Epitaxial structure and light emitting diode

Abstract

The invention relates to the technical field of semiconductors, in particular to an epitaxial structure and a light emitting diode, and the epitaxial structure comprises a first semiconductor layer, an active layer and a second semiconductor layer which are stacked in sequence; the electron blocking layer is positioned between the active layer and the second semiconductor layer; the hole contribution layer is positioned between the electron blocking layer and the second semiconductor layer; the hole contribution layer comprises Mg ions, and the doping concentration of the Mg ions of the hole contribution layer is more than 7E19 cm <-3 >; and the doping thickness of Mg ions of the hole contribution layer is 10-2000 angstroms. Through the design of Mg ions in the hole contribution layer, the number of effective hole carriers is increased, and the internal quantum efficiency and the radiation recombination efficiency are further improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and particularly to an epitaxial structure and a light-emitting diode. Background Art

[0002] A light-emitting diode (LED) is a semiconductor light-emitting element, usually made of semiconductors such as GaN, GaAs, GaP, GaAsP, etc. Its core is a PN junction with light-emitting characteristics. LEDs have the advantages of high luminous intensity, high efficiency, small size, long service life, etc., and are considered to be one of the most potential light sources at present.

[0003] In traditional light-emitting diodes, due to the presence of relatively high indium ions in the active layer, the QCSE (quantum confinement Stark effect) is relatively serious, thus affecting the internal quantum efficiency. Therefore, how to allow more holes to enter the active layer to generate recombination light emission is an important technical problem. Summary of the Invention

[0004] In view of at least one deficiency of the above-mentioned prior art, an embodiment of the present invention provides an epitaxial structure, which at least includes a first semiconductor layer, an active layer, and a second semiconductor layer stacked in sequence; further includes an electron blocking layer located between the active layer and the second semiconductor layer; a hole contribution layer located between the electron blocking layer and the second semiconductor layer; the hole contribution layer contains Mg ions, and the doping concentration of Mg ions in the hole contribution layer is above 7E19 cm -3 above; the doping thickness of Mg ions in the hole contribution layer is 10 - 2000 angstroms.

[0005] The present invention also provides a light-emitting diode using the epitaxial structure as described in the above embodiment.

[0006] Based on the above, compared with the prior art, the epitaxial structure provided by the present invention is beneficial to increasing the number of effective hole carriers through the design of the hole contribution layer, thereby improving the internal quantum efficiency and the radiative recombination efficiency.

[0007] Other features and beneficial effects of the present invention will be described in the subsequent specification, and some of them will become obvious from the specification, or can be understood by implementing the present invention. The objectives and other beneficial effects of the present invention can be achieved and obtained through the structures specifically pointed out in the specification, claims, and drawings. Brief Description of the Drawings

[0008] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings; in the following description of the positional relationship of the drawings, unless otherwise specified, the directions shown by the components in the drawings are taken as the reference.

[0009] Figure 1 The cross-sectional schematic diagram of the epitaxial structure provided in the first embodiment of the present invention;

[0010] Figure 2 The cross-sectional schematic diagram of the epitaxial structure provided in the second embodiment of the present invention;

[0011] Figure 3 、 Figure 4 The cross-sectional schematic diagram of the epitaxial structure provided in the third embodiment of the present invention;

[0012] Figure 5 The cross-sectional schematic diagram of the epitaxial structure provided in the fourth embodiment of the present invention;

[0013] Figure 6 The cross-sectional schematic diagram of the light-emitting diode provided in the fifth embodiment of the present invention;

[0014] Figure 7 The top-view schematic diagram of the light-emitting diode provided in the fifth embodiment of the present invention;

[0015] Figure 8 The schematic diagram of the display provided in the sixth embodiment of the present invention.

[0016] Reference numerals:

[0017] 100 - epitaxial structure; 110 - first semiconductor layer; 120 - active layer; 121 / 121a - barrier layer; 122 - well layer; 130 - second semiconductor layer; 140 - electron blocking layer; 150 - hole contribution layer; 160 - transition layer; 161 - first transition layer; 162 - second transition layer; 162a - second barrier layer; 162b - second well layer; 163 - third transition layer; 163a - third barrier layer; 163b - third well layer; 200 - first electrode; 300 - second electrode; 400 - passivation layer; 500 - display unit. Detailed implementation manners

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. The technical features designed in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0019] In the description of the present invention, it should be noted that all terms (including technical terms and scientific terms) used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs, and should not be construed as a limitation to the present invention. It should be further understood that the terms used in the present invention should be understood as having a meaning consistent with their meaning in the context of this specification and the relevant art, and should not be understood in an idealized or overly formal sense, unless otherwise clearly defined in the present invention.

[0020] In some embodiments of the present invention, an epitaxial structure is provided. The epitaxial structure 100 at least includes a first semiconductor layer 110, an active layer 120, and a second semiconductor layer 130 that are sequentially stacked; it further includes an electron blocking layer 140 located between the active layer 120 and the second semiconductor layer 130, and a hole contribution layer 150 located between the electron blocking layer 140 and the second semiconductor layer 130. The hole contribution layer 150 contains Mg ions, and the doping concentration of Mg ions in the hole contribution layer 150 is above 7E19 cm -3 Above; the doping thickness of Mg ions in the hole contribution layer 150 is 10 - 2000 angstroms. Through the design of the hole contribution layer 150, it is beneficial to increase the number of effective hole carriers, thereby improving the internal quantum efficiency and the radiative recombination efficiency.

[0021] In some embodiments, the doping thickness of Mg ions in the hole contribution layer 150 is greater than 200 angstroms and less than or equal to 500 angstroms, or greater than or equal to 500 angstroms and less than or equal to 1000 angstroms, or greater than or equal to 1000 angstroms and less than or equal to 2000 angstroms to effectively increase the total amount of hole carriers.

[0022] In some embodiments, the doping concentration of Mg ions in the hole contribution layer 150 is below 1E21 cm -3 Below.

[0023] In some embodiments, the doping concentration of Mg ions in the hole contribution layer 150 increases in the direction close to the electron blocking layer 140 to facilitate the injection of holes into the active layer 120 more quickly.

[0024] In some embodiments, the electron blocking layer 140 is doped with Mg ions or not doped with Mg ions.

[0025] In some embodiments, when the electron blocking layer 140 is doped with Mg ions, the Mg ion doping concentration of the hole contribution layer 150 is more than 100 times that of the electron blocking layer 140, so as to ensure that more holes will tunnel through to the active layer 120 and recombine with the electrons blocked back by the electron blocking layer 140 under forward current drive, thereby improving the brightness of the LED chip.

[0026] In some embodiments, when the electron blocking layer 140 is doped with Mg ions, the Mg ion doping thickness of the hole contribution layer 150 is more than 20 times that of the electron blocking layer 140, which helps to increase the hole concentration and the hole injection efficiency.

[0027] In some embodiments, the active layer 120 includes M periods of well layers 122 and barrier layers 121 stacked alternately, where M is from 2 to 5, or from 6 to 15.

[0028] In some embodiments, the electron blocking layer 140 is GaN containing an Al component to more effectively block electron overflow; the barrier layer 121 in the active layer 120 contains an Al component, and the Al content in the electron blocking layer 140 is higher than that of the barrier layer 121 in the active layer 120, further improving the electron blocking effect and promoting the recombination efficiency of electrons and holes.

[0029] In some embodiments, the barrier layer 121a on the side of the active layer 120 close to the second semiconductor layer 130 is Al x1 In y1 Ga 0.5-x1-y1 N 0.5 , where 0≤x1≤0.5, 0≤y1≤0.5, and the well layer 122 is Al x2 In y2 Ga 1-x2-y2 N, where 0≤x2≤x1, y1<y2. By using indium element in the barrier layer 121a on the side of the active layer 120 close to the second semiconductor layer 130 to change the interface energy gap between the transition layer and the electron blocking layer 140, the high potential barrier between the transition layer and the electron blocking layer 140 is reduced, thereby increasing the hole injection.

[0030] In some embodiments, the indium composition of the barrier layer 121a on the side of the active layer 120 close to the second semiconductor layer 130 is higher than that of the other barrier layers 121 of the active layer 120. The indium composition of the barrier layer 121a closest to the second semiconductor layer 130 in the active layer 120 is 1.2 to 2 times, or 2 to 10 times, or more than 10 times that of the other barrier layers 121 of the active layer 120, so as to reduce the high barrier between the connecting layer and the electron blocking layer 140, thereby increasing the injection of holes.

[0031] In some embodiments, the energy gap of the barrier layer 121a on the side of the active layer 120 close to the second semiconductor layer 130 is lower than that of the other barrier layers 121 of the active layer 120, so as to reduce the high barrier between the barrier layer 121a and the electron blocking layer 140, thereby increasing the injection of holes.

[0032] In some embodiments, a transition layer 160 is further included, and the transition layer 160 is located between the active layer 120 and the first semiconductor layer 110 to reduce lattice defects.

[0033] In some embodiments, in the direction from the first semiconductor layer 110 to the second semiconductor layer 130, the transition layer 160 sequentially includes a first transition layer 161, a second transition layer 162, and a third transition layer 163 of the transition layer 160. The energy gap of the well layer 122 of the transition layer 160 gradually decreases. The second transition layer 162 is a periodic stacked structure of a second barrier layer 162a and a second well layer 162b, and the third transition layer 163 is a periodic stacked structure of a third barrier layer 163a and a third well layer 163b, which improves the lattice quality and electron deceleration effect on the side of the active layer 120 close to the first semiconductor layer 110, and further improves the internal quantum efficiency.

[0034] In some embodiments, the thickness of the transition layer 160 is 2000 Å to 7000 Å, wherein the thickness of the first transition layer 161 is 2000 Å ± 50%, the thickness of the second transition layer 162 is 2000 Å ± 50%, and the thickness of the third transition layer 163 is 2000 Å ± 50%, so as to effectively achieve electron deceleration and lattice matching.

[0035] In some embodiments, the In composition of the first transition layer 161 is less than the In composition of the second well layer 162b, which is less than the In composition of the third well layer 163b. The In composition of the first transition layer 161 is one-tenth to one-fifth of the In composition of the second well layer 162b, or the In composition of the first transition layer 161 is less than one-tenth of the In composition of the second well layer 162b. Setting a large gradient change in the In composition is beneficial to taking into account lattice quality and electron deceleration.

[0036] In some embodiments, the epitaxial structure 100 is a blue or green light epitaxial structure to more effectively reduce the QCSE phenomenon.

[0037] The present invention also provides a light-emitting diode, which adopts the epitaxial structure 100 described in any of the above embodiments to improve the performance of the light-emitting diode.

[0038] Next, in combination with different embodiments and the accompanying drawings of the specification, the product structure will be described and illustrated. The composition and dopants of each layer included in the epitaxial structure 100 of the present invention can be analyzed by any suitable method, such as a secondary ion mass spectrometer (SIMS). The thickness of each layer included in the epitaxial structure 100 of the present invention can be analyzed by any suitable method, such as a transmission electron microscope (TEM) or a scanning electron microscope (SEM), for matching the depth positions of each layer on, for example, the SIMS spectrum.

[0039] Embodiment 1

[0040] Please refer to Figure 1 , Embodiment 1 of the present invention discloses an epitaxial structure 100, which at least includes a first semiconductor layer 110, an active layer 120, and a second semiconductor layer 130 stacked in sequence, and also includes an electron blocking layer 140 and a hole contribution layer 150.

[0041] Among them, the first semiconductor layer 110 is a P-type layer that generates holes, and the second semiconductor layer 130 is an N-type layer that generates electrons. Electrons and holes move toward the active layer 120 respectively to generate recombination in the active layer 120, thereby realizing light emission.

[0042] The electron blocking layer 140 is located between the active layer 120 and the second semiconductor layer 130. Preferably, the electron blocking layer 140 is GaN containing an Al component, so as to reduce the overflow of electrons, and at the same time, it can also significantly reduce the dislocation density of the second semiconductor layer 130 in the epitaxial structure 100 and improve the injection efficiency of holes.

[0043] The hole contribution layer 150 is located between the electron blocking layer 140 and the second semiconductor layer 130, and is used to provide a sufficient hole concentration to improve the electron-hole recombination efficiency. Among them, the hole contribution layer 150 contains Mg ions, and the doping concentration of Mg ions in the hole contribution layer 150 is above 7E19 cm -3 ; the doping thickness of Mg ions in the hole contribution layer 150 is 10 - 2000 angstroms. If the thickness is too thick, it will cause serious light absorption in the hole contribution layer 150 and a decrease in the light emission efficiency. Preferably, the doping concentration of Mg ions in the hole contribution layer 150 is below 1E21 cm -3 to avoid too high a concentration.

[0044] In this embodiment, the QCSE phenomenon is reduced by limiting the doping of Mg ions in the hole contribution layer 150. Since the injection of the hole contribution layer 150 is limited even when a high concentration of Mg ions is doped, in this embodiment, the total amount of effective hole carriers is increased by increasing the doping thickness of Mg ions, that is, the doping thickness of Mg ions can be increased by increasing the thickness of the hole contribution layer 150. In this embodiment, it is preferred that the doping thickness of Mg ions in the hole contribution layer 150 is greater than or equal to 200 Å and less than or equal to 500 Å, or greater than or equal to 500 Å and less than or equal to 1000 Å, or greater than or equal to 1000 Å and less than or equal to 2000 Å.

[0045] By limiting the doping thickness of Mg ions in the hole contribution layer 150, the hole concentration in the active layer 120 can be effectively increased, the radiative recombination efficiency can be improved synchronously, and the internal quantum efficiency in the active layer 120 can also be significantly improved. It can be seen that by increasing the doping thickness of Mg ions in the hole contribution layer 150 and designing the Mg ion concentration, the performance of the epitaxial structure 100 can be improved.

[0046] Furthermore, the doping concentration of Mg ions in the hole contribution layer 150 increases in the direction close to the electron blocking layer 140, so as to facilitate the injection of holes into the active layer 120 more quickly.

[0047] The electron blocking layer 140 is doped with Mg ions or not doped with Mg ions. Since the hole concentration is affected by the doping efficiency and ionization efficiency of Mg in GaN, it is difficult to achieve a high level of the doping concentration of Mg in the hole contribution layer 150 and the hole concentration, resulting in a small amount of holes injected into the active region and uneven distribution, which further restricts the improvement of the internal quantum efficiency. Therefore, by doping Mg ions in the electron blocking layer 140 and increasing the thickness and concentration of Mg ions in the hole contribution layer 150, the hole concentration injected into the active layer 120 can be increased.

[0048] When the electron blocking layer 140 is doped with Mg ions, the doping concentration of Mg ions in the hole contribution layer 150 is more than 100 times that of the doping concentration of Mg ions in the electron blocking layer 140. That is, a lower doping concentration of Mg ions in the electron blocking layer 140 can avoid excessive Mg ions in the electron blocking layer 140 causing the diffusion of Mg into the active layer 120 to form non-radiative recombination, and a higher doping concentration of Mg ions in the hole contribution layer 150 can increase the hole concentration.

[0049] When the electron blocking layer 140 is doped with Mg ions, the Mg ion doping thickness of the hole contribution layer 150 is more than 20 times that of the electron blocking layer 140. That is, ensuring that the thickness of the electron blocking layer 140 is much lower than that of the hole contribution layer 150 can not only shorten the migration distance of holes to the active layer 120, but also contribute to the injection of holes into the active layer 120 and increase the hole concentration.

[0050] In this embodiment, it is preferable that the epitaxial structure 100 is a blue light epitaxial structure or a green light epitaxial structure. Since the In component of the active layer 120 in the blue light epitaxial structure and the green light epitaxial structure is higher, the QCSE phenomenon is more likely to occur. Therefore, applying the hole contribution layer 150 in this embodiment to the blue light epitaxial structure or the green light epitaxial structure can better play its role and more effectively reduce the QCSE phenomenon.

[0051] Embodiment Two

[0052] Please refer to Figure 2 , on the basis of Embodiment One, the active layer 120 is further refined. The active layer 120 includes M periods of well layers 122 and barrier layers 121 stacked alternately, where M is from 2 to 5 or from 6 to 15. The setting of M is related to the composition and thickness and will not be specifically limited here.

[0053] Preferably, when the electron blocking layer 140 is GaN containing an Al component and the barrier layer 121 in the active layer 120 contains an Al component, the Al content in the electron blocking layer 140 is higher than that in the barrier layer 121 of the active layer 120 to improve the electron blocking effect and relieve the electron overflow effect. At the same time, it can also play a role in reducing the activation energy of Mg ions, avoid the increase of the activation energy of Mg ions due to the high Al component in the active layer 120, increase the concentration of activated Mg ions, and thus promote the recombination efficiency of electrons and holes.

[0054] In some embodiments, the barrier layer 121a on the side of the active layer 120 close to the second semiconductor layer 130 is Al x1 In y1 Ga 0.5-x1-y1 N 0.5 , where 0 ≤ x1 ≤ 0.5 and 0 ≤ y1 ≤ 0.5. The other barrier layers 121 of the active layer 120 are GaN or AlGaN, and the well layer 122 of the active layer 120 is InGaN. In this embodiment, it is preferable that the well layer 122 is Al x2 In y2 Ga 1-x2-y2N, where 0 ≤ x2 ≤ x1 and y1 < y2. Since indium is a material with a relatively low energy gap, indium can be used in one or several of the last barrier layers 121a of the active layer 120 as a transition layer to change the interface energy gap between the transition layer and the electron blocking layer 140, so as to reduce the high barrier between the transition layer and the electron blocking layer 140, thereby increasing the injection of holes. For example, the last barrier layer 121a of the active layer 120 is set to 1 layer, 2 layers or 3 layers as the transition layer.

[0055] The barrier layer 121a closest to the second semiconductor layer 130 on one side of the active layer 120 serves as a transition layer, and the transition layer can be one to three layers. For example, through design, when M is 2 to 6 pairs, or 7 to 10 pairs, the transition layer is set to 1 layer. If the number of pairs of the transition layer is too large, the blocking effect on the second semiconductor layer 130 side of the active layer 120 will be reduced and electrons will overflow. When M is 11 to 15 layers, the transition layer is set to 2 layers or 3 layers to improve the internal quantum efficiency of the product.

[0056] Among them, the indium composition of the barrier layer 121a on the side of the active layer 120 close to the second semiconductor layer 130 is higher than that of the other barrier layers 121 of the active layer 120. The indium composition of the barrier layer 121a on the side of the active layer 120 closest to the second semiconductor layer 130 is 1.2 to 2 times, or 2 to 10 times, or more than 10 times that of the other barrier layers 121 of the active layer 120, so as to reduce the high barrier between the transition layer and the electron blocking layer 140, thereby increasing the injection of holes.

[0057] Furthermore, the energy gap of the barrier layer 121a on the side of the active layer 120 close to the second semiconductor layer 130 is lower than that of the other barrier layers 121 of the active layer 120, so as to reduce the high barrier between this layer and the electron blocking layer 140, thereby increasing the injection of holes.

[0058] Embodiment 3

[0059] Please refer to Figure 3 、 Figure 4 , on the basis of Embodiment 1 and Embodiment 2, this Embodiment 3 further includes a transition layer 160, and the transition layer 160 is located between the active layer 120 and the first semiconductor layer 110. The transition layer 160 is a single-layer gallium carbide, or a periodic stack of gallium nitride and indium gallium nitride layers, so as to play a role in reducing lattice defects. In other embodiments, the transition layer 160 includes a barrier layer 121 of the transition layer 160 and a well layer 122 of the transition layer 160, and the barrier layer 121 of the transition layer 160 includes aluminum gallium nitride or aluminum indium gallium nitride. Through the design of the transition layer 160 and the design of the hole contribution layer 150, the performance of the epitaxial structure 100 can be further improved.

[0060] Embodiment 4

[0061] Please refer to Figure 5 , on the basis of Embodiment 3, the transition layer 160 is refined. In the direction from the first semiconductor layer 110 to the second semiconductor layer 130, the transition layer 160 is successively composed of a first transition layer 161, a second transition layer 162, and a third transition layer 163 of the transition layer 160, and the energy gap of the well layer 122 of the transition layer 160 gradually decreases. The second transition layer 162 is a periodic stacked structure of a second barrier layer 162a and a second well layer 162b, and the third transition layer 163 is a periodic stacked structure of a third barrier layer 163a and a third well layer 163b, which improves the lattice quality and electron deceleration effect on the side of the first semiconductor layer 110 of the active layer 120, and further improves the internal quantum efficiency.

[0062] The aluminum composition of the third barrier layer 163a is higher than that of the second barrier layer 162a. The aluminum composition of the third barrier layer 163a is more than ten times that of the second barrier layer 162a, and the aluminum composition of the second barrier layer 162a is equal to or higher than that of the first transition layer 161. The aluminum composition gradually increases to improve the lattice quality and decelerate electrons.

[0063] The thickness of the transition layer 160 is 2000 Å to 7000 Å, wherein the thickness of the first transition layer 161 is 2000 Å ± 50%, the thickness of the second transition layer 162 is 2000 Å ± 50%, and the thickness of the third transition layer 163 is 2000 Å ± 50%. Combining the designs of the second transition layer 162 and the third transition layer 163 realizes electron deceleration and lattice matching.

[0064] The In composition of the first transition layer 161, the second well layer 162b, and the third well layer 163 gradually increases, that is, the In composition of the first transition layer 161 is less than the In composition of the second well layer 162b is less than the In composition of the third well layer 163b, wherein the In composition of the first transition layer 161 is one-tenth to one-fifth of the In composition of the second well layer 162b, or the In composition of the first transition layer 161 is less than one-tenth of the In composition of the second well layer 162b. Setting a large gradient change in the In composition is beneficial to taking into account both the lattice quality and electron deceleration.

[0065] In some embodiments, the first transition layer 161 is a single layer or a periodic multi-layer structure, and the first transition layer 161 includes aluminum gallium nitride and / or gallium nitride.

[0066] Embodiment 5

[0067] This embodiment also provides a light-emitting diode, and the light-emitting diode adopts any one of the epitaxial structures in Embodiments 1 to 4.

[0068] Preferably, as Figure 6 , Figure 7As shown, the light-emitting diode further includes a passivation layer 400 covering the epitaxial structure 100 to provide insulation protection. The light-emitting diode further includes a first electrode 200 and a second electrode 300 covering the passivation layer 400. Among them, the first electrode 200 is electrically connected to the first semiconductor layer 110, and the second electrode 300 is electrically connected to the second semiconductor layer 130.

[0069] Please continue to refer to Figure 6 and Figure 7 , in this embodiment, the light-emitting diode is rectangular, and at least one side dimension of the light-emitting diode is from 0 micrometers to 20 micrometers, or from 20 micrometers to 50 micrometers, that is, the short side length is from 0 micrometers to 20 micrometers, or from 20 micrometers to 50 micrometers, and the area of the light-emitting diode is not greater than 5000 square micrometers, including a micrometer-level PN junction.

[0070] It should be noted that the light-emitting diode provided in this embodiment is not limited to being applied in the light-emitting diodes of the horizontal structure or the flip-chip structure as Figure 6 shown, and can also be applied to the vertical structure.

[0071] Embodiment Six

[0072] Please refer to Figure 8 , this embodiment also provides a display device, including a circuit board and a display unit 500 electrically connected to the circuit board. The display unit 500 adopts any one of the epitaxial structures in Embodiments One to Four, or adopts the light-emitting diode in Embodiment Five.

[0073] In addition, those skilled in the art should understand that although there are many problems in the prior art, each embodiment or technical solution of the present invention can be improved in only one or several aspects, and it is not necessary to solve all the technical problems listed in the prior art or the background art at the same time. Those skilled in the art should understand that the content not mentioned in a claim should not be regarded as a limitation to that claim.

[0074] Although terms such as epitaxial structure, first semiconductor layer, active layer, second semiconductor layer, electron blocking layer, hole contribution layer, transition layer, second electrode, first electrode, passivation layer, etc. are used more in this article, the possibility of using other terms is not excluded. Using these terms is only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional limitation is contrary to the spirit of the present invention; the terms "first", "second", etc. (if any) in the specification and claims of the embodiments of the present invention and the above-mentioned drawings are used to distinguish similar objects and do not have to be used to describe a specific order or sequence.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An epitaxial structure, characterized in that, The epitaxial structure includes: a first semiconductor layer, an active layer, and a second semiconductor layer stacked in sequence; It further includes an electron blocking layer located between the active layer and the second semiconductor layer; A hole contribution layer, located between the electron blocking layer and the second semiconductor layer; the hole contribution layer contains Mg ions, and the doping concentration of Mg ions in the hole contribution layer is above 7E19 cm -3 or more; the doping thickness of Mg ions in the hole contribution layer is 10 to 2000 angstroms.

2. The epitaxial structure according to claim 1, characterized in that: The doping thickness of Mg ions in the hole contribution layer is greater than or equal to 200 Å and less than or equal to 500 Å, or greater than or equal to 500 Å and less than or equal to 1000 Å, or greater than or equal to 1000 Å and less than or equal to 2000 Å.

3. The epitaxial structure according to claim 1, characterized in that: The doping concentration of Mg ions in the hole contribution layer is below 1E21 cm -3 -3 4. The epitaxial structure according to claim 1, wherein: The doping concentration of Mg ions in the hole contribution layer increases in the direction close to the electron blocking layer.

5. The epitaxial structure according to claim 1, wherein: The electron blocking layer is doped with Mg ions or not doped with Mg ions.

6. The epitaxial structure according to claim 5, characterized in that: When the electron blocking layer is doped with Mg ions, the doping concentration of Mg ions in the hole contribution layer is more than 100 times that of the Mg ions in the electron blocking layer.

7. The epitaxial structure according to claim 5, wherein: When the electron blocking layer is doped with Mg ions, the doping thickness of Mg ions in the hole contribution layer is more than 20 times that of the Mg ions in the electron blocking layer.

8. The epitaxial structure according to claim 1, wherein: The active layer includes M periods of well layers and barrier layers stacked alternately, where M is 2 to 5, or 6 to 15.

9. The epitaxial structure according to claim 8, wherein: The electron blocking layer is GaN containing an Al component; the barrier layer in the active layer contains an Al component, and the Al content in the electron blocking layer is higher than that in the barrier layer in the active layer.

10. The epitaxial structure according to claim 8, characterized in that: The barrier layer on the side of the active layer close to the second semiconductor layer is Al x1 In y1 Ga 0.5-x1-y1 N 0.5 , where 0 ≤ x1 ≤ 0.5, 0 ≤ y1 ≤ 0.5, and the well layer is Al x2 In y2 Ga 1-x2-y2 N, where 0 ≤ x2 ≤ x1 and y1 < y2.

11. The epitaxial structure according to claim 10, wherein: The indium component of the barrier layer on the side of the active layer close to the second semiconductor layer is higher than that of the other barrier layers in the active layer. The indium component of the barrier layer on the side of the active layer closest to the second semiconductor layer is 1.2 to 2 times, or 2 to 10 times, or more than 10 times that of the other barrier layers in the active layer.

12. The epitaxial structure according to claim 10, characterized in that: The energy gap of the barrier layer on the side of the active layer close to the second semiconductor layer is lower than that of the other barrier layers in the active layer.

13. The epitaxial structure according to claim 1, characterized in that: It further includes a transition layer located between the active layer and the first semiconductor layer.

14. The epitaxial structure according to claim 13, wherein: In the direction from the first semiconductor layer to the second semiconductor layer, the transition layer includes a first transition layer, a second transition layer, and a third transition layer of the transition layer in sequence. The energy gap of the well layer in the transition layer gradually decreases. The second transition layer is a periodic stacked structure of a second barrier layer and a second well layer, and the third transition layer is a periodic stacked structure of a third barrier layer and a third well layer.

15. The epitaxial structure according to claim 14, wherein: The thickness of the transition layer is 2000 Å to 7000 Å, where the thickness of the first transition layer is 2000 Å ± 50%, the thickness of the second transition layer is 2000 Å ± 50%, and the thickness of the third transition layer is 2000 Å ± 50%.

16. The epitaxial structure according to claim 14, wherein: The In component of the first transition layer is less than the In component of the second well layer and less than the In component of the third well layer. Among them, the In component of the first transition layer is one-tenth to one-fifth of the In component of the second well layer, or the In component of the first transition layer is less than one-tenth of the In component of the second well layer.

17. The epitaxial structure according to claim 1, characterized in that: The epitaxial structure is a blue or green light epitaxial structure.

18. A light-emitting diode, characterized in that: An epitaxial structure as described in any one of claims 1 - 17 is adopted.

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