphere; growing a GaN material on the GaN island-shaped structures under an atmosphere environment in which pure nitrogen atmosphere and pure hydrogen atmosphere are alternately switched until the plurality of GaN island-shaped structures grow and are combined to form a first sublayer; a second sublayer is grown on the first sublayer.
The nitrogen has a large physical viscosity coefficient, so that a single GaN island-shaped structure can adsorb an organic metal source and reaction gas to longitudinally grow in the process of forming the GaN island-shaped structure, the GaN island-shaped structures with large volume, high thickness and no excessive number can be formed on the AlN layer, and when the GaN island-shaped structures finally grow and are combined into a first sublayer, the defects generated by combination are few, so that the defects which can exist in the first sublayer finally can be reduced, and the overall crystal quality of the buffer layer is improved. In the process of continuously growing the GaN island-shaped structure, the atmosphere environment in the reaction cavity is alternately switched between the pure nitrogen atmosphere and the pure hydrogen atmosphere, the physical property viscosity coefficient of hydrogen is small, the organic metal source and the reaction gas can more easily move and expand transversely in the pure hydrogen atmosphere, and transverse expansion and combination of the GaN island-shaped structure are realized. The pure nitrogen atmosphere and the pure hydrogen atmosphere are alternately switched, so that the volume of the GaN island-shaped structure can be effectively increased in the process of finally realizing the transverse expansion of the GaN island-shaped structure, the merging time of the GaN island-shaped structure is delayed, the volume of the GaN island-shaped structure is increased, and the defects generated by merging are reduced. And the merging time is relatively late, and the stress accumulated in the growth process of the GaN island-shaped structure can be effectively released during the final merging, so that the crystal quality of the first sublayer is improved.
It should be noted that the pure hydrogen atmosphere or pure hydrogen atmosphere provided in the present disclosure refers to the atmosphere of the reaction chamber before the organometallic source and the reaction gas are introduced.
In step S203, the pure nitrogen atmosphere and the pure hydrogen atmosphere in the reaction chamber can be achieved by continuously introducing the same kind of gas into the reaction chamber and replacing the original gas environment in the reaction chamber. Generally, 5-20 s of nitrogen is introduced into the reaction cavity or 5-20 s of hydrogen is introduced into the reaction cavity, so that the reaction cavity can be kept in a pure nitrogen atmosphere or a pure hydrogen atmosphere.
In step S203, a Ga source with a flow rate of 200 sccm-500 sccm can be introduced into the reaction chamber, ammonia gas with a flow rate of 50 sccm-150 sccm can be introduced into the reaction chamber, and nitrogen gas with a flow rate of 100 sccm-200 sccm can be introduced into the reaction chamber, so that a plurality of GaN island-shaped structures distributed at intervals can be grown on the AlN layer.
The Ga source, the ammonia gas and the nitrogen gas with the flow rates can be introduced to obtain a GaN island-shaped structure with good quality, and the nitrogen gas can also play a role of adsorbing an organic metal source in the growth process of the GaN island-shaped structure due to the large flow rate of the introduced nitrogen gas, so that the formation of the GaN island-shaped structure is promoted, and the growth efficiency of the GaN island-shaped structure is improved.
Optionally, a Ga source with the flow rate of 200 sccm-500 sccm and the time duration of 100 s-600 s can be introduced into the reaction cavity, ammonia gas with the flow rate of 50 sccm-150 sccm can be introduced into the reaction cavity, and nitrogen gas with the flow rate of 100 sccm-200 sccm can be introduced into the reaction cavity, so that a plurality of GaN island-shaped structures distributed at intervals can be grown on the AlN layer.
The forming time of the GaN island-shaped structure is in the range, the height of the obtained GaN island-shaped structure is proper, and the GaN island-shaped structure can continue to grow and be combined into a first sublayer with moderate thickness and good quality in the subsequent process.
In the step S203, in the process of growing and merging the plurality of GaN island-shaped structures to form the first sublayer, the ratio of the time length of the plurality of GaN island-shaped structures growing in the pure nitrogen atmosphere to the time length of the plurality of GaN island-shaped structures growing in the pure hydrogen atmosphere is 3: 1-1: 1.
The ratio of the growth time of the GaN island-shaped structures in the pure nitrogen atmosphere to the growth time of the plurality of GaN island-shaped structures in the pure hydrogen atmosphere is in the above range, so that the GaN island-shaped structures can uniformly and stably grow transversely and longitudinally, and the finally obtained first sub-layer has good quality.
It is to be noted that when the GaN island structure grows in a pure nitrogen atmosphere, the materials introduced into the reaction chamber are Ga source, nitrogen and ammonia; when the GaN island-shaped structure grows in the pure hydrogen atmosphere, the materials introduced into the reaction cavity are a Ga source, hydrogen and ammonia.
Optionally, the duration of each time that the GaN island-shaped structure is carried out in a pure nitrogen atmosphere can be 10 s-200 s, and the duration of each time that the GaN island-shaped structure is carried out in a pure hydrogen atmosphere can be 10 s-200 s. The quality and uniformity of the finally obtained first sub-layer are good.
Exemplarily, in a pure nitrogen atmosphere, introducing a Ga source with the flow rate of 200 sccm-500 sccm into the reaction cavity, introducing ammonia gas with the flow rate of 50 sccm-150 sccm into the reaction cavity, introducing nitrogen gas with the flow rate of 100 sccm-200 sccm into the reaction cavity, and depositing a GaN material on the GaN island-shaped structure; and introducing a Ga source with the flow rate of 200 sccm-500 sccm into the reaction cavity, introducing ammonia gas with the flow rate of 50 sccm-150 sccm into the reaction cavity, introducing hydrogen gas with the flow rate of 100 sccm-300 sccm into the reaction cavity, and depositing a GaN material on the GaN island-shaped structure.
The first sublayer with better quality can be obtained by adopting the arrangement in the previous section, and the defects remained in the first sublayer are less.
Step S203 may further include turning off the Ga source, the nitrogen gas, and the ammonia gas, and switching the pure nitrogen atmosphere to the pure hydrogen atmosphere, or turning off the Ga source, the hydrogen gas, and the ammonia gas, and switching the pure hydrogen atmosphere to the pure nitrogen atmosphere.
In the process of switching the atmosphere, the Ga source is not introduced for growth, and only nitrogen or hydrogen which needs to be switched is introduced. The process is close to annealing treatment, and can release stress accumulated by growth of the GaN island-shaped structure to a certain extent, so that the crystal quality of the finally obtained buffer layer is improved.
Optionally, in the process of growing and merging the plurality of GaN island-shaped structures to form the first sublayer, when the plurality of GaN island-shaped structures grow in a pure nitrogen atmosphere, the used carrier gas is nitrogen; when the plurality of GaN island-shaped structures grow in a pure hydrogen atmosphere, the used carrier gas is hydrogen. The purity of the gas environment in the reaction cavity can be ensured, so that the stable deposition and growth of the GaN material can be ensured.
It should be noted that, in the process of growing and merging the plurality of GaN island-shaped structures to form the first sub-layer, the nitrogen and hydrogen introduced into the reaction chamber are additionally introduced materials, rather than the result caused by introducing the carrier gas itself. The flow rate of the carrier gas is usually 20 sccm-50 sccm, and the influence on the growth of the light-emitting diode epitaxial wafer is almost negligible.
Optionally, in the process of growing and combining the plurality of GaN island-shaped structures to form the first sublayer, the number of times of switching the pure hydrogen atmosphere and the pure nitrogen atmosphere is 2-10 times. The quality of the first sublayer obtained finally is better.
In step S203, growing a second sub-layer on the first sub-layer may include: and alternately growing a second GaN layer and a BGaN layer, and finally forming a second sublayer on the first sublayer. The growth temperature of the second GaN layer is 1000-1100 ℃, and the growth pressure of the second GaN layer is 100-300 Torr. The growth temperature of the BGaN layer is 900-1100 ℃, and the growth pressure of the BGaN layer is 100-300 Torr.
S204: and growing an undoped GaN layer on the buffer layer.
The thickness of the non-doped GaN layer can be 0.5-3 um.
Illustratively, the growth temperature of the non-doped GaN layer can be 1000-1100 ℃, and the growth pressure is controlled at 100-300 Torr. The obtained undoped GaN layer has better quality.
S205: and growing an n-type GaN layer on the undoped GaN layer.
Alternatively, the growth temperature of the n-type GaN layer may be 1000 to 1100 ℃, and the growth pressure of the n-type GaN layer may be 100 to 300 Torr.
S206: and growing a multi-quantum well layer on the n-type GaN layer.
The multiple quantum well layer comprises InGaN well layers and GaN barrier layers which are alternately stacked, the thickness of each InGaN well layer can be 2-3 nm, and the thickness of each GaN barrier layer can be 9-20 nm.
Optionally, in the multiple quantum well layer, the growth temperature of the InGaN well layer and the growth temperature of the InGaN well layer may be 700 to 830 ℃, and the growth temperature of the GaN barrier layer, and the growth temperature of the third GaN barrier layer may be 800 to 960 ℃. The quality of the multiple quantum well layer grown under the condition is good, and the light emitting efficiency of the light emitting diode can be ensured.
S207: and growing an AlGaN electronic barrier layer on the multi-quantum well layer.
The growth temperature of the AlGaN electron blocking layer can be 800-1000 ℃, and the growth pressure of the AlGaN electron blocking layer can be 100-300 Torr. The AlGaN electron blocking layer grown under the condition has good quality, and is beneficial to improving the luminous efficiency of the light-emitting diode.
S208: and growing a p-type GaN layer on the AlGaN electron blocking layer.
Alternatively, the growth pressure of the p-type GaN layer may be 200 to 600Torr, and the growth temperature of the p-type GaN layer may be 800 to 1000 ℃.
S209: and growing a p-type contact layer on the p-type GaN layer.
Alternatively, the growth pressure of the p-type contact layer may be 100 to 300Torr, and the growth temperature of the p-type contact layer may be 800 to 1000 ℃.
The method for manufacturing the light emitting diode epitaxial wafer shown in fig. 4 provides a more detailed method for growing the light emitting diode epitaxial wafer compared to the method for manufacturing the light emitting diode shown in fig. 3.
The structure of the light emitting diode epitaxial wafer after the step S209 is performed can be seen in fig. 2.
It should be noted that, in the embodiment of the present disclosure, a Veeco K465i or C4 or RB MOCVD (Metal Organic Chemical Vapor Deposition) apparatus is adopted to implement the growth method of the light emitting diode. By using high-purity H2(Hydrogen) or high purity N2(Nitrogen) or high purity H2And high purity N2Mixed gas ofAs carrier gas, high purity NH3As an N source, trimethyl gallium (TMGa) and triethyl gallium (TEGa) as gallium sources, trimethyl indium (TMIn) as indium sources, silane (SiH 4) as an N-type dopant, trimethyl aluminum (TMAl) as an aluminum source, and magnesium dicylocene (CP)2Mg) as a P-type dopant.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims (10)

1. A light emitting diode epitaxial wafer comprises a substrate, and an AlN layer, a buffer layer, an n-type GaN layer, a multi-quantum well layer and a p-type GaN layer which are sequentially laminated on the substrate,
the buffer layer comprises a first sublayer and a second sublayer, wherein the first sublayer and the second sublayer are sequentially stacked on the AlN layer, the first sublayer is a first GaN layer, and the second sublayer comprises a second GaN layer and a BGaN layer which are alternately stacked.
2. The light-emitting diode epitaxial wafer according to claim 1, wherein the ratio of the thickness of the first sub-layer to the thickness of the second sub-layer is 1:10 to 1: 1.
3. The light-emitting diode epitaxial wafer according to claim 1, wherein the thickness of the first sub-layer is 30-100 nm, and the thickness of the second sub-layer is 30-200 nm.
4. The light-emitting diode epitaxial wafer according to any one of claims 1 to 3, wherein the thickness of the second GaN layer is 20nm to 150nm, and the thickness of the BGaN layer is 10nm to 50 nm.
5. A preparation method of a light emitting diode epitaxial wafer is characterized by comprising the following steps:
providing a substrate;
growing an AlN layer on the substrate;
growing a buffer layer on the AlN layer, wherein the buffer layer comprises a first sublayer and a second sublayer which are sequentially laminated on the AlN layer, the first sublayer is a first GaN layer, and the second sublayer comprises a second GaN layer and a BGaN layer which are alternately laminated;
and sequentially growing an n-type GaN layer, a multi-quantum well layer and a p-type GaN layer on the buffer layer.
6. The production method according to claim 5, wherein growing a buffer layer on the AlN layer comprises:
growing a plurality of GaN island-shaped structures distributed at intervals on the AlN layer in a pure nitrogen atmosphere;
growing a GaN material on the GaN island-shaped structures under an atmosphere environment in which pure nitrogen atmosphere and pure hydrogen atmosphere are alternately switched until a plurality of GaN island-shaped structures grow and are combined to form a first sublayer;
a second sublayer is grown on the first sublayer.
7. The method as claimed in claim 6, wherein a Ga source with a flow rate of 200sccm to 500sccm is introduced into the reaction chamber, an ammonia gas with a flow rate of 50sccm to 150sccm is introduced into the reaction chamber, and a nitrogen gas with a flow rate of 100sccm to 200sccm is introduced into the reaction chamber, so as to grow a plurality of GaN island-shaped structures distributed at intervals on the AlN layer.
8. The method according to claim 7, wherein the growth time of the GaN island-like structure is 100s to 600 s.
9. The method according to any one of claims 6 to 8, wherein during the growth and combination of the plurality of GaN island-shaped structures to form the first sub-layer, a ratio of a time period during which the plurality of GaN island-shaped structures are grown in a pure nitrogen atmosphere to a time period during which the plurality of GaN island-shaped structures are grown in a pure hydrogen atmosphere is 3:1 to 1: 1.
10. The production method according to any one of claims 6 to 8, wherein during the growth and combination of the plurality of GaN island-like structures to form the first sub-layer,
when the plurality of GaN island-shaped structures grow in the pure nitrogen atmosphere, the used carrier gas is nitrogen;
when the plurality of GaN island-shaped structures grow in a pure hydrogen atmosphere, the used carrier gas is hydrogen.
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CN115692556A (en) * 2023-01-03 2023-02-03 江西兆驰半导体有限公司 Three-dimensional GaN layer, preparation method and light emitting diode epitaxial wafer

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