Light emitting diode epitaxial wafer and preparation method thereof

Abstract

The invention discloses a light-emitting diode epitaxial wafer and a preparation method thereof. By performing plasma treatment on a first AlGaN layer, the plasma can react with an N vacancy defect state surface layer on the surface of the first AlGaN layer to form a plasma-treated layer with high crystal quality and stable structure, thereby compensating for the problem of poor quality of the N vacancy defect state surface layer on the original first AlGaN layer, thereby improving the crystal quality of the epitaxial layer and further improving the luminous efficiency. Meanwhile, during the plasma treatment process, the plasma in an active state can adsorb oxygen atoms diffused from the substrate, thereby reducing the oxygen atom content on the first AlGaN layer, preventing the oxygen atoms from extending and diffusing into a multi-quantum well layer, and further improving the luminous efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor devices, and in particular to a light emitting diode epitaxial wafer and a preparation method thereof. Background Art

[0002] In recent years, AlGaN materials have attracted much attention due to their huge application potential in ultraviolet optoelectronic devices. Ultraviolet LEDs have the characteristics of high photon energy, short wavelength, small size, low power consumption, long life, and environmental friendliness. They are widely used in high color rendering index white light lighting, high-density optical data storage, sensors, lithography, air purification and environmental protection.

[0003] At present, when preparing AlGaN layer in epitaxial wafer structure, the reaction is generally carried out in NH3 environment. However, with the increase of Al component, the pre-reaction of Al and NH3 becomes more intense, resulting in more N vacancy defects in the epitaxially grown AlGaN layer, causing high defect density of AlGaN layer film and uneven surface, making the crystal quality of AlGaN layer inferior to that of GaN layer, resulting in low luminous efficiency of ultraviolet LED; at the same time, due to the decomposition of oxygen atoms from the oxide on the surface of the substrate at high temperature, it will diffuse upward with the growth of the epitaxial layer. When diffusing to the quantum well layer, it will absorb carriers to a certain extent, reducing the radiation recombination efficiency of carriers in the quantum well layer, further resulting in low luminous efficiency of ultraviolet LED.

[0004] Therefore, how to improve the luminous efficiency of ultraviolet LEDs has become an issue that urgently needs to be improved in existing ultraviolet LED technology. Summary of the invention

[0005] The present application aims to provide a light emitting diode epitaxial wafer and a preparation method thereof, so as to solve the problem of how to improve the luminous efficiency of ultraviolet LEDs.

[0006] The solution adopted by this application to solve the above technical problems is:

[0007] In a first aspect, the present application provides a light-emitting diode epitaxial wafer, comprising a substrate and a stacked structure arranged on the substrate, the stacked structure comprising at least a first AlGaN layer and a multi-quantum well layer arranged from bottom to top, a plasma-treated layer being arranged on one side of the first AlGaN layer close to the multi-quantum well layer, the plasma-treated layer being made by a surface layer of the first AlGaN layer and a plasma reaction, the surface layer being an N vacancy defect state surface layer.

[0008] In some embodiments of the present application, the plasma is nitrogen-containing plasma, and the plasma-treated layer is a GaN film.

[0009] In some embodiments of the present application, the first AlGaN layer includes an undoped AlGaN layer and an N-type doped AlGaN layer sequentially from bottom to top, and the plasma treated layer is grown on a side of the N-type doped AlGaN layer away from the undoped AlGaN layer.

[0010] In some embodiments of the present application, the N-type doped AlGaN layer includes an N vacancy defect state surface layer, and the plasma treated layer is formed by the reaction of the plasma with the N vacancy defect state surface layer.

[0011] In some embodiments of the present application, the plasma is N2O plasma.

[0012] In a second aspect, the present application also provides a method for preparing a light emitting diode epitaxial wafer, comprising the following steps:

[0013] providing a substrate;

[0014] Preparing a stacked structure on a substrate, the stacked structure comprising at least a first AlGaN layer and a multi-quantum well layer arranged from bottom to top;

[0015] After preparing the first AlGaN layer, performing plasma treatment on a side of the first AlGaN layer close to the multi-quantum well layer to form a plasma-treated layer;

[0016] The plasma treatment step includes plasma reacting with an N vacancy defect state surface layer of the first AlGaN layer to generate a plasma treated layer.

[0017] In some embodiments of the present application, the step of preparing the first AlGaN layer further includes the following steps:

[0018] Growing an undoped AlGaN layer on the buffer layer at high temperature;

[0019] An N-type doped AlGaN layer is grown on the undoped AlGaN layer, and the N-type doped AlGaN layer is Si-doped.

[0020] In some embodiments of the present application, in the step of preparing a plasma treatment layer, the substrate of the grown N-type doped AlGaN layer is placed at the negative pole position in the magnetron sputtering system, and a nitrogen-containing plasma is introduced at the positive pole position of the system, and then the plasma reacts with the N vacancy defect state surface of the N-type doped AlGaN layer to form a GaN film.

[0021] In some embodiments of the present application, the following steps are included:

[0022] A sapphire Al2O3 substrate is provided; a buffer layer is grown on the substrate by a physical vapor deposition method, and the buffer layer is subjected to in-situ annealing treatment; after the annealing is completed, an undoped AlGaN layer is grown on the buffer layer at high temperature, and the Al component is between 30% and 80%; a Si-doped N-type doped AlGaN layer is grown on the undoped AlGaN layer, and the Al component is between 20% and 60%; N2O plasma is introduced into the N-type doped AlGaN layer, and a plasma treatment layer is prepared by a radio frequency controlled sputtering method; a multi-quantum well layer is prepared on the plasma treatment layer by an MOCVD method, and the multi-quantum well layer is 5 to 12 periods of GaN / AlGaN, GaN is a well layer, and AlGaN is a barrier layer; an AlGaN electron blocking layer is grown on the multi-quantum well layer; and a P-type doped GaN layer is grown on the electron blocking layer, and the doping element is Mg.

[0023] In some embodiments of the present application, an AlGaN contact layer is also grown on the P-type doped GaN layer, and the entire epitaxial structure is annealed after the contact layer is prepared.

[0024] The light-emitting diode epitaxial wafer and preparation method provided by the present application perform plasma treatment on the first AlGaN layer, so that the plasma can react with the N vacancy defect state surface layer on the surface of the first AlGaN layer to form a plasma-treated layer with high crystal quality and stable structure, thereby compensating for the problem of poor quality of the N vacancy defect state surface layer on the original first AlGaN layer, thereby improving the crystal quality of the epitaxial layer and further improving the luminous efficiency; at the same time, during the plasma treatment process, the active plasma can adsorb the oxygen atoms diffused from the substrate, thereby reducing the oxygen atom content on the first AlGaN layer, preventing the oxygen atoms from extending and diffusing into the multi-quantum well layer, and further improving the luminous efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 It is a structural diagram of the epitaxial wafer of the present invention;

[0027] Figure 2 This is a step diagram of the epitaxial wafer preparation method of the present invention.

[0028] Element symbol description:

[0029] 1-substrate, 2-buffer layer, 3-undoped AlGaN layer, 4-N-type doped AlGaN layer, 5-plasma treated layer, 6-multi-quantum well layer, 7-electron blocking layer, 8-P-type doped GaN layer, 9-contact layer. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0031] In the description of the present invention, it is necessary to understand that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0032] In the application, the word "exemplary" is used to mean "serving as an example, illustration, or description". Any embodiment described in this application as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. The following description is given to enable any technician in the field to implement and use the invention. In the following description, details are listed for the purpose of explanation. It should be understood that a person of ordinary skill in the art can recognize that the present invention can be implemented without using these specific details. In other instances, known structures and processes are not described in detail to avoid obscuring the description of the invention with unnecessary details. Therefore, the present invention is not intended to be limited to the embodiments shown, but is consistent with the widest scope consistent with the principles disclosed in this application.

[0033] The development of AlGaN-based ultraviolet LEDs faces many technical difficulties, such as the small effective mass of electrons and high mobility, which makes it easy for electrons to overflow to the P layer through the quantum well; with the increase of Al component, it is easy to cause problems such as high defect density and uneven surface of epitaxially grown AlGaN films, and it is difficult to obtain AlGaN materials with high crystal quality. In addition, AlGaN materials with high Al component, whether N-type doping or P-type doping, are much more difficult than GaN materials, especially P-AlGaN doping is particularly difficult, and the activation efficiency of dopant Mg is low, resulting in insufficient holes and reduced radiation recombination efficiency; in addition, the internal quantum efficiency of AlGaN-based ultraviolet LEDs is much lower than that of blue-green light-emitting diodes, which seriously limits the performance of ultraviolet light-emitting diodes. In order to improve the quantum efficiency of ultraviolet LEDs, it is necessary to prepare p-type and n-type AlGaN materials with high conductivity, as well as epitaxial layers with high crystal quality and quantum well structures with high internal quantum efficiency.

[0034] At present, the internal quantum efficiency of AlGaN-based ultraviolet LEDs is much lower than that of blue-green light-emitting diodes. Due to the serious pre-reaction of Al and NH3, the growth of AlGaN materials requires a lower V / III ratio (the molar ratio of V-valent atoms to III-valent atoms, such as the molar ratio of N to Ga), which leads to the appearance of N vacancies in the AlGaN epitaxial layer, resulting in the epitaxial layer crystal quality of the AlGaN material being inferior to that of GaN, reducing the luminous efficiency of the ultraviolet LED. In addition, the oxygen atoms decomposed from the oxide on the surface of the substrate 1 at high temperature will diffuse upward with the growth of the epitaxial layer, which will also reduce the crystal quality of the epitaxial layer, causing the luminous efficiency of the ultraviolet LED to decrease.

[0035] The main body of the present embodiment is a light-emitting diode epitaxial wafer, including a substrate 1, a buffer layer 2 and a first AlGaN layer, a plasma treatment layer 5 is deposited on the first AlGaN layer, and a multi-quantum well layer 6, an electron blocking layer 7 and a second AlGaN layer are sequentially grown on the plasma treatment layer 5; the surface of the first AlGaN layer has an N vacancy defect state surface layer, and the plasma treatment layer 5 is used to react with the N vacancy defect state surface layer to grow a higher quality GaN film. By plasma treatment of the first AlGaN layer, the plasma can react with the N vacancy defect state surface layer on the surface of the first AlGaN layer to form a plasma treatment layer with high crystal quality and stable structure, which makes up for the poor quality of the N vacancy defect state surface layer on the original first AlGaN layer, thereby improving the crystal quality of the epitaxial layer and further improving the luminous efficiency; at the same time, during the plasma treatment process, the active plasma can adsorb the oxygen atoms diffused from the substrate, reducing the oxygen atom content on the first AlGaN layer, avoiding the oxygen atoms from extending and diffusing into the multi-quantum well layer, and further improving the luminous efficiency.

[0036] More specifically, the buffer layer 2 may not be included on the substrate 1, and other structural layers may be provided. As long as a plasma-treated layer 5 is provided on the AlGaN layer, and the plasma-treated layer also plays the role of filling N vacancy defects, or adsorbing diffused oxygen atoms in the bottom layer, they are all technical solutions for protection of this embodiment.

[0037] In some embodiments of the present application, the plasma treatment layer 5 is sputtered on the first AlGaN layer by introducing plasma, and the plasma is N2O plasma. Similarly, other plasmas that can fill N vacancy defects can also be used for treatment, not limited to only N2O plasma, such as N2 plasma. More specifically, other nitrogen-containing plasmas that can absorb and block oxygen atoms can also be used for treatment, which also achieves the effect of improving the luminous efficiency of LEDs.

[0038] In some embodiments of the present application, the first AlGaN layer includes an undoped AlGaN layer 3 and an N-type doped AlGaN layer 4 grown sequentially on the buffer layer 2, and the plasma treated layer 5 is grown on the surface of the N-type doped AlGaN layer 4. The N-type doped AlGaN layer 4 is Si-doped, with a thickness of 1.0-3.0 microns, a growth temperature of 1100°C-1200°C, a pressure of 50 Torr to 100 Torr, and a Si doping concentration of 1019 cm -3 -1020cm -3 The Al content is between 20% and 60%. The growth temperature of the undoped AlGaN layer 3 is 1000° C.-1200° C., the pressure range is 150 Torr-500 Torr, and the growth time is between 5 minutes and 10 minutes.

[0039] In some embodiments of the present application, the second AlGaN layer includes a P-type doped AlGaN layer, a contact layer 9 is provided on the surface of the P-type doped AlGaN layer, and the contact layer 9 includes an AlGaN structure. The thickness is between 10nm and 50nm, the growth temperature range is 1000℃-1100℃, the growth pressure range is 50Torr-100Torr, and the Al component is between 0%-30%.

[0040] See also Figure 1, a light emitting diode epitaxial wafer of the present embodiment comprises a substrate 1, a buffer layer 2, an undoped AlGaN layer 3, an N-type doped AlGaN layer 4, a plasma treated layer 5, a multi-quantum well layer 6 (MQW), an electron blocking layer 7 (EBL), a P-type doped GaN layer 8 and a contact layer 9 which are arranged in sequence. Oxygen atoms on the substrate 1 will diffuse upward along the buffer layer 2, the undoped AlGaN layer 3 and the N-type doped AlGaN layer 4. If the oxygen atoms diffuse to the multi-quantum well layer 6, they will absorb the carriers of the multi-quantum well layer 6, which will reduce the luminous efficiency of the LED; by arranging the plasma treated layer 5 before the multi-quantum well layer 6, the plasma on the plasma treated layer 5 adsorbs the oxygen atoms, intercepts the oxygen atoms that are about to enter the multi-quantum well layer 6, and thus improves the radiation recombination efficiency of the carriers in the multi-quantum well layer 6. At the same time, since N-type doped AlGaN layer 4 will have N vacancy defects during growth, which will also affect the morphology of multi-quantum well layer 6, the N vacancy defects of N-type doped AlGaN layer 4 can be compensated by setting plasma treatment layer 5, thereby improving the crystal quality of epitaxial layer.

[0041] By treating the N-type doped AlGaN layer with N2O plasma, due to the serious pre-reaction of Al and NH3, the growth of AlGaN material requires a lower V / III ratio condition, resulting in the appearance of N vacancies in the AlGaN epitaxial layer, making the crystal quality of the epitaxial layer poor, thereby reducing the luminous efficiency of the ultraviolet LED. The substrate on which the epitaxial layer has been grown is located at the negative pole of the power supply of the magnetron sputtering system, and is treated with N2O plasma. The N atoms in the N2O plasma carry positive charges and move to the epitaxial layer located at the negative pole under the action of the electric field, and combine with the Ga atoms in the N vacancy defect state in the epitaxial layer to form a GaN film, thereby improving the crystal quality of the AlGaN epitaxial layer; in addition, the oxide on the surface of the substrate will decompose oxygen atoms during the epitaxial process and diffuse upward with the growth of the epitaxial layer. When diffusing to the quantum well layer, it will absorb carriers to a certain extent, thereby reducing the radiation recombination efficiency of carriers in the quantum well, causing the luminous efficiency of the ultraviolet LED to decrease. By treating it with N2O plasma, the negatively charged oxygen atoms decomposed from the oxide on the surface of the substrate move toward the N2O plasma at the positive electrode under the action of the electric field, and combine with the oxygen atoms in the N2O plasma to generate oxygen molecules, which prevents the oxygen atoms from diffusing into the quantum wells, thereby improving the luminous efficiency of the ultraviolet LED.

[0042] The main body of this embodiment is a method for preparing a light-emitting diode epitaxial wafer, comprising the following steps: providing a substrate 1; preparing a buffer layer 2 on the substrate 1, and then preparing a first AlGaN layer on the buffer layer 2; preparing a plasma-treated layer 5 on the first AlGaN layer to compensate for the N vacancy defects on the first AlGaN layer; and sequentially growing a multi-quantum well layer 6, an electron blocking layer 7, and a second AlGaN layer on the plasma-treated layer 5.

[0043] In some embodiments of the present application, in the step of preparing the plasma-treated layer 5, it includes introducing N2O plasma and adopting a radio frequency controlled sputtering method for preparation. In some embodiments of the present application, in the step of preparing the first AlGaN layer, it also includes the following steps: growing an undoped AlGaN layer 3 on the buffer layer 2 at high temperature; growing an N-type doped AlGaN layer 4 on the undoped AlGaN layer 3, and the N-type doped AlGaN layer 4 is Si-doped. In some embodiments of the present application, in the step of preparing the second AlGaN layer, it includes growing a P-type doped AlGaN layer on the electron blocking layer 7, and the P-type doping is Mg-doping.

[0044] See also Figure 2 In some embodiments of the present application, the following steps are included: S1: providing a sapphire Al2O3 substrate 1; S2: growing a buffer layer 2 on the substrate 1 by physical vapor deposition, and performing in-situ annealing on the buffer layer 2; S3: after the annealing is completed, growing an undoped AlGaN layer 3 on the buffer layer 2 at a high temperature, and the Al component is between 30% and 80%; S4: growing a Si-doped N-type doped AlGaN layer 4 on the undoped AlGaN layer 3, and the Al component is between 20% and 60%; S5: N2O plasma is introduced into the N-type doped AlGaN layer 4, and a plasma treatment layer 5 is prepared by a radio frequency controlled sputtering method; S6: A multi-quantum well layer 6 is prepared on the plasma treatment layer 5 by a MOCVD method, wherein the multi-quantum well layer 6 is 5 to 12 periods of GaN / AlGaN, GaN is a well layer, and AlGaN is a barrier layer; S7: An AlGaN electron blocking layer 7 is grown on the multi-quantum well layer 6; S8: A P-type doped GaN layer 8 is grown on the electron blocking layer 7, and the doping element is Mg. S9: An AlGaN contact layer 9 is grown on the P-type doped GaN layer 8, and after the contact layer 9 is prepared, the overall epitaxial structure is annealed.

[0045] Embodiment 1: This embodiment provides an epitaxial preparation method of an AlGaN-based ultraviolet light-emitting diode. A substrate 1 is a sapphire Al2O3 substrate 1 with a (0001) crystal orientation.

[0046] Step 1: Grow an AlN buffer layer 2 on a substrate 1 by PVD. The growth temperature is 400-650° C., the sputtering power is 2000-4000 W, and the pressure is 1-10 torr; grow an AlN buffer layer 2 with a thickness of 15 to 50 nm.

[0047] Step 2: The buffer layer 2 is subjected to in-situ annealing treatment in a hydrogen atmosphere in MOCVD at a temperature of 1000° C.-1200° C., a pressure range of 150 Torr-500 Torr, and a time range of 5 minutes to 10 minutes.

[0048] Step 3: After annealing, the temperature is adjusted to 1050°C-1200°C, and undoped AlGaN with a thickness of 1.0 to 3.0 microns is grown. The growth pressure is between 50 Torr and 100 Torr, and the Al component is between 0.3-0.8.

[0049] Step 4: After the undoped AlGaN layer is grown, a Si-doped N-type AlGaN layer is grown with a thickness between 1.0 and 3.0 μm, a growth temperature between 1100°C and 1200°C, a pressure between 50 Torr and 100 Torr, and a Si doping concentration of 1019 cm -3 -1020cm -3 The Al component is between 0.2-0.6.

[0050] Step 5: After the growth of the N-type doped AlGaN layer 4 is completed, it is cooled to room temperature and transferred into the RF magnetron sputtering system. The N2O plasma is located at the positive pole of the magnetron sputtering system power supply, and the substrate on which the epitaxial layer has been grown is located at the negative pole of the magnetron sputtering system power supply. It is subjected to N2O plasma treatment for 30-60 minutes, with a sputtering power of 100-500W, a N2O flow rate of 20-50sccm, a temperature of 100-200°C, and a pressure of 1-10torr.

[0051] Step 6: After the N2O plasma treatment is completed, the multi-quantum well structure (MQW) is grown in MOCVD. The multi-quantum well layer 6 (MQW) is composed of 5 to 12 periods of GaN / AlGaN, wherein GaN is a well layer and AlGaN is a barrier layer. The thickness of a single GaN well layer in the MQW is 2-4 nm, the growth temperature ranges between 900°C and 1000°C, and the pressure ranges between 50 Torr and 200 Torr; the thickness of a single AlGaN barrier layer is between 8-20 nm, the growth temperature is between 1000°C and 1100°C, the growth pressure is between 50 Torr and 100 Torr, and the Al component is between 0.1 and 0.5.

[0052] Step 7: After the multi-quantum well layer 6 is grown, an AlGaN electron blocking layer 7EBL26 is grown, with a growth temperature between 1000° C. and 1100° C., a growth pressure between 50 Torr and 100 Torr, a growth thickness between 20 nm and 100 nm, and an Al component between 0.1-0.5.

[0053] Step 8: After the electron blocking layer 7EBL is grown, a P-type doped GaN layer 8 is grown with a thickness between 30nm and 200nm, a growth temperature between 950℃-1050℃, a growth pressure range of 50Torr-300Torr, and a Mg doping concentration of 1019cm -3 -1020cm -3 between.

[0054] Step 9: Grow AlGaN contacts on the P-type doped GaN layer 8 with a thickness between 10 nm and 50 nm, a growth temperature range of 1000° C.-1100° C., a growth pressure range of 50 Torr-100 Torr, and an Al component between 0.0-0.3.

[0055] Step 10: After the epitaxial structure growth is completed, the temperature of the reaction chamber is lowered and annealing is performed in a nitrogen atmosphere at a temperature range of 650°C-850°C for 5 to 15 minutes until the epitaxial growth at room temperature is completed.

[0056] In this embodiment, trimethylaluminum (TMAl), trimethylgallium or triethylgallium (TMGa or TEGa), and NH3 are used as precursors of group III source and group V source, respectively, silane and bismuth magnesium are used as precursors of N-type dopant and P-type dopant, respectively, and N2 and H2 are used as carrier gases.

[0057] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the detailed description of other embodiments above, and will not be repeated here.

[0058] The basic concepts have been described above. Obviously, for those skilled in the art, the above detailed disclosure is only for example and does not constitute a limitation of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of the present application.

[0059] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0060] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus help understand one or more embodiments of the invention, in the above description of the embodiments of this application, multiple features are sometimes combined into one embodiment, figure or description thereof. However, this disclosure method does not mean that the features required by the object of this application are more than the features mentioned in the claims. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0061] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of the present application are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0062] Each patent, patent application, patent application publication, and other materials, such as articles, books, specifications, publications, documents, etc., cited in this application is hereby incorporated by reference in its entirety, except for application history documents that are inconsistent with or conflicting with the content of this application, and documents that limit the broadest scope of the claims of this application (currently or later attached to this application). It should be noted that if the descriptions, definitions, and / or use of terms in the accompanying materials of this application are inconsistent or conflicting with the content of this application, the descriptions, definitions, and / or use of terms in this application shall prevail.

[0063] The technical solutions provided in the embodiments of the present application are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A light emitting diode epitaxial wafer, characterized in that: The invention comprises a substrate and a stacked structure arranged on the substrate, wherein the stacked structure comprises at least a first AlGaN layer and a multi-quantum well layer arranged from bottom to top, a plasma-treated layer is arranged on a side of the first AlGaN layer close to the multi-quantum well layer, the plasma-treated layer is made by a surface layer of the first AlGaN layer and a plasma reaction in a magnetron sputtering system, the surface layer is an N vacancy defect state surface layer; the plasma is a nitrogen-containing plasma, and the plasma-treated layer is a GaN film; the first AlGaN layer comprises an undoped AlGaN layer and an N-type doped AlGaN layer sequentially from bottom to top, and the plasma-treated layer is grown on a side of the N-type doped AlGaN layer away from the undoped AlGaN layer.

2. The light emitting diode epitaxial wafer according to claim 1, characterized in that: The N-type doped AlGaN layer includes an N vacancy defect state surface layer, and the plasma treated layer is formed by the reaction of the plasma and the N vacancy defect state surface layer.

3. The light emitting diode epitaxial wafer according to claim 1, characterized in that: The plasma is N2O plasma.

4. A method for preparing a light emitting diode epitaxial wafer, characterized in that: The following steps are involved: providing a substrate; Preparing a stacked structure on a substrate, the stacked structure comprising at least a first AlGaN layer and a multi-quantum well layer arranged from bottom to top; After preparing the first AlGaN layer, performing plasma treatment on a side of the first AlGaN layer close to the multi-quantum well layer to form a plasma-treated layer; The plasma treatment step includes plasma reacting with the N vacancy defect state surface layer of the first AlGaN layer to form a plasma treated layer; the step of preparing the first AlGaN layer also includes the following steps: High temperature growth of undoped AlGaN layer; Growing an N-type doped AlGaN layer on the undoped AlGaN layer, wherein the N-type doped AlGaN layer is doped with Si; The step of preparing the plasma treatment layer includes placing the grown N-type doped AlGaN layer substrate at the negative pole position in the magnetron sputtering system, introducing nitrogen-containing plasma at the positive pole position of the system, and then reacting the plasma with the N vacancy defect state surface of the N-type doped AlGaN layer to form a GaN film.

5. The method for preparing a light emitting diode epitaxial wafer according to claim 4, characterized in that: The following steps are involved: Providing a sapphire Al2O3 substrate; A buffer layer is grown on the substrate by using a physical vapor deposition method, and the buffer layer is subjected to an in-situ annealing treatment; After annealing, an undoped AlGaN layer is grown on the buffer layer at high temperature, and the Al component is between 30% and 80%; Growing a Si-doped N-type doped AlGaN layer on the undoped AlGaN layer, wherein the Al component is between 20% and 60%; N2O plasma is introduced into the N-type doped AlGaN layer, and a plasma treatment layer is prepared by a radio frequency controlled sputtering method; Prepare a multi-quantum well layer on the plasma treated layer by MOCVD method, wherein the multi-quantum well layer is 5 to 12 periods of GaN / AlGaN, GaN is a well layer, and AlGaN is a barrier layer; Growing an AlGaN electron blocking layer on the multi-quantum well layer; A P-type doped GaN layer is grown on the electron blocking layer, and the doping element is Mg.

6. The method for preparing a light emitting diode epitaxial wafer according to claim 5, characterized in that: The method also includes growing an AlGaN contact layer on the P-type doped GaN layer, and performing annealing on the entire epitaxial structure after the contact layer is prepared.

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