CN114628557A - LED epitaxial structure, preparation method thereof and LED device - Google Patents

LED epitaxial structure, preparation method thereof and LED device Download PDF

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CN114628557A
CN114628557A CN202011454243.4A CN202011454243A CN114628557A CN 114628557 A CN114628557 A CN 114628557A CN 202011454243 A CN202011454243 A CN 202011454243A CN 114628557 A CN114628557 A CN 114628557A
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epitaxial structure
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不公告发明人
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Focus Lightings Technology Suqian Co ltd
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Focus Lightings Technology Suqian 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
    • H01L33/14—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
    • 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
    • H01L33/04—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
    • H01L33/26—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 invention provides an LED epitaxial structure, a preparation method thereof and an LED device, wherein the LED epitaxial structure sequentially comprises a substrate, a non-doped semiconductor layer, an N-type semiconductor layer, a multi-quantum well region and a P-type semiconductor layer from bottom to top; the multi-quantum well region comprises a plurality of potential well layer groups and barrier layers which are alternately stacked, and a plurality of In-doped potential well layers with In doping concentration gradually reduced from bottom to top are stacked In each potential well layer group. The possibility of introducing structural defects such as dislocation, stacking fault, V-shaped defect, pore and the like due to stress mismatch In the epitaxial layer caused by In segregation is reduced, so that the lattice quality is enhanced; and potential energy difference at two ends of the quantum well is increased, the recombination efficiency of electrons and holes is increased, and the luminous efficiency is further improved.

Description

LED epitaxial structure, preparation method thereof and LED device
Technical Field
The invention relates to the field of semiconductor light-emitting devices, in particular to an LED epitaxial structure, a preparation method thereof and an LED device.
Background
Light Emitting Diodes (LEDs), especially nitride LEDs, have been widely used in the field of general lighting because of their high Light Emitting efficiency.
At present, In components In a GaN-based blue light LED quantum well are high, In segregation is easily caused, and structural defects such as dislocation, stacking fault, V-shaped defect and pore are introduced due to mismatch stress In an epitaxial layer with high In doping concentration, so that the crystal quality is deteriorated, and the luminous efficiency is reduced; moreover, as the light emitting layer becomes thicker, the polarization effect In the GaN material system is increased due to the increase of the In component, and the energy band distortion and the potential energy decrease are caused by the larger polarization effect, so that the effective recombination region of electrons and holes is reduced, and the light emitting efficiency is further reduced.
Disclosure of Invention
The invention aims to provide an LED epitaxial structure, a preparation method thereof and an LED device.
The invention provides an LED epitaxial structure, which sequentially comprises a substrate, a non-doped semiconductor layer, an N-type semiconductor layer, a multi-quantum well region and a P-type semiconductor layer from bottom to top, and further comprises at least one group of electron enrichment layer groups arranged below the multi-quantum well region, wherein multiple In-doped electron enrichment layers with sequentially increasing In-doped concentration from bottom to top are stacked In each group of electron enrichment layer groups;
the multi-quantum well region comprises a plurality of potential well layer groups and barrier layers which are alternately stacked, and a plurality of In-doped potential well layers with In-doped concentrations decreasing from bottom to top are stacked In each potential well layer group.
As a further improvement of the invention, the number of the electron enrichment layer groups is 3-6, and the In doping concentration of the electron enrichment layer cyclically and periodically changes among a plurality of groups of the electron enrichment layer groups.
As a further improvement of the invention, 2-4 electron enrichment layers are arranged In each group of electron enrichment layer group, and the electron enrichment layers are InaGa(1-a)N, wherein a is more than 0.1 and less than 0.3.
As a further improvement of the invention, 3-10 pairs of the potential well layer group and the barrier layer which are alternately stacked are arranged in the multi-quantum well region.
As a further improvement of the invention, 3-8 layers of potential well layers are arranged in each group of potential well layer groups,the well layer is InbGa(1-b)N, wherein b is more than 0.1 and less than 0.3.
As a further improvement of the invention, the barrier layer is AlcGa(1-c)N, wherein c is more than 0.1 and less than 0.3.
As a further improvement of the invention, an Al-doped interface transition layer is arranged between each barrier layer and the potential well layer group below the barrier layer, the Al doping concentration in the interface transition layer is higher than that in the barrier layer, and the interface transition layer is AldGa(1-d)N, wherein c is less than d and less than 0.3.
As a further improvement of the invention, an insertion layer is further arranged below each group of potential well layer groups, the forbidden bandwidth of the insertion layer is smaller than that of the potential well layer, the insertion layer is an InN layer, and the thickness range of the insertion layer is 0.5-1 nm.
The invention also provides an LED device which is characterized by comprising the LED epitaxial structure, an N electrode and a P electrode, wherein the N electrode is in ohmic contact with the N type semiconductor layer, and the P electrode is in ohmic contact with the P type semiconductor layer.
The invention also provides a preparation method of the LED epitaxial structure, which comprises the following steps:
growing a non-doped semiconductor layer and a first N-type semiconductor layer on a substrate in sequence;
growing a plurality of In-doped electron enrichment layers to form a group of electron enrichment layer groups, wherein the In doping concentration of each electron enrichment layer is increased In sequence according to the growth sequence;
growing a plurality of layers of In-doped potential well layers to form a group of potential well layer groups, wherein the In doping concentration of each potential well layer is reduced In sequence according to the growth sequence;
growing a barrier layer;
alternately and repeatedly growing the potential well layer group and the barrier layer to form a multi-quantum well region;
and growing a P-type semiconductor layer.
As a further improvement of the invention, the method also comprises the following steps:
and repeatedly growing 2-5 groups of the electron enrichment layer groups on the electron enrichment layer groups, wherein In doping concentration of the electron enrichment layer cyclically and periodically changes among the electron enrichment layer groups.
As a further improvement of the present invention, the "growing a plurality of In-doped electron-rich layers" specifically includes:
growing 2-4 layers of InaGa(1-a)And N forms a group of the electron enrichment layer group, wherein a is more than 0.1 and less than 0.3, and the In doping concentration is increased In sequence according to the growth sequence.
As a further improvement of the invention, the method also comprises the following steps after the electron enrichment layer group is grown:
growing an InN layer with the thickness ranging from 0.5 nm to 1nm to form an insertion layer.
As a further improvement of the invention, 3-8 pairs of the potential well layer group and the barrier layer are alternately grown.
As a further improvement of the present invention, the "growing a plurality of In-doped well layers" specifically includes:
growing 3-8 In layersbGa(1-b)N forms a group of potential well layer groups, wherein b is more than 0.1 and less than 0.3, and the In doping concentration is reduced In sequence according to the growth sequence.
As a further improvement of the present invention, the "growth barrier layer" specifically includes:
growing AlcGa(1-c)N forms a barrier layer, wherein 0.1 < c < 0.3.
As a further improvement of the invention, the method further comprises the following steps before the barrier layer is grown:
growing a layer of AldGa(1-d)N forms an interface transition layer, wherein c < d < 0.3.
The invention has the beneficial effects that: by arranging the electron enrichment layer with the gradually increased In doping concentration and the potential well layer with the gradually decreased In doping concentration, more electrons can be accumulated In the electron enrichment layer to provide electrons for the light emitting layer, so that the electron utilization rate is improved; secondly, the possibility of introducing structural defects such as dislocation, stacking fault, V-shaped defect, pore and the like due to stress mismatch In the epitaxial layer caused by In segregation is reduced, so that the lattice quality is enhanced; thirdly, the potential energy difference at two ends of the quantum well is increased, the recombination efficiency of electrons and holes is increased, and the luminous efficiency is further improved. And each barrier layer is also provided with an Al-doped interface transition layer, and the Al doping concentration in the interface transition layer is higher than that in the barrier layer, so that the Al-doped interface moves forwards towards the potential well layer, and the descending relation of the Al doping concentration is formed between the interface transition layer and the barrier layer, thereby further enhancing the lattice quality.
Drawings
Fig. 1 is a schematic view of an epitaxial structure of an LED according to an embodiment of the invention.
Fig. 2 is a schematic flow chart of a method for manufacturing an LED epitaxial structure according to an embodiment of the present invention.
Fig. 3 to 10 are schematic diagrams illustrating steps of a method for fabricating an LED epitaxial structure according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more clear, the technical solutions of the present application will be clearly and completely described below with reference to the detailed embodiments of the present application and the accompanying drawings. It should be apparent that the described embodiments are only some embodiments of the present application, and not all embodiments. All other embodiments obtained by a person of ordinary skill in the art without any creative effort based on the embodiments in the present application belong to the protection scope of the present application.
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.
For convenience in explanation, the description herein uses terms indicating relative spatial positions, such as "upper," "lower," "rear," "front," and the like, to describe one element or feature's relationship to another element or feature as illustrated in the figures. The term spatially relative position may encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "above" other elements or features would then be oriented "below" or "above" the other elements or features. Thus, the exemplary term "below" can encompass both a spatial orientation of below and above.
As shown in fig. 1, the present invention provides an LED epitaxial structure, which sequentially comprises a substrate 1, an undoped semiconductor layer 2, an N-type semiconductor layer 3, a multi-quantum well region 6, and a P-type semiconductor layer 7 from bottom to top.
The substrate 1 is made of sapphire, silicon carbide, silicon or a composite substrate of the materials, and can also be made of other common LED substrate materials.
The N-type semiconductor layer 3 and the P-type semiconductor layer 7 are any one of group III nitride based semiconductor layers commonly used in the art, and the present invention is not particularly limited thereto.
In some embodiments of the present invention, a nitride buffer layer is further disposed on the substrate 1 to reduce lattice mismatch between the substrate 1 and the semiconductor layer, so as to improve the growth quality of the epitaxial layer.
The LED epitaxial structure further comprises at least one group of electron enrichment layer groups 4 arranged below the multi-quantum well region 6, and a plurality of In-doped electron enrichment layers 41 with sequentially increasing In doping concentration from bottom to top are stacked In each group of electron enrichment layer groups 4.
Here, by providing the electron enrichment layer 41In which the In doping concentration is gradually increased, the In content is gradually increased, and the possibility of introducing structural defects such as dislocation, stacking fault, V-type defect, pore and the like due to stress mismatch In the epitaxial layer caused by In segregation is reduced, so that the lattice quality is enhanced, and the potential energy difference between a trap and a barrier is increased; and more electrons can be accumulated in the electron-rich layer 41 through the electron-rich layer 41 to provide electrons to the light emitting layer, thereby improving the electron utilization rate.
Furthermore, the number of the electron enrichment layer groups 4 is 3-6, and 2-4 electron enrichment layers 41 are arranged in each electron enrichment layer group 4. The In doping concentration of the electron enrichment layer 41 cyclically and periodically changes among the electron enrichment layer groups 4. The number of the electron enrichment layer groups 4 and the number of the electron enrichment layers 41In each group are limited, so that on one hand, the situation that the layers with gradually changed In concentration cannot be formed due to too few electron enrichment layers 41 and enough electron enrichment layers 41 cannot be provided for accumulating electrons is avoided, and on the other hand, the situation that the total thickness of the electron enrichment layers is too thick due to too many electron enrichment layers 41 and the polarization effect is more obvious is avoided.
Further, the electron-rich layer 41 is InaGa(1-a)N, wherein a is more than 0.1 and less than 0.3.
Specifically, in the present embodiment, there are 6 sets of electron enrichment layer groups 4, and each set of electron enrichment layer group 4 includes 3 layers of electron enrichment layers 41 from bottom to top: a first electron-rich layer 41a, a second electron-rich layer 41b, and a third electron-rich layer 41c, which are In, respectivelya1Ga(1-a1)N、Ina2Ga(1-a2)N and Ina3Ga(1-a3)N, wherein 0.1 < a1 < a2 < a3 < 0.3. In each group of electron enrichment layer groups 4, the first electron enrichment layer 41a, the second electron enrichment layer 41b, and the third electron enrichment layer 41c are sequentially and periodically stacked, that is, the electron enrichment layers 41 are formed in the order of the first electron enrichment layer 41a, the second electron enrichment layer 41b, the third electron enrichment layer 41c, the first electron enrichment layer 41a, the second electron enrichment layer 41b, and the third electron enrichment layer 41c … ….
In the present embodiment, the In doping concentration between the electron-rich layers 41 is uniformly changed within each electron-rich layer group 4. In some other embodiments, the In doping concentration may also be gradually changed according to a parabolic trend or an exponential trend, and the invention is not limited thereto, and the In doping concentration change gradient may be formed.
In some other embodiments of the present invention, a stress relief layer is further grown between the N-type semiconductor layer 3 and the electron-rich layer group 4 to reduce lattice strain and reduce the problems of cracks or dislocations caused by lattice mismatch.
The multiple quantum well region 6 includes a plurality of well layer groups 61 and barrier layers 62 stacked alternately, and In each group of well layer group 61, a plurality of In-doped well layers 611 whose In doping concentration decreases progressively from bottom to top are stacked.
The electron enrichment layer 41 with the gradually increased In concentration is arranged at first, and the potential well layer 611 with the gradually decreased In concentration is arranged on the electron enrichment layer, so that the potential energy difference at two ends of a single quantum well is increased, the recombination efficiency of electrons and holes is increased, the luminous efficiency is improved, the In component is not improved while the potential energy difference is increased, and the energy band inclination and the energy band distortion caused by the polarization effect are reduced.
Further, 3-10 pairs of potential well layer groups 61 and barrier layers 62 which are alternately stacked are arranged in the multiple quantum well region 6, and 3-8 potential well layers 611 are arranged in each group of potential well layer group 61. The number of quantum wells and the number of potential well layers 611 in each potential well layer group 61 are limited, so that on one hand, the problem that the number of layers of the multiple quantum well region 6 serving as a main light emitting region is too small, electrons and holes cannot be sufficiently compounded, and the light emitting brightness is reduced is avoided, and on the other hand, the problem that the polarization effect is more obvious due to the fact that the thickness of the multiple quantum well region 6 is too thick, dislocation is increased, the quality of crystal lattices is poor, and the light emitting efficiency is influenced is avoided.
Further, the well layer 611 is InbGa(1-b)N, wherein b is more than 0.1 and less than 0.3.
Specifically, in this embodiment, the multi-quantum well region 6 includes 10 pairs of well layer groups 61 and barrier layers 62 stacked alternately, and 3 layers of well layers 611 are provided in each well layer group 61 from bottom to top: a first well layer 611, a second well layer 611 and a third well layer 611, which are In, respectivelyb1Ga(1-ab1)N、Inb2Ga(1-b2)N and Inb3Ga(1-b3)N, wherein, 0.1 < b3 < b2 < b1 < 0.3. In each well layer group 61, the first well layer 611, the second well layer 611, and the third well layer 611 are repeatedly stacked, that is, the multiple quantum well region 6 is formed in the order of the first well layer 611, the second well layer 611, the third well layer 611, the barrier layer 62, the first well layer 611, the second well layer 611, the third well layer 611, and the barrier layer 62 … ….
In the present embodiment, the In doping concentration between the electron-rich layers 41 is uniformly changed within each group of the potential well layer group 61. In some other embodiments, the In doping concentration may also be gradually changed according to a parabolic trend or an exponential trend, and the present invention is not limited thereto specifically, and the In doping concentration change gradient may be formed.
In some other embodiments of the present invention, a layer of insertion layer 5 is further disposed below each group of well layer groups 61, and its forbidden bandwidth is smaller than that of the well layer 611.
By inserting a small-forbidden-band-width insertion layer 5 below the potential well layer group 61, the energy band inclination between the potential well layer 611 and the barrier layer 62 is reduced, and the spatial wave function overlapping amount is increased, so that the stark effect is effectively limited, and the light emitting efficiency is further increased.
Specifically, in the present embodiment, the insertion layer 5 is an InN layer, and has a thickness in the range of 0.5 to 1 nm.
In the present embodiment, the barrier layer 62 is AlcGa(1-c)N, wherein c is more than 0.1 and less than 0.3.
Further, in some other embodiments of the present invention, an interface transition layer 621 doped with Al is further disposed between each barrier layer 62 and the potential well layer group 61 below the barrier layer, and the Al doping concentration in the interface transition layer 621 is higher than the Al doping concentration in the barrier layer 62, so that, on one hand, by doping Al in the interface transition layer 621, the potential energy height of the barrier layer 62 is further increased to achieve the effect of blocking electrons; on the other hand, the Al-doped interface moves forward toward the well layer 611, and a decreasing relationship of Al doping concentration is formed between the interface transition layer 621 and the barrier layer 62, so that the problems of poor lattice quality of the barrier layer 62 caused by Al doping, energy band distortion caused by polarization effect, and the like are alleviated, thereby reducing electron overflow and increasing the light emitting efficiency.
Specifically, in this embodiment, the interface transition layer 621 is AldGa(1-d)N, wherein c is less than d and less than 0.3.
In some embodiments of the present invention, the LED epitaxial structure further includes a current blocking layer and other conventional LED epitaxial structures, which are not described herein again.
The invention also provides an LED device which comprises the LED epitaxial structure, an N electrode and a P electrode, wherein the N electrode is in ohmic contact with the N type semiconductor layer 3, and the P electrode is in ohmic contact with the P type semiconductor layer 7.
As shown in fig. 2, the present invention further provides a method for manufacturing an LED epitaxial structure, including the steps of:
s1: as shown in fig. 3, an undoped semiconductor layer 2 and a first N-type semiconductor layer 3 are sequentially grown on a substrate 1.
After being pretreated, the substrate 1 is placed into a reaction chamber of metal organic chemical vapor deposition equipment to grow the non-doped semiconductor layer 2 and the first N-type semiconductor layer 3, and in some embodiments of the present invention, a nitride buffer layer also grows on the substrate 1.
S2: as shown In fig. 4, a plurality of In-doped electron-rich layers 41 are grown to form a group of electron-rich layer groups 4, and the In doping concentration of each electron-rich layer 41 is sequentially increased In the order of growth.
In some embodiments of the invention, further comprising the step of:
as shown In fig. 5, 2-5 electron enrichment layer groups 4 are repeatedly grown on the electron enrichment layer group 4, and the In doping concentration of the electron enrichment layer 41 cyclically and periodically changes among the electron enrichment layer groups 4.
Specifically, 2 to 4 In layers are grownaGa(1-a)N forms a group of electron enrichment layer groups 4, wherein a is more than 0.1 and less than 0.3, and the In doping concentration is increased In sequence according to the growth sequence.
As shown in fig. 6, in some embodiments of the present invention, after the step of growing the electron-rich layer group 4, the method further includes the steps of:
growing an InN layer with a thickness of 0.5-1 nm to form an insertion layer 5.
Furthermore, the growth temperature of the insertion layer 5 is 5-10 ℃ lower than that of the later growth potential well layer 611.
S3: as shown In fig. 7, a plurality of In-doped well layers 611 are grown to form a group of well layer groups 61, and the In-doping concentration of each well layer 611 is decreased In the order of growth.
Specifically, 3-8 In layers are grownbGa(1-b)N forms a group of potential well layer groups 61, wherein b is more than 0.1 and less than 0.3, and the In doping concentration is reduced In sequence according to the growth sequence.
S4: as shown in fig. 8, barrier layer 62 is grown.
Specifically, Al is growncGa(1-c)N forms a barrier layer 62, where 0.1 < c < 0.3.
In some embodiments of the present invention, the method further comprises, before growing barrier layer 62:
growing a layer of AldGa(1-d)N forms an interfacial transition layer 621, where c < d < 0.3.
S5: as shown in fig. 9, the multiple quantum well region 6 is formed by alternately and repeatedly growing the well layer group 61 and the barrier layer 62.
Specifically, 3 to 8 pairs of potential well layer groups 61 and barrier layers 62 are alternately grown.
S6: as shown in fig. 10, a P-type semiconductor layer 7 is grown.
In some embodiments of the present invention, the method for manufacturing an LED epitaxial structure further includes a step of manufacturing a current blocking layer and other conventional LED epitaxial structures, which is not described herein again.
In summary, the electron enrichment layer with the gradually increasing In doping concentration and the potential well layer with the gradually decreasing In doping concentration are arranged, so that more electrons can be accumulated In the electron enrichment layer, electrons are provided for the light emitting layer, and the electron utilization rate is improved; secondly, the possibility of introducing structural defects such as dislocation, stacking fault, V-shaped defect, pore and the like due to stress mismatch In the epitaxial layer caused by In segregation is reduced, so that the lattice quality is enhanced; and thirdly, the potential energy difference at two ends of the quantum well is increased, the recombination efficiency of electrons and holes is increased, and the luminous efficiency is further improved. And each barrier layer is also provided with an Al-doped interface transition layer, and the Al doping concentration in the interface transition layer is higher than that in the barrier layer, so that the Al-doped interface moves forwards towards the potential well layer, and the descending relation of the Al doping concentration is formed between the interface transition layer and the barrier layer, thereby further enhancing the lattice quality.
It should be understood that although the present description refers to embodiments, not every embodiment contains only a single technical solution, and such description is for clarity only, and those skilled in the art should make the description as a whole, and the technical solutions in the embodiments can also be combined appropriately to form other embodiments understood by those skilled in the art.
The above detailed description is merely illustrative of possible embodiments of the present invention and is not intended to limit the scope of the invention, which is intended to include equivalent embodiments or modifications within the scope of the present invention without departing from the technical spirit of the present invention.

Claims (17)

1. An LED epitaxial structure, which sequentially comprises a substrate, a non-doped semiconductor layer, an N-type semiconductor layer, a multi-quantum well region and a P-type semiconductor layer from bottom to top,
the LED epitaxial structure further comprises at least one group of electron enrichment layer groups arranged below the multi-quantum well region, and a plurality of In-doped electron enrichment layers with sequentially increasing In doping concentration from bottom to top are stacked In each group of electron enrichment layer groups;
the multi-quantum well region comprises a plurality of potential well layer groups and barrier layers which are alternately stacked, and a plurality of In-doped potential well layers with In-doped concentrations decreasing from bottom to top are stacked In each potential well layer group.
2. The LED epitaxial structure of claim 1, wherein the number of the electron enrichment layer groups is 3-6, and the In doping concentration of the electron enrichment layer cyclically and periodically changes among multiple groups of the electron enrichment layer groups.
3. The LED epitaxial structure of claim 2, wherein each group of the electron enrichment layer is provided with 2-4 of the electron enrichment layers, and the electron enrichment layer is InaGa(1-a)N, wherein a is more than 0.1 and less than 0.3.
4. The LED epitaxial structure of claim 1, wherein 3-10 pairs of the well layer groups and the barrier layers are alternately stacked in the multi-quantum well region.
5. The LED epitaxial structure of claim 4, wherein 3-8 layers of the well layer are arranged In each group of the well layer group, and the well layer is InbGa(1-b)N, wherein b is more than 0.1 and less than 0.3.
6. LED epitaxy structure according to claim 4, characterised in that the barrier layer is AlcGa(1-c)N, wherein c is more than 0.1 and less than 0.3.
7. The LED epitaxial structure of claim 6, wherein an Al-doped interface transition layer is further disposed between each barrier layer and the underlying well layer group, the Al-doped concentration in the interface transition layer is higher than that in the barrier layer, and the interface transition layer is AldGa(1-d)N, wherein c is less than d and less than 0.3.
8. The LED epitaxial structure of claim 1, wherein an insertion layer is further disposed below each group of the potential well layer groups, and has a forbidden bandwidth smaller than that of the potential well layer, and the insertion layer is an InN layer and has a thickness ranging from 0.5 nm to 1 nm.
9. An LED device comprising the LED epitaxial structure of any one of claims 1 to 8, an N-electrode and a P-electrode, wherein the N-electrode is in ohmic contact with the N-type semiconductor layer and the P-electrode is in ohmic contact with the P-type semiconductor layer.
10. A preparation method of an LED epitaxial structure is characterized by comprising the following steps:
growing a non-doped semiconductor layer and a first N-type semiconductor layer on a substrate in sequence;
growing a plurality of In-doped electron enrichment layer groups to form a group of electron enrichment layer groups, wherein the In doping concentration of each electron enrichment layer is increased In sequence according to the growth sequence;
growing a plurality of layers of In-doped potential well layers to form a group of potential well layer groups, wherein the In doping concentration of each potential well layer is reduced In sequence according to the growth sequence;
growing a barrier layer;
alternately and repeatedly growing the potential well layer group and the barrier layer to form a multi-quantum well region;
and growing a P-type semiconductor layer.
11. The method for preparing an LED epitaxial structure according to claim 10, further comprising the steps of:
and repeatedly growing 2-5 groups of the electron enrichment layer groups on the electron enrichment layer groups, wherein In doping concentration of the electron enrichment layer cyclically and periodically changes among the electron enrichment layer groups.
12. The method for preparing an LED epitaxial structure according to claim 11, wherein the "growing a plurality of In-doped electron-rich layers" specifically comprises:
growing 2-4 layers of InaGa(1-a)N forms a group of the electron enrichment layer groups, wherein a is more than 0.1 and less than 0.3, and the In doping concentration is increased In sequence according to the growth sequence.
13. The method for preparing an LED epitaxial structure according to claim 10, further comprising, after growing the electron-rich layer group, the steps of:
growing an InN layer with the thickness ranging from 0.5 nm to 1nm to form an insertion layer.
14. The method for preparing an LED epitaxial structure according to claim 10, wherein 3 to 8 pairs of the potential well layer group and the barrier layer are alternately grown.
15. The method for preparing an LED epitaxial structure according to claim 14, wherein the "growing multiple In-doped well layers" specifically comprises:
growing 3-8 layers of InbGa(1-b)N forms a group of potential well layer groups, wherein b is more than 0.1 and less than 0.3, and the In doping concentration is as followsThe growth sequence decreases in turn.
16. The method for preparing an LED epitaxial structure according to claim 13, wherein the "growth barrier layer" specifically comprises:
growing AlcGa(1-c)N forms a barrier layer, wherein 0.1 < c < 0.3.
17. The method of claim 16, further comprising, before growing the barrier layer, the steps of:
growing a layer of AldGa(1-d)N forms an interface transition layer, wherein c < d < 0.3.
CN202011454243.4A 2020-12-10 2020-12-10 LED epitaxial structure, preparation method thereof and LED device Pending CN114628557A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116314506A (en) * 2023-04-10 2023-06-23 江苏第三代半导体研究院有限公司 Semiconductor epitaxial structure and preparation method and application thereof

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116314506A (en) * 2023-04-10 2023-06-23 江苏第三代半导体研究院有限公司 Semiconductor epitaxial structure and preparation method and application thereof

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