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

Abstract

The invention relates to the field of optoelectronic technology, and discloses a light-emitting diode epitaxial wafer and a preparation method thereof, and an LED chip. The light-emitting diode epitaxial wafer comprises a substrate, on which a buffer layer, an undoped GaN layer, an N-type GaN layer, a combination layer, and a P-type GaN layer are sequentially arranged; the combination layer comprises an electron consumption layer and a band layer stacked in sequence, the electron consumption layer comprises an alternately stacked Mg-doped AlGaN layer and a BN layer, the band layer comprises a sequentially stacked medium-wave layer, a short-wave layer, and a long-wave layer, the medium-wave layer comprises an alternately stacked Ga-face polarized GaN quantum barrier layer and a first InGaN quantum well layer, the short-wave layer comprises an alternately stacked N-face polarized GaN quantum barrier layer and a second InGaN quantum well layer, and the long-wave layer comprises an alternately stacked Ga-face polarized AlGaN quantum barrier layer and a third InGaN quantum well layer. The light-emitting diode epitaxial wafer provided by the invention can reduce electron overflow and weaken the QCSE in a multi-quantum well layer.

Description

Technical Field

[0001] The present 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 chip. Background Art

[0002] GaN-based materials have an inherent polarization effect, and the resulting quantum-confined Stark effect (QCSE) will cause the energy band in the multi-quantum well layer to bend, reducing the overlap of wave functions, thereby reducing the effective recombination efficiency of holes and electrons. Moreover, since electrons migrate faster and more in number than holes, electrons that have not been recombined will produce electron overflow, reducing antistatic ability and further reducing luminous efficiency. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a light emitting diode epitaxial wafer which reduces electron overflow and weakens the quantum confinement Stark effect in the multi-quantum well layer.

[0004] The technical problem to be solved by the present invention is also 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 light-emitting performance.

[0005] 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 combination layer, and a P-type GaN layer are sequentially arranged;

[0006] The combined layer includes an electron consumption layer and a band layer stacked in sequence, the electron consumption layer includes an alternately stacked Mg-doped AlGaN layer and a BN layer, the band layer includes a medium wave layer, a short wave layer and a long wave layer stacked in sequence, the medium wave layer includes an alternately stacked Ga-face polarized GaN quantum barrier layer and a first InGaN quantum well layer, the short wave layer includes an alternately stacked N-face polarized GaN quantum barrier layer and a second InGaN quantum well layer, the long wave layer includes an alternately stacked Ga-face polarized AlGaN quantum barrier layer and a third InGaN quantum well layer, the In component content of the long wave layer is greater than the In component content of the medium wave layer, and the In component content of the medium wave layer is greater than the In component content of the short wave layer.

[0007] In some embodiments, the electron consumption layer includes 3 to 6 periods of alternately stacked Mg-doped AlGaN layers and BN layers;

[0008] The thickness of the Mg-doped AlGaN layer is 3nm-5nm;

[0009] The Mg doping concentration of the Mg-doped AlGaN layer is 1×1014 atoms / cm 3 ~1×10 16 atoms / cm 3 ;

[0010] The Al component content of the Mg-doped AlGaN layer is 0.005-0.1;

[0011] The thickness of the BN layer is 3nm~5nm.

[0012] In some embodiments, the Mg doping concentration and the Al component content of the Mg doped AlGaN layer both increase along the epitaxial growth direction.

[0013] In some embodiments, the medium-wave layer includes 2 to 11 periods of alternately stacked Ga-plane polarized GaN quantum barrier layers and a first InGaN quantum well layer;

[0014] The thickness of the Ga-plane polarized GaN quantum barrier layer is 9nm-16nm;

[0015] The thickness of the first InGaN quantum well layer is 2nm~3.5nm;

[0016] The In component content of the first InGaN quantum well layer is 0.15-0.3.

[0017] In some embodiments, the short-wave layer includes 2 to 11 periods of alternately stacked N-face polarized GaN quantum barrier layers and second InGaN quantum well layers;

[0018] The thickness of the N-side polarized GaN quantum barrier layer is 3nm~3.5nm;

[0019] The thickness of the second InGaN quantum well layer is 2nm~3.5nm;

[0020] The In component content of the second InGaN quantum well layer is 0.01-0.15.

[0021] In some embodiments, the long-wave layer includes 2 to 11 periods of alternately stacked Ga-plane polarized AlGaN quantum barrier layers and a third InGaN quantum well layer;

[0022] The thickness of the Ga-plane polarized AlGaN quantum barrier layer is 4.5nm-6nm;

[0023] The Al component content of the Ga-plane polarized AlGaN quantum barrier layer is 0.005-0.1;

[0024] The Al component content of the Ga-plane polarized AlGaN quantum barrier layer decreases along the epitaxial growth direction;

[0025] The thickness of the third InGaN quantum well layer is 2nm-3.5nm;

[0026] The In component content of the third InGaN quantum well layer is 0.3-0.5.

[0027] To solve the above problems, the present invention also provides a method for preparing a light emitting diode epitaxial wafer, comprising the following steps:

[0028] S1. providing a substrate;

[0029] S2, depositing a buffer layer, a non-doped GaN layer, an N-type GaN layer, a combination layer, and a P-type GaN layer on the substrate in sequence;

[0030] The combined layer includes an electron consumption layer and a band layer stacked in sequence, the electron consumption layer includes an alternately stacked Mg-doped AlGaN layer and a BN layer, the band layer includes a medium wave layer, a short wave layer and a long wave layer stacked in sequence, the medium wave layer includes an alternately stacked Ga-face polarized GaN quantum barrier layer and a first InGaN quantum well layer, the short wave layer includes an alternately stacked N-face polarized GaN quantum barrier layer and a second InGaN quantum well layer, the long wave layer includes an alternately stacked Ga-face polarized AlGaN quantum barrier layer and a third InGaN quantum well layer, the In component content of the long wave layer is greater than the In component content of the medium wave layer, and the In component content of the medium wave layer is greater than the In component content of the short wave layer.

[0031] In some embodiments, the growth temperature of the combined layer is 780° C. to 1000° C., and the growth pressure is 100 torr to 500 torr;

[0032] In some embodiments, the growth atmosphere of the Ga-plane polarized GaN quantum barrier layer is H2 gas and NH3 gas;

[0033] The growth atmosphere of the N-face polarized GaN quantum barrier layer is N2 gas and NH3 gas;

[0034] The growth atmosphere of the Ga-plane polarized AlGaN quantum barrier layer is H2 gas and NH3 gas.

[0035] Correspondingly, the present invention further provides an LED chip, 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.

[0036] The implementation of the present invention has the following beneficial effects:

[0037] In the light-emitting diode epitaxial wafer provided by the present invention, the combined layer includes an electron consumption layer and a band layer stacked in sequence, the electron consumption layer includes an alternately stacked Mg-doped AlGaN layer and a BN layer, the band layer includes a medium-wave layer, a short-wave layer and a long-wave layer stacked in sequence, the medium-wave layer includes an alternately stacked Ga-face polarized GaN quantum barrier layer and a first InGaN quantum well layer, the short-wave layer includes an alternately stacked N-face polarized GaN quantum barrier layer and a second InGaN quantum well layer, and the long-wave layer includes an alternately stacked Ga-face polarized AlGaN quantum barrier layer and a third InGaN quantum well layer.

[0038] First, an electron consumption layer is grown before the growth band layer. The BN layer continuously distorts the penetrating dislocations of the bottom layer, reduces the extension of dislocations, and reduces the generation of piezoelectric polarization. The Mg doped in the Mg-doped AlGaN layer continuously consumes excess electrons. The AlGaN layer increases the barrier height, slows down the electron migration speed, and improves the chip's antistatic ability.

[0039] Furthermore, in the band layer, the N-face polarity and the Ga-face polarity alternate with each other, reducing the spontaneous polarization effect, reducing non-radiative recombination, and promoting the flattening of the quantum well layer energy band, and more overlapping of the electron-hole wave functions. At the same time, compared with the N-face polarity, the Ga-face polarity can effectively improve the crystal quality of the quantum well layer, reduce the incorporation of impurities, improve the clarity of the interface, reduce the risk of leakage, and improve the effective composite luminescence efficiency of the band layer.

[0040] Furthermore, the short-wave layer polarization field has the same direction as the external electric field, and the polarization field and the external electric field jointly accelerate the injection of electrons and holes into the quantum well layer, further improving the carrier injection efficiency, thereby improving the luminescence efficiency of the quantum well layer and reducing the loss of operating voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A schematic diagram of the structure of a light emitting diode epitaxial wafer provided by the present invention;

[0042] Figure 2 A schematic structural diagram of a medium-wavelength layer of a light-emitting diode epitaxial wafer provided by the present invention;

[0043] Figure 3 A schematic structural diagram of a short-wave layer of a light-emitting diode epitaxial wafer provided by the present invention;

[0044] Figure 4 This is a schematic structural diagram of the long-wave layer of the light-emitting diode epitaxial wafer provided by the present invention. DETAILED DESCRIPTION

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] To solve the above problems, the present invention provides a light emitting diode epitaxial wafer, such as Figure 1~Figure 4 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 combination layer 500, and a P-type GaN layer 600 are sequentially arranged;

[0053] The combined layer 500 includes an electron consumption layer 510 and a band layer 520 stacked in sequence, wherein the electron consumption layer 510 includes an Mg-doped AlGaN layer 511 and a BN layer 512 stacked alternately, and the band layer 520 includes a medium-wave layer 521, a short-wave layer 522 and a long-wave layer 523 stacked in sequence, wherein the medium-wave layer 521 includes a Ga-plane polarized GaN quantum barrier layer 521a and a first InGaN quantum well layer 521b stacked alternately, and the short-wave layer 522 includes alternately stacked N-face polarized GaN quantum barrier layers 522a and a second InGaN quantum well layer 522b, the long-wave layer 523 includes alternately stacked Ga-face polarized AlGaN quantum barrier layers 523a and a third InGaN quantum well layer 523b, the In component content of the long-wave layer 523 is greater than the In component content of the medium-wave layer 521, and the In component content of the medium-wave layer 521 is greater than the In component content of the short-wave layer 522.

[0054] The light-emitting diode provided by the present invention grows an electron consumption layer before growing a band layer, the BN layer continuously distorts the penetrating dislocation of the bottom layer, reduces the extension of the dislocation, and reduces the generation of piezoelectric polarization, the Mg doped in the Mg-doped AlGaN layer continuously consumes excessive electrons, the AlGaN layer increases the barrier height, slows down the electron migration speed, and improves the antistatic ability of the chip.

[0055] Then, in the band layer, the N-face polarity and the Ga-face polarity alternate with each other, reducing the spontaneous polarization effect, reducing non-radiative recombination, and promoting the flattening of the quantum well layer energy band, and more overlapping of the electron-hole wave functions. At the same time, compared with the N-face polarity, the Ga-face polarity can effectively improve the crystal quality of the quantum well layer, reduce the incorporation of impurities, improve the clarity of the interface, reduce the risk of leakage, and improve the effective composite luminescence efficiency of the band layer.

[0056] Furthermore, the short-wave layer polarization field has the same direction as the external electric field, and the polarization field and the external electric field jointly accelerate the injection of electrons and holes into the quantum well layer, further improving the carrier injection efficiency, thereby improving the luminescence efficiency of the quantum well layer and reducing the loss of operating voltage.

[0057] The specific structure of the electronic consumption layer 510 provided by the present invention is as follows:

[0058] In some embodiments, the electron consumption layer 510 includes 3 to 6 periods of alternately stacked Mg-doped AlGaN layers 511 and BN layers 512 , and exemplary numbers of periods are 3, 4, 5, and 6.

[0059] In some embodiments, the thickness of the Mg-doped AlGaN layer 511 is 3 nm to 5 nm; exemplary thicknesses of the Mg-doped AlGaN layer 511 are 3.5 nm, 4 nm, 4.5 nm, and 5 nm, but are not limited to the above examples.

[0060] In some embodiments, the Mg doping concentration of the Mg doped AlGaN layer 511 is 1×10 14 atoms / cm 3 ~1×10 16 atoms / cm 3 The exemplary Mg doping concentration of the Mg-doped AlGaN layer 511 is 5×10 14 atoms / cm 3 , 1×10 15 atoms / cm 3 , 5×10 15 atoms / cm 3, not limited to the above. Preferably, the Mg doping concentration of the Mg doped AlGaN layer 511 increases along the epitaxial growth direction; Mg doping continuously consumes excess electrons, and the AlGaN layer increases the barrier height, slows down the electron migration speed, and improves the antistatic ability of the chip.

[0061] In some embodiments, the Al component content of the Mg-doped AlGaN layer 511 is 0.005-0.1; preferably, the Al component content of the Mg-doped AlGaN layer 511 is 0.01-0.1. More preferably, the Al component content of the Mg-doped AlGaN layer 511 increases along the epitaxial growth direction. Increasing the potential barrier in stages and slowing down the electron migration speed can reduce the operating voltage and the lattice mismatch between layers, reduce the generation of defects, and thus improve the effective radiation recombination efficiency.

[0062] In some embodiments, the thickness of the BN layer 512 is 3nm to 5nm; exemplary thicknesses of the BN layer 512 are 3.5nm, 4nm, 4.5nm, and 5nm, but are not limited to the above. Before growing the band layer, the electron consumption layer is grown, and the BN layer continuously distorts the penetrating dislocations of the bottom layer, reduces the extension of the dislocations, and reduces the generation of piezoelectric polarization.

[0063] The specific structure of the band layer 520 provided by the present invention is as follows:

[0064] The In component content of the long-wave layer 523 is greater than the In component content of the medium-wave layer 521 and greater than the In component content of the short-wave layer 522. By adjusting the In component content, the emission wavelengths of the long-wave layer, the medium-wave layer, and the short-wave layer can be achieved.

[0065] In some embodiments, Figure 2 As shown, the medium wave layer 521 includes 2 to 11 periods of alternately stacked Ga-face polarized GaN quantum barrier layers 521a and first InGaN quantum well layers 521b; exemplary period numbers are 3, 4, 5, 6, 7, 8, 9, 10, and 11. The thickness of the Ga-face polarized GaN quantum barrier layer 521a is 9nm to 16nm; the exemplary thickness of the Ga-face polarized GaN quantum barrier layer 521a is 10nm, 11nm, 12nm, 13nm, 14nm, and 15nm, not limited to the above. The thickness of the first InGaN quantum well layer 521b is 2nm to 3.5nm. The exemplary thickness of the first InGaN quantum well layer 521b is 2.2nm, 2.4nm, 2.6nm, 2.8nm, 3nm, 3.2nm, and 3.4nm, not limited to the above. The In component content of the first InGaN quantum well layer 521b is 0.15-0.3. Preferably, the In component content of the first InGaN quantum well layer 521b is 0.2-0.25.

[0066] In some embodiments, Figure 3 As shown, the short-wave layer 522 includes 2 to 11 periods of alternately stacked N-face polarized GaN quantum barrier layers 522a and second InGaN quantum well layers 522b; exemplary period numbers are 3, 4, 5, 6, 7, 8, 9, 10, and 11. The thickness of the N-face polarized GaN quantum barrier layer 522a is 3nm to 3.5nm; the exemplary thickness of the N-face polarized GaN quantum barrier layer 522a is 3.1nm, 3.2nm, 3.2nm, and 3.4nm, not limited to the above. The thickness of the second InGaN quantum well layer 522b is 2nm to 3.5nm. The exemplary thickness of the second InGaN quantum well layer 522b is 2.2nm, 2.4nm, 2.6nm, 2.8nm, 3nm, 3.2nm, and 3.4nm, not limited to the above. The In component content of the second InGaN quantum well layer 522b is 0.01 to 0.15. Preferably, the In component content of the second InGaN quantum well layer 522b is 0.05-0.1.

[0067] In some embodiments, Figure 4 As shown, the long-wave layer 523 includes 2 to 11 periods of alternately stacked Ga-plane polarized AlGaN quantum barrier layers 523a and third InGaN quantum well layers 523b; exemplary period numbers are 3, 4, 5, 6, 7, 8, 9, 10, and 11. The thickness of the Ga-plane polarized AlGaN quantum barrier layer 523a is 4.5nm to 6nm; the exemplary thickness of the Ga-plane polarized AlGaN quantum barrier layer 523a is 4.8nm, 5nm, 5.2nm, 5.4nm, 5.6nm, 5.8nm, and 6nm, not limited to the above. The thickness of the third InGaN quantum well layer 523b is 2nm to 3.5nm. The exemplary thickness of the third InGaN quantum well layer 523b is 2.2nm, 2.4nm, 2.6nm, 2.8nm, 3nm, 3.2nm, and 3.4nm, not limited to the above. The In component content of the third InGaN quantum well layer 523b is 0.3-0.5. Preferably, the In component content of the third InGaN quantum well layer 523b is 0.35-0.45.

[0068] In some embodiments, the Al component content of the Ga-plane polarized AlGaN quantum barrier layer 523a is 0.005~0.1; preferably, the Al component content of the Ga-plane polarized AlGaN quantum barrier layer 523a is 0.01~0.1; more preferably, the Al component content of the Ga-plane polarized AlGaN quantum barrier layer 523a decreases along the epitaxial growth direction; this helps to reduce the stress caused by lattice mismatch.

[0069] In the above-mentioned band layer, the N-face polarity and the Ga-face polarity alternate with each other, reducing the spontaneous polarization effect, reducing non-radiative recombination, and promoting the flattening of the quantum well layer energy band, and more overlapping of the electron-hole wave functions. At the same time, compared with the N-face polarity, the Ga-face polarity can effectively improve the crystal quality of the quantum well layer, reduce the incorporation of impurities, improve the clarity of the interface, reduce the risk of leakage, and improve the effective composite luminescence efficiency of the band layer.

[0070] Furthermore, the short-wave layer polarization field has the same direction as the external electric field, and the polarization field and the external electric field jointly accelerate the injection of electrons and holes into the quantum well layer, further improving the carrier injection efficiency, thereby improving the luminescence efficiency of the quantum well layer and reducing the loss of operating voltage.

[0071] Accordingly, the present invention provides a method for preparing a light emitting diode epitaxial wafer, comprising the following steps:

[0072] S1, providing a substrate 100;

[0073] 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.

[0074] S2, sequentially depositing a buffer layer 200, a non-doped GaN layer 300, an N-type GaN layer 400, a combination layer 500, and a P-type GaN layer 600 on the substrate 100;

[0075] The combined layer 500 includes an electron consumption layer 510 and a band layer 520 stacked in sequence, wherein the electron consumption layer 510 includes an Mg-doped AlGaN layer 511 and a BN layer 512 stacked alternately, and the band layer 520 includes a medium-wave layer 521, a short-wave layer 522 and a long-wave layer 523 stacked in sequence, wherein the medium-wave layer 521 includes a Ga-plane polarized GaN quantum barrier layer 521a and a first InGaN quantum well layer 521b stacked alternately, and the short-wave layer 522 includes alternately stacked N-face polarized GaN quantum barrier layers 522a and a second InGaN quantum well layer 522b, the long-wave layer 523 includes alternately stacked Ga-face polarized AlGaN quantum barrier layers 523a and a third InGaN quantum well layer 523b, the In component content of the long-wave layer 523 is greater than the In component content of the medium-wave layer 521, and the In component content of the medium-wave layer 521 is greater than the In component content of the short-wave layer 522.

[0076] Specifically, the above step S2 specifically includes the following steps:

[0077] S21 , depositing the buffer layer 200 on the substrate 100 .

[0078] In some embodiments, the buffer layer 200 is an AlN buffer layer deposited in PVD. The AlN buffer layer provides a nucleation center with the same orientation as the substrate, releases the stress caused by the lattice mismatch between GaN and the substrate and the thermal stress caused by the mismatch of thermal expansion coefficients, provides a flat nucleation surface for further growth, reduces the contact angle of its nucleation growth, and enables the island-like grown GaN grains to be connected into a surface within a smaller thickness, thereby transforming into two-dimensional epitaxial growth.

[0079] S22 , depositing the undoped GaN layer 300 on the buffer layer 200 .

[0080] 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.

[0081] S23 , depositing the N-type GaN layer 400 on the undoped GaN layer 300 .

[0082] 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.

[0083] S24 , depositing the combined layer 500 on the N-type GaN layer 400 .

[0084] In some embodiments, the combined layer is prepared by the following method: the electron consumption layer 510 and the band layer 520 are grown in sequence.

[0085] In some embodiments, the electronic consumption layer 510 is prepared by the following method:

[0086] The temperature of the reaction chamber is controlled at 780° C. to 1000° C., the pressure is controlled at 100 torr to 500 torr, and N source, Ga source, Al source, and Mg source are introduced to grow the Mg-doped AlGaN layer 511;

[0087] The temperature of the reaction chamber is controlled at 780° C. to 1000° C., the pressure is controlled at 100 torr to 500 torr, and an N source and a B source are introduced to grow the BN layer 512;

[0088] The Mg-doped AlGaN layer 511 and the BN layer 512 are alternately grown to obtain the electron consumption layer 510 .

[0089] In some embodiments, the wavelength band layer 520 is manufactured by the following method: a medium wavelength layer 521, a short wavelength layer 522 and a long wavelength layer 523 are grown in sequence.

[0090] In some embodiments, the medium wave layer 521 is made by the following method:

[0091] The temperature of the reaction chamber is controlled at 780° C. to 1000° C., the pressure is controlled at 100 torr to 500 torr, the growth atmosphere is H2 gas and NH3 gas, N source and Ga source are introduced, and the Ga-plane polarized GaN quantum barrier layer 521a is grown;

[0092] The temperature of the reaction chamber is controlled at 780° C. to 1000° C., the pressure is controlled at 100 torr to 500 torr, and N source, Ga source, and In source are introduced to grow the first InGaN quantum well layer 521 b;

[0093] The Ga-plane polarized GaN quantum barrier layer 521 a and the first InGaN quantum well layer 521 b are grown alternately to obtain the medium-wave layer 521 .

[0094] In some embodiments, the short-wave layer 522 is made by the following method:

[0095] The temperature of the reaction chamber is controlled at 780° C. to 1000° C., the pressure is controlled at 100 torr to 500 torr, the growth atmosphere is N2 gas and NH3 gas, N source and Ga source are introduced, and the N-face polarized GaN quantum barrier layer 522a is grown;

[0096] The temperature of the reaction chamber is controlled at 780° C. to 1000° C., the pressure is controlled at 100 torr to 500 torr, and N source, Ga source, and In source are introduced to grow a second InGaN quantum well layer 522 b ;

[0097] The N-face polarized GaN quantum barrier layer 522 a and the second InGaN quantum well layer 522 b are grown alternately to obtain the short-wave layer 522 .

[0098] In some embodiments, the long-wave layer 523 is made by the following method:

[0099] The temperature of the reaction chamber is controlled at 780° C. to 1000° C., the pressure is controlled at 100 torr to 500 torr, the growth atmosphere is H2 gas and NH3 gas, N source, Ga source and Al source are introduced, and the Ga-plane polarized AlGaN quantum barrier layer 523a is grown;

[0100] The temperature of the reaction chamber is controlled at 780° C. to 1000° C., the pressure is controlled at 100 torr to 500 torr, and N source, Ga source, and In source are introduced to grow the third InGaN quantum well layer 523 b ;

[0101] The Ga-plane polarized AlGaN quantum barrier layer 523 a and the third InGaN quantum well layer 523 b are grown alternately to obtain the long-wave layer 523 .

[0102] In some embodiments, the growth atmosphere of the Ga-face polarized GaN quantum barrier layer 521a is H2 gas and NH3 gas; under this growth atmosphere, Ga-face polarized growth can be achieved;

[0103] The growth atmosphere of the N-face polarized GaN quantum barrier layer 522a is N2 gas and NH3 gas; in this growth atmosphere, N-face polarized growth can be achieved;

[0104] The growth atmosphere of the Ga-face polarized AlGaN quantum barrier layer 523 a is H 2 gas and NH 3 gas; under this growth atmosphere, Ga-face polarized growth can be achieved.

[0105] S25 , depositing the P-type GaN layer 600 on the combined layer 500 .

[0106] 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.

[0107] Correspondingly, the present invention also provides an LED chip, i.e., a light-emitting diode chip, which includes the above-mentioned light-emitting diode epitaxial wafer. 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 the 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.

[0108] The present invention is further described below with specific embodiments:

[0109] Example 1

[0110] 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 combination layer, and a P-type GaN layer are sequentially provided;

[0111] The combined layer includes an electron consumption layer and a band layer stacked in sequence, the electron consumption layer includes an alternately stacked Mg-doped AlGaN layer and a BN layer, the band layer includes a medium wave layer, a short wave layer and a long wave layer stacked in sequence, the medium wave layer includes an alternately stacked Ga-face polarized GaN quantum barrier layer and a first InGaN quantum well layer, the short wave layer includes an alternately stacked N-face polarized GaN quantum barrier layer and a second InGaN quantum well layer, the long wave layer includes an alternately stacked Ga-face polarized AlGaN quantum barrier layer and a third InGaN quantum well layer, and the In component content of the long wave layer is greater than the In component content of the medium wave layer and greater than the In component content of the short wave layer.

[0112] The electron consumption layer includes 4 periods of alternately stacked Mg-doped AlGaN layers and BN layers; the thickness of the Mg-doped AlGaN layer is 4 nm, and the Mg doping concentration is 1×10 15 atoms / cm 3 The Al component content increases from 0.01 to 0.1 along the epitaxial growth direction; the thickness of the BN layer is 4 nm.

[0113] The medium wave layer includes 8 periods of alternately stacked Ga-plane polarized GaN quantum barrier layers and a first InGaN quantum well layer; the thickness of the Ga-plane polarized GaN quantum barrier layer is 13 nm; and the thickness of the first InGaN quantum well layer is 3 nm.

[0114] The short-wave layer includes 8 periods of alternately stacked N-face polarized GaN quantum barrier layers and second InGaN quantum well layers; the thickness of the N-face polarized GaN quantum barrier layers is 3.2 nm; and the thickness of the second InGaN quantum well layer is 3 nm.

[0115] The long-wave layer includes 8 periods of alternately stacked Ga-plane polarized AlGaN quantum barrier layers and a third InGaN quantum well layer; the thickness of the Ga-plane polarized AlGaN quantum barrier layer is 5nm, and the Al component content decreases from 0.1 to 0.01 along the epitaxial growth direction; the thickness of the third InGaN quantum well layer is 3nm.

[0116] Example 2

[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 combination layer, and a P-type GaN layer are sequentially provided;

[0118] The combined layer includes an electron consumption layer and a band layer stacked in sequence, the electron consumption layer includes an alternately stacked Mg-doped AlGaN layer and a BN layer, the band layer includes a medium wave layer, a short wave layer and a long wave layer stacked in sequence, the medium wave layer includes an alternately stacked Ga-face polarized GaN quantum barrier layer and a first InGaN quantum well layer, the short wave layer includes an alternately stacked N-face polarized GaN quantum barrier layer and a second InGaN quantum well layer, the long wave layer includes an alternately stacked Ga-face polarized AlGaN quantum barrier layer and a third InGaN quantum well layer, and the In component content of the long wave layer is greater than the In component content of the medium wave layer and greater than the In component content of the short wave layer.

[0119] The electron consumption layer includes 4 periods of alternately stacked Mg-doped AlGaN layers and BN layers; the thickness of the Mg-doped AlGaN layer is 3.2 nm, and the Mg doping concentration is 1×10 15 atoms / cm 3 The Al component content increases from 0.01 to 0.1 along the epitaxial growth direction; the thickness of the BN layer is 4.5 nm.

[0120] The medium-wave layer includes 8 periods of alternately stacked Ga-plane polarized GaN quantum barrier layers and a first InGaN quantum well layer; the thickness of the Ga-plane polarized GaN quantum barrier layer is 9.1 nm; and the thickness of the first InGaN quantum well layer is 3.4 nm.

[0121] The short-wave layer includes 8 periods of alternately stacked N-face polarized GaN quantum barrier layers and second InGaN quantum well layers; the thickness of the N-face polarized GaN quantum barrier layers is 3.4 nm; and the thickness of the second InGaN quantum well layers is 3.3 nm.

[0122] The long-wave layer includes 8 periods of alternately stacked Ga-plane polarized AlGaN quantum barrier layers and a third InGaN quantum well layer; the thickness of the Ga-plane polarized AlGaN quantum barrier layer is 4.7nm, and the Al component content decreases from 0.1 to 0.01 along the epitaxial growth direction; the thickness of the third InGaN quantum well layer is 3.4nm.

[0123] Example 3

[0124] 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 combination layer, and a P-type GaN layer are sequentially provided;

[0125] The combined layer includes an electron consumption layer and a band layer stacked in sequence, the electron consumption layer includes an alternately stacked Mg-doped AlGaN layer and a BN layer, the band layer includes a medium wave layer, a short wave layer and a long wave layer stacked in sequence, the medium wave layer includes an alternately stacked Ga-face polarized GaN quantum barrier layer and a first InGaN quantum well layer, the short wave layer includes an alternately stacked N-face polarized GaN quantum barrier layer and a second InGaN quantum well layer, the long wave layer includes an alternately stacked Ga-face polarized AlGaN quantum barrier layer and a third InGaN quantum well layer, and the In component content of the long wave layer is greater than the In component content of the medium wave layer and greater than the In component content of the short wave layer.

[0126] The electron consumption layer includes 4 periods of alternately stacked Mg-doped AlGaN layers and BN layers; the thickness of the Mg-doped AlGaN layer is 4.7 nm, and the Mg doping concentration is 1×10 15 atoms / cm 3 The Al component content increases from 0.01 to 0.1 along the epitaxial growth direction; the thickness of the BN layer is 3.7 nm.

[0127] The medium-wave layer includes 8 periods of alternately stacked Ga-plane polarized GaN quantum barrier layers and a first InGaN quantum well layer; the thickness of the Ga-plane polarized GaN quantum barrier layer is 15.7 nm; and the thickness of the first InGaN quantum well layer is 2.1 nm.

[0128] The short-wave layer includes 8 periods of alternately stacked N-face polarized GaN quantum barrier layers and second InGaN quantum well layers; the thickness of the N-face polarized GaN quantum barrier layers is 3.1 nm; and the thickness of the second InGaN quantum well layer is 2.2 nm.

[0129] The long-wave layer includes 8 periods of alternately stacked Ga-plane polarized AlGaN quantum barrier layers and a third InGaN quantum well layer; the thickness of the Ga-plane polarized AlGaN quantum barrier layer is 5.8nm, and the Al component content decreases from 0.1 to 0.01 along the epitaxial growth direction; the thickness of the third InGaN quantum well layer is 2.4nm.

[0130] Comparative Example 1

[0131] This comparative example provides a light emitting diode epitaxial wafer, which is different from Example 1 in that its combined layer does not include an electron consumption layer, and the rest is the same as Example 1.

[0132] Comparative Example 2

[0133] This comparative example provides a light-emitting diode epitaxial wafer, which is different from Example 1 in that: the combined layer includes an electron-consuming layer and a multi-quantum well layer stacked in sequence, the electron-consuming layer includes an alternately stacked Mg-doped AlGaN layer and a BN layer, and the multi-quantum well layer includes an alternately stacked GaN quantum barrier layer and an InGaN quantum well layer, and the rest is the same as Example 1.

[0134] The light-emitting diode epitaxial wafers prepared in Examples 1 to 3 and Comparative Examples 1 and 2 were used to prepare LED chips with a size of 38 mil×38 mil using the same chip process conditions. 300 LED chips were respectively extracted and tested at a current of 350 mA. Based on Comparative Example 2, the luminous efficiency improvement rate and ESD (electrostatic discharge) improvement of the remaining examples and comparative examples were calculated. The specific test results are shown in Table 1.

[0135] Table 1 Performance test results of LED chips prepared in Examples 1 to 3 and Comparative Examples 1 and 2

[0136]

[0137] In the light-emitting diode epitaxial wafer provided by the present invention, the combined layer includes an electron consumption layer and a band layer stacked in sequence, the electron consumption layer includes an alternately stacked Mg-doped AlGaN layer and a BN layer, the band layer includes a medium-wave layer, a short-wave layer and a long-wave layer stacked in sequence, the medium-wave layer includes an alternately stacked Ga-face polarized GaN quantum barrier layer and a first InGaN quantum well layer, the short-wave layer includes an alternately stacked N-face polarized GaN quantum barrier layer and a second InGaN quantum well layer, and the long-wave layer includes an alternately stacked Ga-face polarized AlGaN quantum barrier layer and a third InGaN quantum well layer.

[0138] First, an electron consumption layer is grown before the growth band layer. The BN layer continuously distorts the penetrating dislocations of the bottom layer, reduces the extension of dislocations, and reduces the generation of piezoelectric polarization. The Mg doped in the Mg-doped AlGaN layer continuously consumes excess electrons. The AlGaN layer increases the barrier height, slows down the electron migration speed, and improves the chip's antistatic ability.

[0139] Furthermore, in the band layer, the N-face polarity and the Ga-face polarity alternate with each other, reducing the spontaneous polarization effect, reducing non-radiative recombination, and promoting the flattening of the quantum well layer energy band, and more overlapping of the electron-hole wave functions. At the same time, compared with the N-face polarity, the Ga-face polarity can effectively improve the crystal quality of the quantum well layer, reduce the incorporation of impurities, improve the clarity of the interface, reduce the risk of leakage, and improve the effective composite luminescence efficiency of the band layer.

[0140] Furthermore, the short-wave layer polarization field has the same direction as the external electric field, and the polarization field and the external electric field jointly accelerate the injection of electrons and holes into the quantum well layer, further improving the carrier injection efficiency, thereby improving the luminescence efficiency of the quantum well layer and reducing the loss of operating voltage.

[0141] 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.

[0142] 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 combination layer, and a P-type GaN layer are sequentially arranged; The combined layer includes an electron consumption layer and a band layer stacked in sequence, the electron consumption layer includes an alternately stacked Mg-doped AlGaN layer and a BN layer, the band layer includes a medium wave layer, a short wave layer and a long wave layer stacked in sequence, the medium wave layer includes an alternately stacked Ga-face polarized GaN quantum barrier layer and a first InGaN quantum well layer, the short wave layer includes an alternately stacked N-face polarized GaN quantum barrier layer and a second InGaN quantum well layer, the long wave layer includes an alternately stacked Ga-face polarized AlGaN quantum barrier layer and a third InGaN quantum well layer, the In component content of the long wave layer is greater than the In component content of the medium wave layer, and the In component content of the medium wave layer is greater than the In component content of the short wave layer.

2. The light emitting diode epitaxial wafer according to claim 1, characterized in that: The electron consumption layer includes 3 to 6 periods of alternately stacked Mg-doped AlGaN layers and BN layers; The thickness of the Mg-doped AlGaN layer is 3nm-5nm; The Mg doping concentration of the Mg-doped AlGaN layer is 1×10 14 atoms / cm 3 ~1×10 16 atoms / cm 3 ; The Al component content of the Mg-doped AlGaN layer is 0.005-0.1; The thickness of the BN layer is 3nm~5nm.

3. The light emitting diode epitaxial wafer according to claim 2, characterized in that: The Mg doping concentration and Al component content of the Mg doped AlGaN layer both increase along the epitaxial growth direction.

4. The light emitting diode epitaxial wafer according to claim 1, characterized in that: The medium-wave layer includes 2 to 11 periods of alternately stacked Ga-plane polarized GaN quantum barrier layers and a first InGaN quantum well layer; The thickness of the Ga-plane polarized GaN quantum barrier layer is 9nm-16nm; The thickness of the first InGaN quantum well layer is 2nm~3.5nm; The In component content of the first InGaN quantum well layer is 0.15-0.

3.

5. The light emitting diode epitaxial wafer according to claim 1, characterized in that: The short-wave layer includes 2 to 11 periods of alternately stacked N-face polarized GaN quantum barrier layers and second InGaN quantum well layers; The thickness of the N-side polarized GaN quantum barrier layer is 3nm~3.5nm; The thickness of the second InGaN quantum well layer is 2nm~3.5nm; The In component content of the second InGaN quantum well layer is 0.01-0.

15.

6. The light emitting diode epitaxial wafer according to claim 1, characterized in that: The long-wave layer includes 2 to 11 periods of alternately stacked Ga-plane polarized AlGaN quantum barrier layers and a third InGaN quantum well layer; The thickness of the Ga-plane polarized AlGaN quantum barrier layer is 4.5nm-6nm; The Al component content of the Ga-plane polarized AlGaN quantum barrier layer is 0.005-0.1; The Al component content of the Ga-plane polarized AlGaN quantum barrier layer decreases along the epitaxial growth direction; The thickness of the third InGaN quantum well layer is 2nm-3.5nm; The In component content of the third InGaN quantum well layer is 0.3-0.

5.

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, a non-doped GaN layer, an N-type GaN layer, a combination layer, and a P-type GaN layer on the substrate in sequence; The combined layer includes an electron consumption layer and a band layer stacked in sequence, the electron consumption layer includes an alternately stacked Mg-doped AlGaN layer and a BN layer, the band layer includes a medium wave layer, a short wave layer and a long wave layer stacked in sequence, the medium wave layer includes an alternately stacked Ga-face polarized GaN quantum barrier layer and a first InGaN quantum well layer, the short wave layer includes an alternately stacked N-face polarized GaN quantum barrier layer and a second InGaN quantum well layer, the long wave layer includes an alternately stacked Ga-face polarized AlGaN quantum barrier layer and a third InGaN quantum well layer, the In component content of the long wave layer is greater than the In component content of the medium wave layer, and the In component content of the medium wave layer is greater than the In component content of the short wave layer.

8. The method for preparing a light emitting diode epitaxial wafer according to claim 7, characterized in that: The growth temperature of the combined layer is 780° C. to 1000° 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: The growth atmosphere of the Ga-plane polarized GaN quantum barrier layer is H2 gas and NH3 gas; The growth atmosphere of the N-face polarized GaN quantum barrier layer is N2 gas and NH3 gas; The growth atmosphere of the Ga-plane polarized AlGaN quantum barrier layer is H2 gas and NH3 gas.

10. An LED chip, characterized in that: The LED chip comprises the light emitting diode epitaxial wafer as described in any one of claims 1 to 6.

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