Light emitting diode with composite p-type layer and method of making the same

Abstract

The present disclosure provides a light emitting diode with a composite P-type layer and a preparation method thereof, and belongs to the field of light emitting diodes. The light emitting diode comprises a substrate, and an N-type layer, a multi-quantum well layer and a composite P-type layer sequentially grown on one side of the substrate. The composite P-type layer comprises a first layer, an intermediate layer and a second layer sequentially grown; the first layer and the second layer are non-doped N-type Al x Ga 1‑x N layers (0 < x < 1), non-doped N-type In y Ga 1‑y N layers (0 < y < 1) or periodically stacked non-doped Al x Ga 1‑x N / In y Ga 1‑y N layers (0 < x < 1 and 0 < y < 1); the intermediate layer is a Mg-doped GaN layer. The present disclosure can effectively improve the light emitting efficiency of the light emitting diode.

Description

Technical Field

[0001] The present disclosure belongs to the field of light-emitting diodes, and in particular relates to a light-emitting diode with a composite P-type layer and a preparation method thereof. Background Art

[0002] Light-emitting diodes (LEDs) are a common type of light-emitting electronic device that is widely used in various fields.

[0003] In related technologies, GaN, a typical representative of III-V compound semiconductors, is a third-generation semiconductor material, following Si and GaAs. It possesses excellent properties such as a wide bandgap, a strong breakdown electric field, high electron mobility, and excellent thermal stability. The epitaxial layers of GaN-based light-emitting diodes primarily consist of an N-type layer, a multi-quantum well layer, and a P-type layer.

[0004] However, Mg is currently the most commonly used hole dopant. Since Mg is an acceptor element, its activation efficiency is very low, resulting in a large difference between the hole concentration obtained by P-type doping and the electron concentration obtained by N-type doping, resulting in a low hole mobility in the P-type layer and a low luminous efficiency of the light-emitting diode. Summary of the Invention

[0005] The present disclosure provides a light-emitting diode with a composite P-type layer and a method for manufacturing the same, which can effectively improve the light-emitting efficiency of the light-emitting diode. The technical solution is as follows:

[0006] In one aspect, an embodiment of the present disclosure provides a light emitting diode having a composite P-type layer, comprising:

[0007] A substrate, and an N-type layer, a multi-quantum well layer, and a composite P-type layer sequentially grown on one side of the substrate;

[0008] The composite P-type layer includes a first layer, an intermediate layer, and a second layer grown sequentially;

[0009] The first layer is non-doped N-type Al a Ga 1-a N layer, undoped N-type In b Ga 1-b N layer or periodically stacked undoped Al c Ga 1-c N / In d Ga 1-d Any of the N layers, 0<a<1, 0<b<1, 0<c<1, 0<d<1;

[0010] The second layer is non-doped N-type Al e Ga 1-e N layer, undoped N-type In f Ga1-f N layer or periodically stacked undoped Al g Ga 1-g N / In h Ga 1-h Any of the N layers, 0<e<1, 0<f<1, 0<g<1, 0<h<1;

[0011] The middle layer is a Mg-doped GaN layer.

[0012] In one implementation of the present disclosure, when the first layer is non-doped N-type Al a Ga 1-a N layer or undoped N-type In b Ga 1-b N layer, and when the second layer is non-doped N-type Al e Ga 1-e N layer or undoped N-type In f Ga 1-f When there are N layers, the thickness of the first layer and the second layer are both 1 to 10 nm;

[0013] When the first layer is non-doped Al c Ga 1-c N / In d Ga 1-d N layer, and when the second layer is non-doped Al g Ga 1-g N / In h Ga 1-h When there are N layers, the thickness of the first layer and the second layer are both 1 to 3 nm;

[0014] The thickness of the intermediate layer is 95-730 nm.

[0015] In an implementation of the present disclosure, the interface roughness between the first layer and the second layer is 15-24.

[0016] In an implementation of the present disclosure, the first layer, the middle layer, and the second layer are periodically stacked, with the number of periods being 1 to 6.

[0017] In one implementation of the present disclosure, the thickness of the first layer and the second layer are both 1 to 2 nm;

[0018] The thickness of the intermediate layer is 15 to 120 nm.

[0019] On the other hand, an embodiment of the present disclosure provides a method for preparing a light-emitting diode having a composite P-type layer, comprising:

[0020] providing a substrate;

[0021] sequentially growing an N-type layer, a multi-quantum well layer, and a composite P-type layer on one side of the substrate;

[0022] The composite P-type layer is grown by the following method:

[0023] The first layer, the middle layer and the second layer are grown in sequence, wherein:

[0024] The first layer is non-doped N-type Al a Ga 1-a N layer, undoped N-type In b Ga 1-b N layer or periodically stacked undoped Al c Ga 1-c N / In d Ga 1-d Any of the N layers, 0<a<1, 0<b<1, 0<c<1, 0<d<1;

[0025] The second layer is non-doped N-type Al e Ga 1-e N layer, undoped N-type In f Ga 1-f N layer or periodically stacked undoped Al g Ga 1-g N / In h Ga 1-h Any of the N layers, 0<e<1, 0<f<1, 0<g<1, 0<h<1;

[0026] The middle layer is a Mg-doped GaN layer.

[0027] In one implementation of the present disclosure, growing the first layer and the second layer includes:

[0028] When the first layer is non-doped N-type Al a Ga 1-a N layer or undoped N-type In b Ga 1-b N layer, and when the second layer is non-doped N-type Al e Ga 1-e N layer or undoped N-type In f Ga 1-f In the case of an N layer, the growth temperature of the first layer and the second layer is 800-980° C., the growth time is 15-300 s, and the growth thickness is 1-10 nm.

[0029] In one implementation of the present disclosure, growing the first layer and the second layer includes:

[0030] When the first layer is non-doped Alc Ga 1-c N / In d Ga 1-d N layer, and when the second layer is an undoped Al g Ga 1-g N / In h Ga 1-h N layer, the growth temperature of the first layer and the second layer is 800-980℃, the growth time is not more than 120s, the growth thickness is 1-3nm, and the cycle number is 1-3.

[0031] In an implementation form of the present disclosure, growing the intermediate layer comprises:

[0032] The growth temperature is 800-980℃, the growth time is 5-600s, the growth thickness is 95-730nm, and the growth pressure is 100-500torr.

[0033] In an implementation form of the present disclosure, the preparation method further comprises:

[0034] The first layer, the intermediate layer and the second layer are sequentially grown periodically, and the cycle number is 1-6.

[0035] The technical scheme provided by the embodiments of the present disclosure has the following beneficial effects:

[0036] Since the light-emitting diode provided by the embodiments of the present disclosure has a composite P-type layer, the composite P-type layer comprises a first layer, an intermediate layer and a second layer, and the first layer is an undoped N-type Al a Ga 1-a N layer, an undoped N-type In b Ga 1-b N layer or periodically stacked undoped Al c Ga 1-c N / In d Ga 1-d N layer, and the second layer is an undoped N-type Al e Ga 1-e N layer, an undoped N-type In f Ga 1-f N layer or periodically stacked undoped Al g Ga 1-g N / In h Ga 1-hN layer, so it can form an uneven interface with N polar surface, Mg is more likely to replace Ga, Al or In, reduce the formation energy of Mg, increase the solubility of Mg, and at the same time Ga, Al, In can reduce the activation energy of Mg, increase the activation rate of Mg, and help increase the effective doping of Mg, thereby increasing the hole concentration and the mobility of P-type layer holes, so that the P-type layer holes and N-type layer electrons can effectively recombine and emit light in the light-emitting area, thereby improving the luminous efficiency. In addition, the periodically stacked Al c Ga 1-c N / In d Ga 1-d N layer, Al g Ga 1-g N / In h Ga 1-h The N layer is more conducive to destroying the total reflection of light inside the LED and increasing diffuse reflection, thereby increasing the light extraction efficiency of the LED. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0038] Figure 1 is a structural schematic diagram of a light emitting diode provided by an embodiment of the present disclosure;

[0039] Figure 2 is a schematic structural diagram of another light emitting diode provided by an embodiment of the present disclosure;

[0040] Figure 3 is a flow chart of a method for preparing a light emitting diode provided by an embodiment of the present disclosure;

[0041] Figure 4 This is a flow chart of another method for preparing a light emitting diode provided in an embodiment of the present disclosure.

[0042] The symbols in the figure mean the following:

[0043] 10. Substrate;

[0044] 20. N-type layer;

[0045] 30. Multiple quantum well layer;

[0046] 40. Composite P-type layer;

[0047] 410, first layer; 420, middle layer; 430, second layer;

[0048] 50. Buffer layer;

[0049] 60. Undoped GaN layer;

[0050] 70. Electron blocking layer. DETAILED DESCRIPTION

[0051] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure will be further described in detail below with reference to the accompanying drawings.

[0052] Light-emitting diodes (LEDs) are a common type of light-emitting electronic device that is widely used in various fields.

[0053] In related technologies, GaN, a typical representative of III-V compound semiconductors, is a third-generation semiconductor material, following Si and GaAs. It possesses excellent properties such as a wide bandgap, a strong breakdown electric field, high electron mobility, and excellent thermal stability. The epitaxial layers of GaN-based light-emitting diodes primarily consist of an N-type layer, a multi-quantum well layer, and a P-type layer.

[0054] However, Mg is currently the most commonly used hole dopant. Since Mg is an acceptor element, its activation efficiency is very low, resulting in a large difference between the hole concentration obtained by P-type doping and the electron concentration obtained by N-type doping, resulting in a low hole mobility in the P-type layer and a low luminous efficiency of the light-emitting diode.

[0055] In order to solve the above technical problems, the present disclosure provides a light emitting diode having a composite P-type layer. Figure 1 is a schematic diagram of the structure of the light emitting diode, see Figure 1 In this embodiment, the light emitting diode includes: a substrate 10, and an N-type layer 20, a multi-quantum well layer 30 and a composite P-type layer 40 grown in sequence on one side of the substrate 10.

[0056] The composite P-type layer 40 includes a first layer 410, an intermediate layer 420, and a second layer 430 that are grown sequentially. The first layer 410 is a non-doped N-type Al a Ga 1-a N layer, undoped N-type In b Ga 1-b N layer or periodically stacked undoped Al c Ga 1-c N / In d Ga 1-d Any of the N layers, 0<a<1, 0<b<1, 0<c<1, 0<d<1, the second layer 430 is non-doped N-type Al e Ga 1-e N layer, undoped N-type In f Ga 1-fN layer or periodically stacked undoped Al g Ga 1-g N / In h Ga 1-h Any one of the N layers, 0<e<1, 0<f<1, 0<g<1, 0<h<1, the middle layer 420 is a Mg-doped GaN layer.

[0057] Since the light emitting diode provided by the embodiment of the present disclosure has a composite P-type layer 40, the composite P-type layer 40 includes a first layer 410, an intermediate layer 420 and a second layer 430, and the first layer 410 is a non-doped N-type Al a Ga 1-a N layer, undoped N-type In b Ga 1- b N layer or periodically stacked undoped Al c Ga 1-c N / In d Ga 1-d N layer, the second layer 430 is non-doped N-type Al e Ga 1-e N layer, undoped N-type In f Ga 1-f N layer or periodically stacked undoped Al g Ga 1-g N / In h Ga 1-h N layer, so it can form an uneven interface with N polar surface, Mg is more likely to replace Ga, Al or In, reduce the formation energy of Mg, increase the solubility of Mg, and at the same time Ga, Al, In can reduce the activation energy of Mg, increase the activation rate of Mg, and help increase the effective doping of Mg, thereby increasing the hole concentration and the mobility of the holes in the P-type layer, so that the holes in the P-type layer and the electrons in the N-type layer can effectively recombine and emit light in the light-emitting area, thereby improving the luminous efficiency. In addition, the periodically stacked Al c Ga 1-c N / In d Ga 1-d N layer, Al g Ga 1-g N / In h Ga 1-h The N layer is more conducive to destroying the total reflection of light inside the LED and increasing diffuse reflection, thereby increasing the light extraction efficiency of the LED.

[0058] In this embodiment, the types of the first layer 410 and the second layer 430 can be selected according to actual needs, and the two can be the same or different. For example, the first layer 410 is non-doped N-type Al a Ga1-a N layer, the second layer 430 is an undoped N-type Al e Ga 1-e N layer, or the first layer 410 is an undoped N-type Al a Ga 1-a N layer, and the second layer 430 is an undoped N-type In f Ga 1-f N layer. For more combinations, refer to Table 1, which is not limited by the present disclosure.

[0059]

[0060] Table 1

[0061] In other embodiments, the undoped N-type In b Ga 1-b N layer can be replaced by an undoped N-type In b N layer, the undoped N-type In f Ga 1-f N layer can be replaced by an undoped N-type In f N layer. After the replacement, the composite P-type layer 40 still has the same beneficial effects, which will not be described here.

[0062] Continuing to refer to Figure 1 , in the present embodiment, when the first layer 410 is an undoped N-type Al a Ga 1-a N layer or an undoped N-type In b Ga 1-b N layer, and when the second layer 430 is an undoped N-type Al e Ga 1-e N layer or an undoped N-type In f Ga 1- f The thickness of the first layer 410 and the second layer 430 is 1-10 nm.

[0063] In the above implementation, the first layer 410 and the second layer 430 are designed to have the above thickness, which can effectively ensure the effect of the first layer 410 and the second layer 430 on increasing the solubility of Mg and reducing the activation energy of Mg, and can also avoid the decrease of growth efficiency caused by too large thickness.

[0064] In the present embodiment, when the first layer 410 is an undoped Al c Ga 1-c N / In d Ga 1-d N layer, and when the second layer 430 is an undoped Al g Ga 1-g N / In hGa 1-h In the case of N layers, the thickness of the first layer 410 and the second layer 430 are both 1 to 3 nm.

[0065] In the above implementation, since the first layer 410 is non-doped Al c Ga 1-c N / In d Ga 1-d N layer, the second layer 430 is non-doped Al g Ga 1-g N / In h Ga 1-h The N layer, that is, the first layer 410 is a periodic stacked structure, and the second layer 430 is a periodic stacked structure. Therefore, appropriately reducing the thickness of the first layer 410 and the second layer 430 can also increase the solubility of Mg and reduce the activation energy of Mg.

[0066] In this embodiment, the thickness of the intermediate layer 420 is 95-730 nm.

[0067] In the above implementation, the intermediate layer 420 is designed to have the above thickness, which can ensure the thickness of the Mg-doped GaN layer and control the overall thickness of the composite P-type layer 40 to be 100-750 nm.

[0068] In this embodiment, the interface roughness between the first layer 410 and the second layer 430 is 15-24.

[0069] The interface roughness of the first layer 410 and the second layer 430 is designed to be the above value, which ensures that the first layer 410 and the second layer 430 can form an uneven interface with an N-polar surface, so that Mg can more easily replace Ga, Al or In, thereby reducing the formation energy of Mg and increasing the solubility of Mg.

[0070] In this embodiment, the N-type layer 20 is a heavily Si-doped N-type GaN layer with a thickness of 3-4 μm.

[0071] In this embodiment, the multi-quantum well layer 30 includes periodically grown InGaN well layers and GaN barrier layers, with the number of periods being 5 to 12. The thickness of the InGaN well layers is 2.5 to 4.5 nm, and the thickness of the GaN barrier layers is 8 to 12 nm.

[0072] In this embodiment, the light emitting diode further includes a buffer layer 50 . The buffer layer 50 is located on a side of the substrate 10 facing the N-type layer 20 .

[0073] By growing the buffer layer 50 on one side of the substrate 10 , the lattice mismatch problem can be effectively solved, and the stress in each thin film of the epitaxial layer can be relieved to a certain extent.

[0074] For example, the buffer layer 50 has a thickness of 20-30 nm.

[0075] In this embodiment, the light emitting diode further includes an undoped GaN layer 60 . The undoped GaN layer 60 is located on a side of the buffer layer 50 facing the N-type layer 20 .

[0076] Exemplarily, the thickness of the undoped GaN layer 60 is 2-3.5 um.

[0077] In this embodiment, the light emitting diode further includes an electron blocking layer 70 . The electron blocking layer 70 is located on a side of the multi-quantum well layer facing the N-type layer 20 .

[0078] Exemplarily, the electron blocking layer 70 is a P-type AlGaN layer, and the thickness of the electron blocking layer 70 is 100-450 nm.

[0079] Figure 2 Another light emitting diode with a composite P-type layer provided by the embodiment of the present disclosure is Figure 1 The difference of the light emitting diode shown mainly lies in the composite P-type layer 40 .

[0080] See also Figure 2 In this embodiment, the first layer 410 , the middle layer 420 and the second layer 430 are periodically stacked, and the number of periods is 1 to 6.

[0081] In this embodiment, the first layer 410 , the middle layer 420 and the second layer 430 are periodically stacked, which is more conducive to destroying the total reflection of light inside the LED and increasing diffuse reflection, thereby increasing the light extraction efficiency of the LED.

[0082] For example, when the first layer 410 , the middle layer 420 , and the second layer 430 are periodically stacked, the thickness of the first layer 410 and the second layer 430 are both 1 to 2 nm, and the thickness of the middle layer 420 is 15 to 120 nm.

[0083] When the first layer 410, the middle layer 420 and the second layer 430 are stacked periodically, the first layer 410 and the second layer 430 are designed to have the above thickness, which can not only effectively ensure that the first layer 410 and the second layer 430 increase the solubility of Mg and reduce the activation energy of Mg, but also avoid the reduction of growth efficiency due to excessive thickness.

[0084] In related technologies, traditional light-emitting diodes mainly include a substrate, and an N-type layer, a light-emitting layer, and a P-type layer sequentially formed on one side of the substrate. Using traditional light-emitting diodes as a control group, three sets of experiments were conducted, yielding the following results:

[0085] (1) The voltage (V) of the traditional light-emitting diode is 2.46, the brightness (MW) is 8.86, and the ESD yield is 96.6.

[0086] When the first layer 410 is non-doped N-type Al a Ga 1-a N layers, the middle layer 420 is a Mg-doped GaN layer, and the second layer 430 is a non-doped N-type Al e Ga 1-e For the N layer, the voltage (V) is 2.46, the brightness (MW) is 8.91, and the ESD yield is 96.8.

[0087] (2) The voltage (V) of the traditional light-emitting diode is 2.45, the brightness (MW) is 8.92, and the ESD yield is 97.0.

[0088] When the first layer 410 is non-doped N-type In b Ga 1-b N layer, the middle layer 420 is a Mg-doped GaN layer, and the second layer 430 is a non-doped N-type Al e Ga 1-e N layer, voltage (V) is 2.45, brightness (MW) is 8.99, and ESD yield is 97.3.

[0089] (3) The voltage (V) of the traditional light-emitting diode is 2.44, the brightness (MW) is 8.58, and the ESD yield is 97.4.

[0090] When the first layer 410 is non-doped N-type In b Ga 1-b N layer, the middle layer 420 is a Mg-doped GaN layer, and the second layer 430 is a non-doped N-type Al e Ga 1-e N layers, and the first layer 410, the middle layer 420 and the second layer 430 are a periodic stacked structure, the voltage (V) is 2.44, the brightness (MW) is 8.64, and the ESD yield is 97.6.

[0091] It can be seen that the light-emitting diode with a composite P-type layer provided by the embodiment of the present disclosure has a positive improvement in brightness and ESD yield compared to traditional light-emitting diodes, and the voltage is basically the same.

[0092] Figure 3 A flow chart of a method for preparing a light emitting diode having a composite P-type layer provided in an embodiment of the present disclosure, wherein the method is used to prepare Figure 1 The light-emitting diodes shown, combined with Figure 3 In this embodiment, the preparation method includes:

[0093] Step 301: Provide a substrate 10.

[0094] Step 302 : growing an N-type layer 20 on one side of the substrate 10 .

[0095] Step 303 : growing a multi-quantum well layer 30 on one side of the N-type layer 20 .

[0096] Step 304: growing a first layer 410 on one side of the multi-quantum well layer 30. The first layer 410 is a non-doped N-type Al a Ga 1-a N layer, undoped N-type In b Ga 1-b N layer or periodically stacked undoped Al c Ga 1-c N / In d Ga 1-d In any of the N layers, 0<a<1, 0<b<1, 0<c<1, 0<d<1.

[0097] Step 305 : growing an intermediate layer 420 on one side of the first layer 410 , wherein the intermediate layer 420 is a Mg-doped GaN layer.

[0098] Step 306: Grow a second layer 430 on one side of the middle layer 420. The second layer 430 is non-doped N-type Al. e Ga 1-e N layer, undoped N-type In f Ga 1-f N layer or periodically stacked undoped Al g Ga 1-g N / In h Ga 1-h In any of the N layers, 0<e<1, 0<f<1, 0<g<1, 0<h<1.

[0099] The composite P-type layer 40 is grown through steps 304 to 306 .

[0100] The light emitting diode prepared by the preparation method provided by the embodiment of the present disclosure includes a composite P-type layer 40, which includes a first layer 410, an intermediate layer 420 and a second layer 430, and the first layer 410 is a non-doped N-type Al a Ga 1-a N layer, undoped N-type In b Ga 1-b N layer or periodically stacked undoped Al c Ga 1-c N / In d Ga 1-d N layer, the second layer 430 is non-doped N-type Al e Ga 1-e N layer, undoped N-type In f Ga 1-f N layer or periodically stacked undoped Alg Ga 1-g N / In h Ga 1-h N layer, so it can form an uneven interface with N polar surface, Mg is more likely to replace Ga, Al or In, reduce the formation energy of Mg, increase the solubility of Mg, and at the same time Ga, Al, In can reduce the activation energy of Mg, increase the activation rate of Mg, and help increase the effective doping of Mg, thereby increasing the hole concentration and the mobility of the holes in the P-type layer, so that the holes in the P-type layer and the electrons in the N-type layer can effectively recombine and emit light in the light-emitting area, thereby improving the luminous efficiency. In addition, the periodically stacked Al c Ga 1- c N / In d Ga 1-d N layer, Al g Ga 1-g N / In h Ga 1-h The N layer is more conducive to destroying the total reflection of light inside the LED and increasing diffuse reflection, thereby increasing the light extraction efficiency of the LED.

[0101] Figure 4 A flow chart of another method for preparing a light emitting diode having a composite P-type layer provided in an embodiment of the present disclosure, wherein the method is used to prepare Figure 1 and Figure 2 The light-emitting diodes shown, combined with Figure 4 In this embodiment, the preparation method includes:

[0102] Step 401: Provide a substrate 10.

[0103] Exemplarily, the substrate 10 is heated to 1000-1200° C. for surface cleaning treatment for 5-10 minutes.

[0104] Step 402 : growing a buffer layer 50 on one side of the substrate 10 .

[0105] In step 402, the growth temperature is set to 750-900°C, the growth pressure is set to 100-300 Torr, and the growth thickness is set to 20-30 nm.

[0106] By growing the buffer layer 50 on one side of the substrate 10 , the lattice mismatch problem can be effectively solved, and the stress in each thin film of the epitaxial layer can be relieved to a certain extent.

[0107] Step 403 : growing a non-doped GaN layer 60 on one side of the buffer layer 50 .

[0108] In step 403 , the growth pressure is set to 100 to 500 torr, and the growth thickness is set to 2 to 3.5 um.

[0109] Step 404 : growing an N-type layer 20 on one side of the undoped GaN layer 60 .

[0110] In step 404 , the N-type layer 20 is a heavily Si-doped n-type GaN layer, and the growth temperature is set to 1000-1200° C., the growth pressure is set to 100-500 Torr, and the growth thickness is set to 3-4 μm.

[0111] Step 405 : growing a multi-quantum well layer 30 on one side of the N-type layer 20 .

[0112] In step 405, InGaN well layers and GaN barrier layers are periodically grown, with the number of periods ranging from 5 to 12. The growth temperature of the InGaN well layers and the GaN barrier layers is set to 720° C. to 950° C., the growth pressure is set to 100 to 500 torr, the thickness of the InGaN well layers is set to 2.5 to 4.5 nm, and the thickness of the GaN barrier layers is set to 8 to 12 nm.

[0113] Step 406 : growing an electron blocking layer 70 on one side of the multi-quantum well layer 30 .

[0114] In step 406 , the electron blocking layer 70 is a P-type AlGaN layer, and the growth temperature is set to 700-800° C., the growth pressure is set to 100-500 Torr, and the growth thickness is set to 100-450 nm.

[0115] Step 407 : growing a first layer 410 on one side of the electron blocking layer 70 .

[0116] In step 407, the first layer 410 is non-doped N-type Al a Ga 1-a N layer, undoped N-type In b Ga 1-b N layer or periodically stacked undoped Al c Ga 1-c N / In d Ga 1-d In any of the N layers, 0<a<1, 0<b<1, 0<c<1, 0<d<1.

[0117] For example, when the first layer 410 is non-doped N-type Al a Ga 1-a N layer or undoped N-type In b Ga 1-bIn the case of the N layer, the interface roughness of the first layer 410 is 15-24, the growth temperature is 800-980° C., the growth time is 15-300 s, and the growth thickness is 1-10 nm.

[0118] For example, when the first layer 410 is non-doped Al c Ga 1-c N / In d Ga 1-d N layer, the interface roughness of the first layer 410 is 15-24, the growth temperature is 800-980° C., the growth time does not exceed 120 s, the growth thickness is 1-3 nm, and the number of cycles is 1-3.

[0119] Step 408 : growing an intermediate layer 420 on one side of the first layer 410 .

[0120] In step 408 , the middle layer 420 is a Mg-doped GaN layer, with a growth temperature of 800-980° C., a growth time of 5-600 s, a growth thickness of 95-730 nm, and a growth pressure of 100-500 Torr.

[0121] Step 409 : growing a second layer 430 on one side of the intermediate layer 420 .

[0122] In step 409, the second layer 430 is non-doped N-type Al e Ga 1-e N layer, undoped N-type In f Ga 1-f N layer or periodically stacked undoped Al g Ga 1-g N / In h Ga 1-h In any of the N layers, 0<e<1, 0<f<1, 0<g<1, 0<h<1.

[0123] For example, when the second layer 430 is non-doped N-type Al e Ga 1-e N layer or undoped N-type In f Ga 1-f In the case of the N layer, the interface roughness of the second layer 430 is 15-24, the growth temperature is 800-980° C., the growth time is 15-300 s, and the growth thickness is 1-10 nm.

[0124] For example, when the second layer 430 is non-doped Al g Ga 1-g N / In h Ga 1-hThe interface roughness of the N layer and the second layer 430 is 15-24, the growth temperature is 800-980° C., the growth time is no more than 120 s, the growth thickness is 1-3 nm, and the number of cycles is 1-3.

[0125] In some examples, the composite P-type layer 40 includes only the first layer 410, the middle layer 420, and the second layer 430 (see Figure 1 In this case, step 410 is not performed. In other examples, the composite P-type layer 40 includes a first layer 410, an intermediate layer 420, and a second layer 430 that are periodically stacked (see Figure 2 ). In this case, step 410 is executed.

[0126] Step 410: Periodically grow a first layer 410, an intermediate layer 420, and a second layer 430 in sequence, with the number of cycles being 1 to 6.

[0127] In step 410 , the growth method of the first layer 410 is the same as that of step 407 , the growth method of the intermediate layer 420 is the same as that of step 408 , and the growth method of the second layer 430 is the same as that of step 409 , which will not be repeated here.

[0128] The light emitting diode prepared by the preparation method provided by the embodiment of the present disclosure includes a composite P-type layer 40, which includes a first layer 410, an intermediate layer 420 and a second layer 430, and the first layer 410 is a non-doped N-type Al a Ga 1-a N layer, undoped N-type In b Ga 1-b N layer or periodically stacked undoped Al c Ga 1-c N / In d Ga 1-d N layer, the second layer 430 is non-doped N-type Al e Ga 1-e N layer, undoped N-type In f Ga 1-f N layer or periodically stacked undoped Al g Ga 1-g N / In h Ga 1-h N layer, so it can form an uneven interface with N polar surface, Mg is more likely to replace Ga, Al or In, reduce the formation energy of Mg, increase the solubility of Mg, and at the same time Ga, Al, In can reduce the activation energy of Mg, increase the activation rate of Mg, and help increase the effective doping of Mg, thereby increasing the hole concentration and the mobility of holes in the P-type layer, so that the holes in the P-type layer and the electrons in the N-type layer can effectively recombine and emit light in the light-emitting area, thereby improving the luminous efficiency. In addition, Al c Ga1-c N / In d Ga 1-d N layer, Al g Ga 1-g N / In h Ga 1-h The N layer is more conducive to destroying the total reflection of light inside the LED and increasing diffuse reflection, thereby increasing the light extraction efficiency of the LED.

[0129] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by persons of ordinary skill in the field to which the present disclosure belongs. The words “first”, “second”, “third” and similar terms used in the patent application specification and claims of the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as “a” or “an” do not indicate a quantity limitation, but rather indicate the presence of at least one. Words such as “include” or “comprise” mean that the elements or objects appearing before “include” or “comprises” include the elements or objects listed after “include” or “comprises” and their equivalents, and do not exclude other elements or objects. Words such as “connect” or “connected” are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. “Up”, “down”, “left”, “right” and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0130] The above description is merely an optional embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the scope of protection of the present disclosure.

Claims

1. A light emitting diode having a composite P-type layer, characterized in that: include: A substrate (10), and an N-type layer (20), a multi-quantum well layer (30), and a composite P-type layer (40) grown in sequence on one side of the substrate (10); The composite P-type layer (40) comprises a first layer (410), an intermediate layer (420), and a second layer (430) grown in sequence; The first layer (410) is non-doped N-type Al a Ga 1-a N layer, undoped N-type In b Ga 1-b N layer or periodically stacked undoped Al c Ga 1-c N / In d Ga 1-d Any of the N layers, 0<a<1, 0<b<1, 0<c<1, 0<d<1; The second layer (430) is non-doped N-type Al e Ga 1-e N layer, undoped N-type In f Ga 1-f N layer or periodically stacked undoped Al g Ga 1-g N / In h Ga 1-h Any of the N layers, 0<e<1, 0<f<1, 0<g<1, 0<h<1; The intermediate layer (420) is a Mg-doped GaN layer.

2. The light emitting diode according to claim 1, characterized in that When the first layer (410) is non-doped N-type Al a Ga 1-a N layer or undoped N-type In b Ga 1-b N layer, and when the second layer (430) is non-doped N-type Al e Ga 1-e N layer or undoped N-type In f Ga 1-f When there are N layers, the thickness of the first layer (410) and the second layer (430) are both 1 to 10 nm; When the first layer (410) is non-doped Al c Ga 1-c N / In d Ga 1-d N layer, and when the second layer (430) is non-doped Al g Ga 1-g N / In h Ga 1-h When there are N layers, the thickness of the first layer (410) and the second layer (430) are both 1 to 3 nm; The thickness of the intermediate layer (420) is 95-730 nm.

3. The light emitting diode according to claim 1, characterized in that The first layer (410), the middle layer (420) and the second layer (430) are stacked periodically, with the number of periods being 1 to 6.

4. The light emitting diode according to claim 3, characterized in that The thickness of the first layer (410) and the second layer (430) are both 1 to 2 nm; The thickness of the intermediate layer (420) is 15-120 nm.

5. A method for preparing a light-emitting diode having a composite P-type layer, characterized in that: include: Providing a substrate (10); An N-type layer (20), a multi-quantum well layer (30), and a composite P-type layer (40) are sequentially grown on one side of the substrate (10); The composite P-type layer (40) is grown in the following manner: A first layer (410), an intermediate layer (420) and a second layer (430) are grown in sequence, wherein: The first layer (410) is non-doped N-type Al a Ga 1-a N layer, undoped N-type In b Ga 1-b N layer or periodically stacked undoped Al c Ga 1-c N / In d Ga 1-d Any of the N layers, 0<a<1, 0<b<1, 0<c<1, 0<d<1; The second layer (430) is non-doped N-type Al e Ga 1-e N layer, undoped N-type In f Ga 1-f N layer or periodically stacked undoped Al g Ga 1-g N / In h Ga 1-h Any of the N layers, 0<e<1, 0<f<1, 0<g<1, 0<h<1; The intermediate layer (420) is a Mg-doped GaN layer.

6. The preparation method according to claim 5, characterized in that Growing the first layer (410) and the second layer (430) includes: When the first layer (410) is non-doped N-type Al a Ga 1-a N layer or undoped N-type In b Ga 1-b N layer, and when the second layer (430) is non-doped N-type Al e Ga 1-e N layer or undoped N-type In f Ga 1-f In the case of N layers, the growth temperature of the first layer (410) and the second layer (430) is 800-980°C, the growth time is 15-300s, and the growth thickness is 1-10nm.

7. The preparation method according to claim 5, characterized in that Growing the first layer (410) and the second layer (430) includes: When the first layer (410) is non-doped Al c Ga 1-c N / In d Ga 1-d N layer, and when the second layer (430) is non-doped Al g Ga 1-g N / In h Ga 1-h When there are N layers, the growth temperature of the first layer (410) and the second layer (430) is 800-980°C, the growth time does not exceed 120s, the growth thickness is 1-3nm, and the number of cycles is 1-3.

8. The preparation method according to claim 5, characterized in that Growing the intermediate layer (420) includes: The growth temperature is 800-980° C., the growth time is 5-600 s, the growth thickness is 95-730 nm, and the growth pressure is 100-500 Torr.

9. The preparation method according to claim 5, characterized in that Also includes: The first layer (410), the middle layer (420) and the second layer (430) are grown periodically in sequence, with the number of cycles being 1 to 6.

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