Light-emitting diode epitaxial wafer, preparation method thereof and LED

Abstract

The invention relates to the technical field of photoelectricity, and discloses a light-emitting diode epitaxial wafer and a preparation method thereof, and an LED, the light-emitting diode epitaxial wafer comprises a substrate, and the substrate is sequentially provided with a buffer layer, a non-doped GaN layer, an N-type GaN layer, a stress release layer, a multi-quantum well layer, an electron blocking layer, and a P-type GaN layer; the buffer layer comprises at least one group of composite layers, and each composite layer comprises a GaN layer, an AlGaN layer and an InGaN layer which are stacked in sequence. The light-emitting diode epitaxial wafer provided by the invention is beneficial to improving the integrity of laser lift-off and the yield of a final chip.

Description

Technical Field

[0001] The invention relates to the field of optoelectronic technology, and in particular to a light emitting diode epitaxial wafer and a preparation method thereof, and an LED. Background Art

[0002] LED chips are semiconductor electronic components that can emit light. They are small in size, high in brightness, and low in energy consumption. They are widely used in lighting and other fields. LED chips are obtained by splitting LED epitaxial wafers. LED epitaxial wafers include a substrate and a GaN epitaxial layer grown on the substrate.

[0003] At present, materials such as sapphire, silicon or silicon carbide are often used as substrates. Taking sapphire substrates as an example, with the continuous iteration and improvement of chip technology, the design and structure of chips have also become diversified. Micro-LED chips, due to chip size, and vertical structure chips, due to their structural design and application, all require the sapphire substrate in the epitaxial wafer to be peeled off, leaving only the epitaxy in the chip structure. The current mainstream peeling methods are wet etching peeling technology and laser peeling technology. The application of laser peeling technology in sapphire substrate epitaxy is relatively mature, but the peeling integrity and yield of existing technologies still have a lot of room for improvement. Among them, laser peeling equipment and epitaxial structure are both key influencing factors. Therefore, how to develop an epitaxial structure that is conducive to laser peeling has become an important technical breakthrough point at present. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a light emitting diode epitaxial wafer, which is beneficial to improving the integrity of laser lift-off and the yield of the final chip.

[0005] The technical problem to be solved by the present invention is to provide a method for preparing a light emitting diode epitaxial wafer, which has a simple process and can stably prepare a light emitting diode epitaxial wafer with good luminous efficiency.

[0006] In order to solve the above technical problems, the present invention provides a light-emitting diode epitaxial wafer, comprising a substrate, on which a buffer layer, a non-doped GaN layer, an N-type GaN layer, a stress release layer, a multi-quantum well layer, an electron blocking layer, and a P-type GaN layer are sequentially arranged;

[0007] The buffer layer includes at least one group of composite layers, and the composite layer includes a GaN layer, an AlGaN layer and an InGaN layer stacked in sequence.

[0008] In some embodiments, the buffer layer includes 1 to 5 groups of composite layers stacked in sequence.

[0009] In some embodiments, the GaN layer has a thickness of 0.1 nm to 3 nm.

[0010] In some embodiments, the AlGaN layer has a thickness of 0.1 nm to 3 nm.

[0011] In some embodiments, the thickness of the InGaN layer is 0.1 nm to 3 nm.

[0012] In some embodiments, the buffer layer has a thickness of 3 nm to 40 nm.

[0013] Accordingly, the present invention also provides a method for preparing a light emitting diode epitaxial wafer, comprising the following steps:

[0014] S1. providing a substrate;

[0015] S2, depositing a buffer layer, an undoped GaN layer, an N-type GaN layer, a stress release layer, a multi-quantum well layer, an electron blocking layer, and a P-type GaN layer on the substrate in sequence;

[0016] The buffer layer includes at least one group of composite layers, and the composite layer includes a GaN layer, an AlGaN layer and an InGaN layer stacked in sequence.

[0017] In some embodiments, the buffer layer is grown at a temperature of 500° C. to 800° C. and a pressure of 100 torr to 500 torr.

[0018] In some embodiments, when the GaN layer is grown, a Ga source, NH3 gas, N2 gas and H2 gas are introduced;

[0019] When the InGaN layer is grown, a Ga source, an In source, NH3 gas and N2 gas are introduced;

[0020] When the AlGaN layer is grown, a Ga source, an Al source, NH3 gas, N2 gas and H2 gas are introduced.

[0021] Correspondingly, the present invention further provides an LED, which includes the light-emitting diode epitaxial wafer as described above, or includes the light-emitting diode epitaxial wafer manufactured by the method for manufacturing the light-emitting diode epitaxial wafer as described above.

[0022] The implementation of the present invention has the following beneficial effects:

[0023] In the light-emitting diode epitaxial wafer provided by the present invention, the buffer layer comprises at least one group of composite layers, and the composite layers comprise a GaN layer, an AlGaN layer and an InGaN layer stacked in sequence.

[0024] The principle of laser lift-off is to transfer the device to the terminal substrate by laser irradiation-induced material ablation. The sapphire substrate is a material with aluminum oxide (Al2O3) single crystal as the main component. The sapphire substrate epitaxial wafer is GaN grown on Al2O3. The laser will absorb the ablation at the interface between Al2O3 and GaN so that the epitaxial layer can be peeled off. Increasing the absorption rate of the laser at the interface can facilitate the peeling of the epitaxial layer. InGaN can have a good light absorption efficiency due to its optical properties. The introduction of InGaN in the buffer layer can better absorb the laser so that the ablation is concentrated at the interface between Al2O3 and GaN, thereby improving the completeness of the peeling. However, due to the more serious lattice mismatch between InGaN and sapphire, in order to improve the crystal quality of the subsequent epitaxial layer, the GaN layer and the AlGaN layer are grown before the InGaN layer is grown. In addition, since the buffer layer needs to be grown at a relatively low temperature, a good interface layer cannot be formed. Therefore, the periodic composite layer of GaN / AlGaN / InGaN is used to better absorb the laser and improve the completeness of the peeling, thereby improving the completeness of the laser lift-off and the yield of the final chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic structural diagram of the light emitting diode epitaxial wafer provided by the present invention. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. In addition, it should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0027] In the description of the present invention, it is necessary to understand that the terms "length", "width", "up", "down", "left", "right", "horizontal", "top", "bottom", etc. indicate orientations or positional relationships based on the orientations 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 a limitation on the present invention.

[0028] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0029] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0031] The disclosure below provides many different embodiments or examples to realize different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the examples of various specific processes and materials provided by the present invention, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0032] In the present invention, "preferred" and "better" are only used to describe implementation methods or embodiments with better effects, and it should be understood that they do not constitute a limitation on the scope of protection of the present invention. In the present invention, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features. In the present invention, when involving numerical ranges, unless otherwise specified, the two endpoints of the numerical range are included.

[0033] To solve the above problems, the present invention provides a light emitting diode epitaxial wafer, such as Figure 1 As shown, it includes a substrate 100, on which a buffer layer 200, a non-doped GaN layer 300, an N-type GaN layer 400, a stress release layer 500, a multi-quantum well layer 600, an electron blocking layer 700, and a P-type GaN layer 800 are sequentially arranged;

[0034] The buffer layer 200 includes at least one group of composite layers 210 , and the composite layer 210 includes a GaN layer 211 , an AlGaN layer 212 , and an InGaN layer 213 stacked in sequence.

[0035] The specific structure of the buffer layer 200 provided by the present invention is as follows:

[0036] In some embodiments, the buffer layer 200 includes 1 to 5 groups of sequentially stacked composite layers 210. Exemplarily, the buffer layer 200 includes 1 or 2 or 3 or 4 or 5 groups of sequentially stacked composite layers 210. The number of cycles needs to be within a reasonable range. After all, the crystal quality of the buffer layer is relatively poor, and a large number of defects will be generated here. Too many cycles are likely to cause too many defects, thereby affecting the growth of the subsequent epitaxial layer and affecting the final performance.

[0037] In some embodiments, the thickness of the buffer layer 200 is 3 nm to 40 nm; exemplary thicknesses of the buffer layer 200 are 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, and 40 nm, but are not limited to the above examples.

[0038] In some embodiments, the thickness of the GaN layer 211 is 0.1nm to 3nm; exemplary thicknesses of the GaN layer 211 are 0.3nm, 0.6nm, 0.9nm, 1nm, 1.3nm, 1.6nm, 1.9nm, 2nm, 2.3nm, 2.6nm, 2.9nm, 3nm, not limited to the above. Preferably, the thickness of the GaN layer 211 is 0.5nm to 2nm. The light-emitting diode chip manufactured within the preferred range has better laser lift-off integrity, higher yield and light-emitting performance.

[0039] In some embodiments, the thickness of the AlGaN layer 212 is 0.1nm to 3nm; exemplary thicknesses of the AlGaN layer 212 are 0.3nm, 0.6nm, 0.9nm, 1nm, 1.3nm, 1.6nm, 1.9nm, 2nm, 2.3nm, 2.6nm, 2.9nm, 3nm, not limited to the above. Preferably, the thickness of the AlGaN layer 212 is 0.5nm to 2nm. The light-emitting diode chip manufactured within the preferred range has better laser lift-off integrity, higher yield and light-emitting performance.

[0040] In some embodiments, the thickness of the InGaN layer 213 is 0.1nm to 3nm; exemplary thicknesses of the InGaN layer 213 are 0.3nm, 0.6nm, 0.9nm, 1nm, 1.3nm, 1.6nm, 1.9nm, 2nm, 2.3nm, 2.6nm, 2.9nm, 3nm, not limited to the above. Preferably, the thickness of the InGaN layer 213 is 0.5nm to 2nm. The light-emitting diode chip manufactured within the preferred range has better laser lift-off integrity, higher yield and luminescence performance.

[0041] In the light-emitting diode epitaxial wafer provided in the above embodiment, the buffer layer 200 includes at least one group of composite layers 210 , and the composite layer 210 includes a GaN layer 211 , an AlGaN layer 212 , and an InGaN layer 213 stacked in sequence.

[0042] The principle of laser lift-off is to transfer the device to the terminal substrate by laser irradiation-induced material ablation. The sapphire substrate is a material with aluminum oxide (Al2O3) single crystal as the main component. The sapphire substrate epitaxial wafer is GaN grown on Al2O3. The laser will absorb the ablation at the interface between Al2O3 and GaN so that the epitaxial layer can be peeled off. Increasing the absorption rate of the laser at the interface can facilitate the peeling of the epitaxial layer. InGaN can have a good light absorption efficiency due to its optical properties. The introduction of InGaN in the buffer layer can better absorb the laser so that the ablation is concentrated at the interface between Al2O3 and GaN, thereby improving the completeness of the peeling. However, due to the more serious lattice mismatch between InGaN and sapphire, in order to improve the crystal quality of the subsequent epitaxial layer, the GaN layer and the AlGaN layer are grown before the InGaN layer is grown. In addition, since the buffer layer needs to be grown at a relatively low temperature, a good interface layer cannot be formed. Therefore, the periodic composite layer of GaN / AlGaN / InGaN is used to better absorb the laser and improve the completeness of the peeling, thereby improving the completeness of the laser lift-off and the yield of the final chip.

[0043] Accordingly, the present invention provides a method for preparing a light emitting diode epitaxial wafer, comprising the following steps:

[0044] S1, providing a substrate 100;

[0045] In some embodiments, the substrate 100 may be selected from one of a sapphire substrate, a SiO2 sapphire composite substrate, a silicon substrate, a silicon carbide substrate, a gallium nitride substrate, and a zinc oxide substrate. Preferably, the substrate 100 is a sapphire substrate, which is a commonly used GaN-based LED substrate material. The sapphire substrate has a mature preparation process, a low price, is easy to clean and handle, and has good stability at high temperatures.

[0046] S2, sequentially depositing a buffer layer 200, a non-doped GaN layer 300, an N-type GaN layer 400, a stress release layer 500, a multi-quantum well layer 600, an electron blocking layer 700, and a P-type GaN layer 800 on the substrate 100;

[0047] The buffer layer 200 includes at least one group of composite layers 210 , and the composite layer 210 includes a GaN layer 211 , an AlGaN layer 212 , and an InGaN layer 213 stacked in sequence.

[0048] Specifically, the above step S2 specifically includes the following steps:

[0049] S21 , depositing the buffer layer 200 on the substrate 100 .

[0050] In some embodiments, the growth temperature of the buffer layer is 500° C. to 800° C., and the growth pressure is 100 torr to 500 torr.

[0051] In some embodiments, when the GaN layer is grown, a Ga source, NH3 gas, N2 gas and H2 gas are introduced;

[0052] When the InGaN layer is grown, a Ga source, an In source, NH3 gas and N2 gas are introduced;

[0053] When the AlGaN layer is grown, a Ga source, an Al source, NH3 gas, N2 gas and H2 gas are introduced.

[0054] S22 , depositing the undoped GaN layer 300 on the buffer layer 200 .

[0055] In some embodiments, the temperature of the reaction chamber is controlled at 1050° C. to 1200° C., the pressure is controlled at 100 torr to 600 torr, N source and Ga source are introduced, and a non-doped GaN layer with a thickness of 1 μm to 5 μm is grown.

[0056] S23 , depositing the N-type GaN layer 400 on the undoped GaN layer 300 .

[0057] In some embodiments, the temperature of the reaction chamber is controlled at 1050° C. to 1200° C., the pressure is controlled at 100 torr to 600 torr, and an N source, a Ga source, and a Si source are introduced to grow the N-type GaN layer.

[0058] S24 , depositing the stress release layer 500 on the N-type GaN layer 400 .

[0059] In some embodiments, the temperature of the reaction chamber is controlled at 700° C. to 900° C., the pressure is controlled at 50 torr to 600 torr, N source, Ga source, and In source are introduced, and a periodic structure of alternating InGaN layers and GaN layers is grown as a stress release layer.

[0060] S25 , depositing the multi-quantum well layer 600 on the stress release layer 500 .

[0061] In some embodiments, the multi-quantum well light-emitting layer is an alternately stacked InGaN quantum well layer and an AlGaN quantum barrier layer, with a stacking period number of 1 to 20. The growth temperature of the InGaN quantum well layer is 790°C to 810°C, the thickness is 2nm to 5nm, and the growth pressure is 50torr to 300torr; the growth temperature of the AlGaN quantum barrier layer is 800°C to 900°C, the thickness is 5nm to 15nm, and the growth pressure is 50torr to 300torr.

[0062] S26, depositing the electron blocking layer 700 on the multi-quantum well layer 600;

[0063] In some embodiments, the temperature of the reaction chamber is controlled at 900° C. to 1000° C., the pressure is controlled at 100 torr to 300 torr, N source, Al source, Ga source, and In source are introduced to grow an AlInGaN electron blocking layer with a thickness of 10 nm to 40 nm.

[0064] S27 , depositing the P-type GaN layer 800 on the electron blocking layer 700 .

[0065] In some embodiments, the temperature of the reaction chamber is controlled at 900° C. to 1050° C., the pressure is controlled at 100 torr to 600 torr, and an N source, a Mg source, and a Ga source are introduced to grow the P-type GaN layer.

[0066] Correspondingly, the present invention also provides an LED, i.e., a light emitting diode, a solid-state semiconductor device that can convert electrical energy into visible light, and the LED includes the above-mentioned light emitting diode epitaxial wafer. Specifically, the LED includes a light emitting diode chip. The light emitting diode epitaxial wafer is the basic material for the manufacture of light emitting diode chips, and the quality and characteristics of the light emitting diode epitaxial wafer directly affect the performance and output of the final light emitting diode chip. The light emitting diode chip is the core part of the LED, which determines the key characteristics of the LED such as luminous efficiency, wavelength, and chromaticity. Therefore, in the development of the LED industry, improving the quality and processing accuracy of the light emitting diode epitaxial wafer and optimizing the chip manufacturing process are of great significance to improving the performance and application range of the LED. The light emitting diode epitaxial wafer provided by the present invention can improve the integrity of laser peeling and the manufacturing yield of the final light emitting diode chip.

[0067] The present invention is further described below with specific embodiments:

[0068] Example 1

[0069] This embodiment provides a light-emitting diode epitaxial wafer, comprising a substrate, on which a buffer layer, a non-doped GaN layer, an N-type GaN layer, a stress release layer, a multi-quantum well layer, an electron blocking layer, and a P-type GaN layer are sequentially provided;

[0070] The buffer layer includes three groups of composite layers, and the composite layers include GaN layers, AlGaN layers and InGaN layers stacked in sequence. The thickness of the GaN layer is 1.5 nm, the thickness of the AlGaN layer is 1.5 nm, and the thickness of the InGaN layer is 1.5 nm.

[0071] Example 2

[0072] This embodiment provides a light-emitting diode epitaxial wafer, comprising a substrate, on which a buffer layer, a non-doped GaN layer, an N-type GaN layer, a stress release layer, a multi-quantum well layer, an electron blocking layer, and a P-type GaN layer are sequentially provided;

[0073] The buffer layer includes three groups of composite layers, and the composite layers include GaN layers, AlGaN layers and InGaN layers stacked in sequence. The thickness of the GaN layer is 1.5 nm, the thickness of the AlGaN layer is 1.5 nm, and the thickness of the InGaN layer is 0.5 nm.

[0074] Example 3

[0075] This embodiment provides a light-emitting diode epitaxial wafer, comprising a substrate, on which a buffer layer, a non-doped GaN layer, an N-type GaN layer, a stress release layer, a multi-quantum well layer, an electron blocking layer, and a P-type GaN layer are sequentially provided;

[0076] The buffer layer includes three groups of composite layers, and the composite layers include GaN layers, AlGaN layers and InGaN layers stacked in sequence. The thickness of the GaN layer is 1.5 nm, the thickness of the AlGaN layer is 1.5 nm, and the thickness of the InGaN layer is 1 nm.

[0077] Example 4

[0078] This embodiment provides a light-emitting diode epitaxial wafer, comprising a substrate, on which a buffer layer, a non-doped GaN layer, an N-type GaN layer, a stress release layer, a multi-quantum well layer, an electron blocking layer, and a P-type GaN layer are sequentially provided;

[0079] The buffer layer includes three groups of composite layers, and the composite layers include GaN layers, AlGaN layers and InGaN layers stacked in sequence. The thickness of the GaN layer is 1.5 nm, the thickness of the AlGaN layer is 1.5 nm, and the thickness of the InGaN layer is 2 nm.

[0080] Example 5

[0081] This embodiment provides a light-emitting diode epitaxial wafer, comprising a substrate, on which a buffer layer, a non-doped GaN layer, an N-type GaN layer, a stress release layer, a multi-quantum well layer, an electron blocking layer, and a P-type GaN layer are sequentially provided;

[0082] The buffer layer includes three groups of composite layers, and the composite layers include GaN layers, AlGaN layers and InGaN layers stacked in sequence. The thickness of the GaN layer is 1.5 nm, the thickness of the AlGaN layer is 1.5 nm, and the thickness of the InGaN layer is 2.5 nm.

[0083] Example 6

[0084] This embodiment provides a light-emitting diode epitaxial wafer, comprising a substrate, on which a buffer layer, a non-doped GaN layer, an N-type GaN layer, a stress release layer, a multi-quantum well layer, an electron blocking layer, and a P-type GaN layer are sequentially provided;

[0085] The buffer layer includes three groups of composite layers, and the composite layers include GaN layers, AlGaN layers and InGaN layers stacked in sequence. The thickness of the GaN layer is 0.5 nm, the thickness of the AlGaN layer is 1.5 nm, and the thickness of the InGaN layer is 1.5 nm.

[0086] Example 7

[0087] This embodiment provides a light-emitting diode epitaxial wafer, comprising a substrate, on which a buffer layer, a non-doped GaN layer, an N-type GaN layer, a stress release layer, a multi-quantum well layer, an electron blocking layer, and a P-type GaN layer are sequentially provided;

[0088] The buffer layer includes three groups of composite layers, and the composite layers include a GaN layer, an AlGaN layer and an InGaN layer stacked in sequence. The thickness of the GaN layer is 1 nm, the thickness of the AlGaN layer is 1.5 nm, and the thickness of the InGaN layer is 1.5 nm.

[0089] Example 8

[0090] This embodiment provides a light-emitting diode epitaxial wafer, comprising a substrate, on which a buffer layer, a non-doped GaN layer, an N-type GaN layer, a stress release layer, a multi-quantum well layer, an electron blocking layer, and a P-type GaN layer are sequentially provided;

[0091] The buffer layer includes three groups of composite layers, and the composite layers include a GaN layer, an AlGaN layer and an InGaN layer stacked in sequence. The thickness of the GaN layer is 2nm, the thickness of the AlGaN layer is 1.5nm, and the thickness of the InGaN layer is 1.5nm.

[0092] Example 9

[0093] This embodiment provides a light-emitting diode epitaxial wafer, comprising a substrate, on which a buffer layer, a non-doped GaN layer, an N-type GaN layer, a stress release layer, a multi-quantum well layer, an electron blocking layer, and a P-type GaN layer are sequentially provided;

[0094] The buffer layer includes three groups of composite layers, and the composite layers include GaN layers, AlGaN layers and InGaN layers stacked in sequence. The thickness of the GaN layer is 2.5 nm, the thickness of the AlGaN layer is 1.5 nm, and the thickness of the InGaN layer is 1.5 nm.

[0095] Example 10

[0096] This embodiment provides a light-emitting diode epitaxial wafer, comprising a substrate, on which a buffer layer, a non-doped GaN layer, an N-type GaN layer, a stress release layer, a multi-quantum well layer, an electron blocking layer, and a P-type GaN layer are sequentially provided;

[0097] The buffer layer includes three groups of composite layers, and the composite layers include GaN layers, AlGaN layers and InGaN layers stacked in sequence. The thickness of the GaN layer is 1.5 nm, the thickness of the AlGaN layer is 0.5 nm, and the thickness of the InGaN layer is 1.5 nm.

[0098] Embodiment 11

[0099] This embodiment provides a light-emitting diode epitaxial wafer, comprising a substrate, on which a buffer layer, a non-doped GaN layer, an N-type GaN layer, a stress release layer, a multi-quantum well layer, an electron blocking layer, and a P-type GaN layer are sequentially provided;

[0100] The buffer layer includes three groups of composite layers, and the composite layers include a GaN layer, an AlGaN layer and an InGaN layer stacked in sequence. The thickness of the GaN layer is 1.5 nm, the thickness of the AlGaN layer is 1 nm, and the thickness of the InGaN layer is 1.5 nm.

[0101] Example 12

[0102] This embodiment provides a light-emitting diode epitaxial wafer, comprising a substrate, on which a buffer layer, a non-doped GaN layer, an N-type GaN layer, a stress release layer, a multi-quantum well layer, an electron blocking layer, and a P-type GaN layer are sequentially provided;

[0103] The buffer layer includes three groups of composite layers, and the composite layers include GaN layers, AlGaN layers and InGaN layers stacked in sequence. The thickness of the GaN layer is 1.5 nm, the thickness of the AlGaN layer is 2 nm, and the thickness of the InGaN layer is 1.5 nm.

[0104] Example 13

[0105] This embodiment provides a light-emitting diode epitaxial wafer, comprising a substrate, on which a buffer layer, a non-doped GaN layer, an N-type GaN layer, a stress release layer, a multi-quantum well layer, an electron blocking layer, and a P-type GaN layer are sequentially provided;

[0106] The buffer layer includes three groups of composite layers, and the composite layers include GaN layers, AlGaN layers and InGaN layers stacked in sequence. The thickness of the GaN layer is 1.5 nm, the thickness of the AlGaN layer is 2.5 nm, and the thickness of the InGaN layer is 1.5 nm.

[0107] Embodiment 14

[0108] This embodiment provides a light-emitting diode epitaxial wafer, comprising a substrate, on which a buffer layer, a non-doped GaN layer, an N-type GaN layer, a stress release layer, a multi-quantum well layer, an electron blocking layer, and a P-type GaN layer are sequentially provided;

[0109] The buffer layer includes a group of composite layers, and the composite layer includes a GaN layer, an AlGaN layer and an InGaN layer stacked in sequence. The thickness of the GaN layer is 1.5 nm, the thickness of the AlGaN layer is 1.5 nm, and the thickness of the InGaN layer is 1.5 nm.

[0110] Embodiment 15

[0111] This embodiment provides a light-emitting diode epitaxial wafer, comprising a substrate, on which a buffer layer, a non-doped GaN layer, an N-type GaN layer, a stress release layer, a multi-quantum well layer, an electron blocking layer, and a P-type GaN layer are sequentially provided;

[0112] The buffer layer includes 5 groups of composite layers, and the composite layers include GaN layers, AlGaN layers and InGaN layers stacked in sequence. The thickness of the GaN layer is 1.5 nm, the thickness of the AlGaN layer is 1.5 nm, and the thickness of the InGaN layer is 1.5 nm.

[0113] Example 16

[0114] This embodiment provides a light-emitting diode epitaxial wafer, comprising a substrate, on which a buffer layer, a non-doped GaN layer, an N-type GaN layer, a stress release layer, a multi-quantum well layer, an electron blocking layer, and a P-type GaN layer are sequentially provided;

[0115] The buffer layer includes 6 groups of composite layers, and the composite layers include GaN layers, AlGaN layers and InGaN layers stacked in sequence. The thickness of the GaN layer is 1.5 nm, the thickness of the AlGaN layer is 1.5 nm, and the thickness of the InGaN layer is 1.5 nm.

[0116] Embodiment 17

[0117] This embodiment provides a light-emitting diode epitaxial wafer, comprising a substrate, on which a buffer layer, a non-doped GaN layer, an N-type GaN layer, a stress release layer, a multi-quantum well layer, an electron blocking layer, and a P-type GaN layer are sequentially provided;

[0118] The buffer layer includes 7 groups of composite layers, and the composite layers include GaN layers, AlGaN layers and InGaN layers stacked in sequence. The thickness of the GaN layer is 1.5 nm, the thickness of the AlGaN layer is 1.5 nm, and the thickness of the InGaN layer is 1.5 nm.

[0119] Comparative Example 1

[0120] This comparative example provides a light emitting diode epitaxial wafer, which is different from the other embodiment 1 in that its buffer layer is an AlN layer with a thickness of 10 nm, and the rest is the same as the embodiment 1.

[0121] The light emitting diode epitaxial wafers prepared in Example 10 and Comparative Example 1 were prepared into 38mil×38mil chips using the same chip process conditions. 300 LED chips were respectively extracted and tested at a current of 350mA. The specific test results are shown in Table 1.

[0122] Table 1 Performance test results of LEDs obtained in Example 17 and Comparative Example 1

[0123]

[0124] In the test results, the void ratio refers to the area ratio of the holes on the wafer after peeling, which can be obtained by AOI equipment detection. The higher the value, the better the peeling integrity. From the above results, it can be seen that the light-emitting diode epitaxial wafer provided by the present invention is conducive to improving the integrity of laser peeling and the yield of the final chip.

[0125] In the description of this specification, the description with reference to the terms "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0126] The above is a preferred embodiment of the invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the invention. These improvements and modifications are also considered to be within the scope of protection of the invention.

Claims

1. A light emitting diode epitaxial wafer, characterized in that: It comprises a substrate, on which a buffer layer, a non-doped GaN layer, an N-type GaN layer, a stress release layer, a multi-quantum well layer, an electron blocking layer, and a P-type GaN layer are sequentially arranged; The buffer layer includes at least one group of composite layers, and the composite layer includes a GaN layer, an AlGaN layer and an InGaN layer stacked in sequence.

2. The light emitting diode epitaxial wafer according to claim 1, characterized in that: The buffer layer includes 1 to 5 groups of composite layers stacked in sequence.

3. The light emitting diode epitaxial wafer according to claim 1, characterized in that: The thickness of the GaN layer is 0.1 nm to 3 nm.

4. The light emitting diode epitaxial wafer according to claim 1, characterized in that: The thickness of the AlGaN layer is 0.1 nm to 3 nm.

5. The light emitting diode epitaxial wafer according to claim 1, characterized in that: The thickness of the InGaN layer is 0.1 nm to 3 nm.

6. The light emitting diode epitaxial wafer according to claim 1, characterized in that: The thickness of the buffer layer is 3nm-40nm.

7. A method for preparing a light emitting diode epitaxial wafer according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. providing a substrate; S2, depositing a buffer layer, an undoped GaN layer, an N-type GaN layer, a stress release layer, a multi-quantum well layer, an electron blocking layer, and a P-type GaN layer on the substrate in sequence; The buffer layer includes at least one group of composite layers, and the composite layer includes a GaN layer, an AlGaN layer and an InGaN layer stacked in sequence.

8. The method for preparing a light emitting diode epitaxial wafer according to claim 7, characterized in that: The growth temperature of the buffer layer is 500° C. to 800° C., and the growth pressure is 100 torr to 500 torr.

9. The method for preparing a light emitting diode epitaxial wafer according to claim 7, characterized in that: When the GaN layer is grown, a Ga source, NH3 gas, N2 gas and H2 gas are introduced; When the InGaN layer is grown, a Ga source, an In source, NH3 gas and N2 gas are introduced; When the AlGaN layer is grown, a Ga source, an Al source, NH3 gas, N2 gas and H2 gas are introduced.

10. An LED, characterized in that: The LED comprises the light emitting diode epitaxial wafer as claimed in any one of claims 1 to 6 or comprises the light emitting diode epitaxial wafer manufactured by the method for manufacturing the light emitting diode epitaxial wafer as claimed in any one of claims 7 to 9.

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