CN115377259B - Light-emitting diode epitaxial wafer and preparation method thereof, light-emitting diode - Google Patents

Abstract

The invention discloses a light-emitting diode epitaxial wafer, a preparation method thereof and a light-emitting diode, and relates to the field of semiconductor optoelectronic devices. The light-emitting diode epitaxial wafer includes a substrate and a buffer layer, a U-GaN layer, an N-GaN layer, an active layer, an electron blocking layer and a P-GaN layer sequentially arranged on the substrate, and the active layer includes a plurality of alternately stacked A quantum well layer and a quantum barrier layer; the quantum well layer includes a first quantum well sublayer, a second quantum well sublayer and a third quantum well sublayer stacked in sequence; wherein, the first quantum well sublayer is N -InGaN layer, the second quantum well sublayer is a periodic structure formed by multiple alternately stacked InAlGaN layers and InN layers, and the third quantum well sublayer is a P-InGaN layer. By implementing the invention, the light efficiency of the light emitting diode can be improved.

Description

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

technical field

The invention relates to the field of semiconductor optoelectronic devices, in particular to a light-emitting diode epitaxial wafer, a preparation method thereof, and a light-emitting diode.

Background technique

In common GaN-based light-emitting diodes, InGaN (quantum well layer)/GaN (quantum barrier layer) is generally used as the active layer, but due to the serious lattice mismatch between the quantum well layer and the quantum barrier layer, and the quantum well The layer needs to be doped with higher In components, usually the growth temperature is lower, and the defects increase, so there is serious piezoelectric polarization in the multi-quantum well, and there is also a great stress in the quantum well layer, which leads to the multi-quantum well energy band The inclination of electrons and holes will cause serious spatial separation when passing through the quantum well region, resulting in quantum confinement Stark effect (QCSE), which reduces the luminous efficiency of light-emitting diodes. On the other hand, in conventional light-emitting diodes, due to the difficulty in the activation of Mg, the hole concentration is low, so there is usually a phenomenon of insufficient holes in the active layer, which also reduces the luminous efficiency of the light-emitting diode.

Contents of the invention

The technical problem to be solved by the present invention is to provide a high-efficiency light-emitting diode epitaxial wafer and a preparation method thereof, which can improve the light-efficiency of the light-emitting diode.

The technical problem to be solved by the present invention is to provide a light emitting diode with high light efficiency.

In order to solve the above problems, the present invention discloses a light-emitting diode epitaxial wafer, which includes a substrate, a buffer layer, a U-GaN layer, an N-GaN layer, an active layer, an electron blocking layer and P-GaN layer, the active layer includes a plurality of alternately stacked quantum well layers and quantum barrier layers; the quantum well layer includes sequentially stacked first quantum well sublayers, second quantum well sublayers and third quantum well layers Well sublayer;

Wherein, the first quantum well sublayer is an N-InGaN layer, the second quantum well sublayer is a periodic structure formed by a plurality of alternately stacked InAlGaN layers and InN layers, and the third quantum well sublayer is P-InGaN layer.

As an improvement of the above technical solution, the proportion of the In component in the first quantum well sublayer is 0.05-0.1, the doping element of the first quantum well sublayer is Si, and the doping concentration is 5×10 ¹⁵ -1×10 ¹⁶ cm ^-3 .

As an improvement of the above technical solution, the proportion of the In component in the InAlGaN layer is 0.1-0.2, the proportion of the Al component is 0.02-0.5, and the proportion of the In component in the InN layer is 0.2-0.5.

As an improvement of the above technical solution, the proportion of the In component in the third quantum well sublayer is 0.05-0.1, the doping element of the third quantum well sublayer is Mg, and the doping concentration is 5×10 ¹⁵ -1×10 ¹⁷ cm ^-3 .

As an improvement of the above technical solution, the thickness of the first quantum well sublayer is 0.3-4nm, and the thickness of the third quantum well sublayer is 0.3-4nm;

The number of periods of the second quantum well sublayer is 2-6, wherein the thickness of a single InAlGaN layer is 0.1-1 nm, and the thickness of a single InN layer is 0.1-1 nm.

As an improvement of the above technical solution, the first quantum well sublayer is a pulse-doped N-InGaN layer, which is formed by a plurality of alternately stacked doped N-InGaN layers and non-doped N-InGaN layers Periodic structure, the number of periods is 2-6;

Wherein, the thickness of a single doped N-InGaN layer is 0.1-0.3 nm, and the thickness of a single non-doped N-InGaN layer is 0.1-0.3 nm;

The ratio of the In component in the InN layer is 0.3-0.5.

As an improvement of the above technical solution, the third quantum well sublayer is a pulse-doped P-InGaN layer, which is formed by a plurality of alternately stacked doped P-InGaN layers and non-doped P-InGaN layers Periodic structure, the number of periods is 2-6;

The thickness of a single doped P-InGaN layer is 0.1-0.3nm, and the thickness of a single non-doped P-InGaN layer is 0.1-0.3nm.

Correspondingly, the present invention also discloses a method for preparing a light-emitting diode epitaxial wafer, which is used to prepare the above-mentioned light-emitting diode epitaxial wafer, which includes:

Provide a substrate on which a buffer layer, a U-GaN layer, an N-GaN layer, an active layer, an electron blocking layer, and a P-GaN layer are sequentially grown; the active layer includes a plurality of alternately stacked quantum a well layer and a quantum barrier layer, the quantum well layer includes a first quantum well sublayer, a second quantum well sublayer and a third quantum well sublayer stacked in sequence;

Wherein, the first quantum well sublayer is an N-InGaN layer, the second quantum well sublayer is a periodic structure formed by a plurality of alternately stacked InAlGaN layers and InN layers, and the third quantum well sublayer is P-InGaN layer;

The growth temperature of the first quantum well sublayer, the second quantum well sublayer and the third quantum well sublayer are all 700-800° C., and the growth pressure is 100-500 torr.

As an improvement of the above technical solution, the carrier gas used in the growth of the first quantum well sublayer, the second quantum well sublayer and the third quantum well sublayer is nitrogen or argon.

Correspondingly, the present invention also discloses a light-emitting diode, which includes the above-mentioned light-emitting diode epitaxial wafer.

Implement the present invention, have following beneficial effect:

1. In the light-emitting diode epitaxial wafer of the present invention, the quantum well layer of the active layer includes the first quantum well sublayer, the second quantum well sublayer and the third quantum well sublayer stacked in sequence, wherein the first quantum well sublayer The N-InGaN layer is N-InGaN layer, which can reduce the polarization electric field effect of the quantum well, increase the overlapping of electron and hole wave functions, and increase the internal quantum efficiency; and the N-type doping can weaken the quantum well layer. electric field. The third quantum well sublayer is a P-InGaN layer, which increases the holes in the quantum well and improves the probability of electron-hole recombination, and the two can cooperate with the first quantum well sublayer to reduce the polarization electric field The role of promoting the recombination of electrons and holes, improving the luminous efficiency. Among them, the second quantum well sublayer is a periodic structure formed by alternately stacking InAlGaN layers and InN layers. Specifically, Al is introduced into InAlGaN, which has high lattice integrity, and then wraps less stable InN in stable InAlGaN In this way, the content of the In component in the quantum well layer is effectively increased, the lattice quality of the quantum well layer is improved, and the luminous efficiency is further improved. In addition, the Al introduced in InAlGaN can offset the stress brought by In, weaken the polarization electric field, and improve the luminous efficiency.

2. In the light-emitting diode epitaxial wafer of the present invention, the N-InGaN layer of the first quantum well sublayer adopts a pulse-doped N-InGaN layer. Based on this structure, the lattice quality of the quantum well layer can be further improved, and the In composition can be improved. content, and reduce the probability of non-radiative recombination.

3. In the light-emitting diode epitaxial wafer of the present invention, the P-InGaN layer of the third quantum well sublayer adopts a pulse doping method, which can improve the uniformity of hole distribution, effectively improve the expansion performance of holes, and further improve the electron hole The recombination probability of holes improves the luminous efficiency.

Description of drawings

Fig. 1 is a schematic structural view of a light-emitting diode epitaxial wafer in an embodiment of the present invention;

Fig. 2 is a schematic structural diagram of a quantum well layer in an embodiment of the present invention;

Fig. 3 is a schematic structural view of the first quantum well sublayer in an embodiment of the present invention;

4 is a schematic structural view of a third quantum well sublayer in an embodiment of the present invention;

Fig. 5 is a flow chart of a method for preparing a light-emitting diode epitaxial wafer in an embodiment of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below.

Referring to Fig. 1 and Fig. 2, the present invention discloses a high-efficiency light-emitting diode epitaxial wafer, comprising a substrate 1 and a buffer layer 2, a U-GaN layer 3, an N-GaN layer 4, and an organic Source layer 5 , electron blocking layer 6 and P-GaN layer 7 . Wherein, the active layer 5 includes a plurality of alternately stacked quantum well layers 51 and quantum barrier layers 52, and the number of stacking periods is 3-15.

Wherein, the quantum well layer 51 includes a first quantum well sublayer 511 , a second quantum well sublayer 512 and a third quantum well sublayer 513 stacked in sequence. Specifically, the first quantum well sublayer 511 is an N-InGaN layer, the second quantum well sublayer 512 is a periodic structure formed by a plurality of alternately stacked InAlGaN layers 512a and InN layers 512b, and the third quantum well sublayer 513 is P-InGaN layer. Based on the above structure, one weakens the effect of the polarized electric field in the quantum well layer, and increases the recombination probability of electrons and holes in the quantum well layer; the two effectively increase the content of the In component in the quantum well layer, improving The lattice quality of the quantum well layer is improved; the combination of the two effectively improves the luminous efficiency.

Wherein, the first quantum well sublayer 511 can provide electrons, improve the overlap of electron and hole wave functions, and increase internal quantum efficiency. The doping element of the first quantum well sublayer 511 is Si, but not limited thereto. Si is preferred, the atomic radius of Si is small, and the doping of Si can improve the lattice quality of the quantum well layer 51 . The concentration of N-type doping in the first quantum well sublayer 511 is 5×10 ¹⁵ -1×10 ¹⁶ cm ^-3 , and when the doping concentration is less than 5×10 ¹⁵ cm ^-3 , it is difficult to effectively weaken the Polarization electric field; when the doping concentration>1×10 ¹⁶ cm ^-3 , it is easy to form non-radiative recombination center and reduce the luminous efficiency. Exemplarily, the doping concentration of Si in the first quantum well sublayer 511 is 6×10 ¹⁶ cm ^-3 , 7×10 ¹⁶ cm ^-3 , 8×10 ¹⁶ cm ^-3 , 9×10 ¹⁶ cm ^-3 or 9.5×10 ¹⁶ cm ^-3 , but not limited thereto.

The proportion of In component in the first quantum well sub-layer 511 is 0.05-0.1, and the low proportion of In component can play a good transition role and weaken the polarization effect of the quantum well layer 51 . Exemplarily, the proportion of the In component in the first quantum well sub-layer 511 is 0.06, 0.065, 0.07, 0.07, 0.08 or 0.09, but not limited thereto.

The thickness of the first quantum well sublayer 511 is 0.3-4nm, when its thickness＜0.3nm, it is difficult to effectively weaken the polarization electric field of the quantum well layer 51; when the thickness＞4nm, it will make electrons migrate in the quantum well layer 51 If the speed is too fast, the recombination of electrons and holes in the quantum well layer 51 will be reduced, and the luminous efficiency will be reduced. Exemplarily, the thickness of the first quantum well sublayer 511 is 0.8 nm, 1.3 nm, 1.8 nm, 2.3 nm, 2.8 nm, 3.3 nm or 3.8 nm, but not limited thereto.

Preferably, referring to FIG. 3, in one embodiment of the present invention, the first quantum well sublayer 511 is a pulse-doped N-InGaN layer, that is, it is a plurality of alternately stacked doped N-InGaN layers 511a A periodic structure formed with the non-doped N-InGaN layer 511b. Based on this structural arrangement, the content of the In component in the InN layer 512b can be increased, the probability of non-radiative recombination can be reduced, and the luminous efficiency can be improved.

Specifically, the thickness of the single doped N-InGaN layer 511a is 0.1-0.3 nm, exemplarily 0.13 nm, 0.16 nm, 0.19 nm, 0.22 nm, 0.25 nm or 0.28 nm, but not limited thereto. The thickness of the single undoped N-InGaN layer 511b is 0.1-0.3 nm, exemplarily 0.13 nm, 0.16 nm, 0.19 nm, 0.22 nm, 0.25 nm or 0.28 nm, but not limited thereto. The period number of the first quantum well sublayer 511 is 2-6.

Wherein, the third quantum well sublayer 513 can provide holes, thereby increasing the probability of electron-hole recombination. In addition, the third quantum well sublayer 513 can cooperate with the first quantum well sublayer 511 to reduce the effect of the polarization electric field and improve the recombination of electrons and holes. The combination of the two effectively improves the luminous efficiency. The doping element of the third quantum well sublayer 513 is Mg, but not limited thereto. The P-type doping concentration in the third quantum well sublayer 513 is 5×10 ¹⁵ -1×10 ¹⁷ cm ^-3 , and when the doping concentration is less than 5×10 ¹⁵ cm ^-3 , it is difficult to effectively weaken the Polarization electric field; when the doping concentration > 1×10 ¹⁷ cm ^-3 , it is easy to form non-radiative recombination centers and reduce the luminous efficiency. Exemplarily, the doping concentration of Mg in the third quantum well sublayer 513 is 8×10 ¹⁶ cm ^-3 , 2.5×10 ¹⁷ cm ^-3 , 4×10 ¹⁷ cm ^-3 , 6×10 ¹⁷ cm ^-3 or 8×10 ¹⁷ cm ^-3 , but not limited thereto.

The proportion of In component in the third quantum well sublayer 513 is 0.05-0.1, and the third quantum well sublayer 513 is set close to the quantum barrier layer 52 (GaN), so as to maintain its low In content and reduce the lattice mismatch , improve luminous efficiency. Exemplarily, the proportion of the In component in the third quantum well sub-layer 513 is 0.064, 0.068, 0.076, 0.083 or 0.095, but not limited thereto.

The thickness of the third quantum well sublayer 513 is 0.3-4nm, when its thickness＜0.3nm, it is difficult to effectively weaken the polarization electric field of the quantum well layer 51; when the thickness＞4nm, it will reduce the holes in the quantum well layer 51 The migration speed decreases, the recombination of holes and electrons in the quantum well layer 51 is reduced, and the luminous efficiency is reduced. Exemplarily, the thickness of the first quantum well sublayer 511 is 0.8 nm, 1.3 nm, 1.8 nm, 2.3 nm, 2.8 nm, 3.3 nm or 3.8 nm, but not limited thereto.

Preferably, referring to FIG. 4, in one embodiment of the present invention, the third quantum well sublayer 513 is a pulse-doped P-InGaN layer, that is, it is a plurality of alternately stacked doped P-InGaN layers 513a A periodic structure formed with the undoped P-InGaN layer 513b. Based on this structural setting, the uniformity of hole distribution can be improved, the expansion performance of holes can be effectively improved, the recombination probability of electron holes can be further improved, and the luminous efficiency can be improved. Specifically, the thickness of the single doped P-InGaN layer 513a is 0.1-0.3nm, exemplarily 0.14nm, 0.18nm, 0.22nm or 0.26nm, but not limited thereto. The thickness of a single undoped P-InGaN layer 513b is 0.1-0.3 nm, exemplarily 0.12 nm, 0.16 nm, 0.18 nm, 0.22 nm, 0.24 nm or 0.28 nm, but not limited thereto. The number of periods of the third quantum well sublayer 513 is 2-6.

Wherein, the second quantum well sublayer 512 is a periodic structure formed by a plurality of alternately stacked InAlGaN layers 512a and InN layers 512b. Among them, Al is introduced into the InAlGaN layer 512a. Since the atomic radius of the Al atom is small, and the strength of the covalent bond between the Al atom and the N atom is much greater than the strength of the covalent bond between the Ga atom and the N atom, the GaN The integrity of the lattice, so the InALGaN material is better and more stable than the InGaN lattice. Furthermore, through the combination of InAlGaN-InN-InAlGaN formed by the second quantum well sub-layer 512, the relatively unstable InN layer 512b with high In composition can be wrapped in the middle to avoid the increase of defects caused by the high In composition. The problem of poor lattice quality can be solved, so as to obtain a quantum well layer with high In composition, stable structure, good luminous efficiency and high luminous efficiency. Further, the tensile stress generated by Al introduced into the InAlGaN layer 512a and the compressive stress introduced by In atoms can be partially offset, effectively reducing the stress in the multi-quantum wells, reducing the polarization electric field, and thus improving the luminous efficiency.

Specifically, the proportion of the Al component in the InAlGaN layer 512a is 0.02-0.1. When the proportion of the Al component is less than 0.02, the crystal quality of the InAlGaN layer 512a is relatively poor, and the effect of improving the overall In composition of the quantum well layer 51 is relatively small. Poor; when the ratio of the Al composition is greater than 0.1, the potential barrier of the quantum well layer 51 is relatively high, and the effect of the InAlGaN layer 512a on improving the luminous efficiency is weakened. Exemplarily, the proportion of the Al component in the InAlGaN layer 512a is 0.03, 0.04, 0.05, 0.06, 0.07 or 0.08, but not limited thereto. The proportion of the In component in the InAlGaN layer 512a is 0.1-0.2. When the proportion of the In component is less than 0.1, the lattice mismatch between the InAlGaN layer 512a and the InN layer 512b is large, which is not conducive to improving the luminous efficiency; when the In component When the proportion of >0.1, the crystal quality of the InAlGaN layer 512a is relatively poor, and the effect of increasing the In composition of the quantum well layer 51 as a whole is poor. Exemplarily, the proportion of the In component in the InAlGaN layer 512a is 0.12, 0.14, 0.16 or 0.18, but not limited thereto.

Specifically, the proportion of the In component in the InN layer 512b is 0.2-0.5, exemplarily 0.22, 0.25, 0.28, 0.32, 0.35 or 0.38, but not limited thereto. Preferably, in one embodiment of the present invention, when a pulse-doped N-InGaN layer is used as the first quantum well sublayer 511 , the proportion of the In component in the InN layer 512b is 0.35-0.5.

Specifically, the number of periods of the second quantum well sublayer 512 is 2-6, and the thickness of a single InAlGaN layer 512a is 0.1-1nm, exemplarily 0.2nm, 0.3nm, 0.5nm, 0.7nm or 0.8nm, but Not limited to this. The thickness of a single InN layer 512b is 0.1-1 nm, exemplarily 0.15 nm, 0.3 nm, 0.45 nm, 0.6 nm or 0.8 nm, but not limited thereto.

Wherein, the quantum barrier layer 52 is a GaN layer, but not limited thereto. The thickness of the quantum barrier layer 52 is 3-15 nm, exemplarily 4 nm, 6 nm, 7 nm, 8 nm, 10 nm, 12 nm or 14 nm, but not limited thereto.

Wherein, the substrate 1 may be a sapphire substrate, a silicon substrate, or a silicon carbide substrate, but is not limited thereto.

Wherein, the buffer layer 2 may be an AlN layer and/or an AlGaN layer, but not limited thereto; preferably, the buffer layer 2 is an AlGaN layer. The buffer layer 2 has a thickness of 20-100 nm, exemplarily 25 nm, 35 nm, 45 nm, 55 nm, 65 nm, 75 nm or 90 nm, but not limited thereto.

Wherein, the thickness of the U-GaN layer 3 is 300-800nm, exemplarily 360nm, 420nm, 480nm, 540nm, 600nm, 660nm or 720nm, but not limited thereto.

Wherein, the doping element of the N-GaN layer 4 is Si, but not limited thereto. The doping concentration of the N-GaN layer 4 is 5×10 ¹⁹ -5×10 ¹⁹ cm ⁻³ , and the thickness is 1-3 μm.

Wherein, the electron blocking layer 6 is an AlGaN layer or an AlInGaN layer, but not limited thereto. Preferably, in one embodiment of the present invention, the electron blocking layer 6 is a periodic structure in which Al _a Ga _1-a N layers and In _b Ga _1-b N layers are alternately grown; wherein, a is 0.05-0.2, b is 0.1-0.5. The thickness of the electron blocking layer 6 is 50-150 nm.

Wherein, the doping element in the P-GaN layer 7 is Mg, but not limited thereto. The doping concentration of Mg in the P-GaN layer 7 is 5×10 ¹⁷ -1×10 ²⁰ cm ⁻³ . The thickness of the P-GaN layer 7 is 200-300 nm.

Correspondingly, referring to FIG. 5 , the present application also discloses a method for preparing a light-emitting diode epitaxial wafer, which is used to prepare the above-mentioned light-emitting diode epitaxial wafer, which includes the following steps:

S100: providing a substrate;

Specifically, the substrate is a sapphire substrate, a silicon substrate, or a silicon carbide substrate, but is not limited thereto. Preferred is a sapphire substrate.

Preferably, in one embodiment of the present invention, the substrate is loaded into MOCVD, and annealed at 1000-1200°C, 200-600torr, and hydrogen atmosphere for 5-8min to remove particles, oxides, etc. on the substrate surface Impurities.

S200: sequentially growing a buffer layer, a U-GaN layer, an N-GaN layer, an active layer, an electron blocking layer, and a P-GaN layer on the substrate;

Specifically, S200 includes:

S210: growing a buffer layer on the substrate;

Specifically, an AlGaN layer may be grown by MOCVD as a buffer layer, or an AlN layer may be grown by PVD as a buffer layer, but not limited thereto. Preferably, the AlGaN layer is grown by MOCVD, the growth temperature is 500-700° C., and the growth pressure is 200-400 torr. During growth, NH ₃ is fed into the MOCVD reaction chamber as the N source; H ₂ and N ₂ are used as the carrier gas, TMAl is fed as the Al source, and TMGa is fed as the Ga source.

S220: growing a U-GaN layer on the buffer layer;

Specifically, the U-GaN layer is grown in MOCVD at a growth temperature of 1100-1150° C. and a growth pressure of 100-500 torr. During growth, NH ₃ is fed into the MOCVD reaction chamber as the N source; H ₂ and N ₂ are used as the carrier gas, and TMGa is fed as the Ga source.

S230: growing an N-GaN layer on the U-GaN layer;

Specifically, the N-GaN layer is grown in MOCVD at a growth temperature of 1100-1150° C. and a growth pressure of 100-500 torr. During growth, NH ₃ is introduced into the MOCVD reaction chamber as the N source, SiH ₄ is introduced as the N-type dopant source; H ₂ and N ₂ are used as the carrier gas, and TMGa is introduced as the Ga source.

S240: growing an active layer on the N-GaN layer;

Specifically, quantum well layers and quantum barrier layers are grown periodically in MOCVD to form an active layer. Among them, the growth temperature of the quantum barrier layer is 800-900°C, and the growth pressure is 100-500torr. During the growth, NH ₃ is introduced into the MOCVD reaction chamber as the N source, H ₂ and N ₂ are used as the carrier gas, and TEGa as Ga source.

Specifically, in one embodiment of the present invention, growing the quantum well layer includes the following steps:

S1: growing the first quantum well sublayer on the N-GaN layer;

Specifically, an N-InGaN layer is grown in MOCVD as the first quantum well sublayer. The growth temperature of the first quantum well sublayer is 700-800° C., and the growth pressure is 100-500 torr. During growth, NH ₃ is introduced into the MOCVD reaction chamber as the N source, and SiH ₄ is introduced as the N-type dopant source; Ar or N ₂ is used as the carrier gas, TMAl is introduced as the Al source, and TMIn is introduced as the In source. TEGa was introduced as a Ga source.

Preferably, in one embodiment of the present invention, the first quantum well sublayer is grown by pulse doping, that is, _SiH is controlled to be fed in pulse form to periodically form doped N-InGaN layers and non-doped N-InGaN layers. heterogeneous N-InGaN layer.

S2: growing a second quantum well sublayer on the first quantum well sublayer;

Specifically, an InAlGaN layer and an InN layer are grown periodically in MOCVD as the second quantum well sublayer. The growth temperature of the second quantum well sublayer is 700-800° C., and the growth pressure is 100-500 torr. Specifically, when growing the InAlGaN layer, NH ₃ is introduced into the MOCVD reaction chamber as the N source; Ar or N ₂ is used as the carrier gas, TMAl is introduced as the Al source, TMIn is introduced as the In source, and TEGa is introduced as the Ga source . When growing the InN layer, NH ₃ is introduced into the MOCVD reaction chamber as the N source; Ar or N ₂ is used as the carrier gas, and TMIn is introduced as the In source.

S3: growing a third quantum well sublayer on the second quantum well sublayer;

Specifically, a P-AlGaN layer is grown in MOCVD as the third quantum well sublayer. The growth temperature of the third quantum well sublayer is 700-800° C., and the growth pressure is 100-500 torr. During growth, NH ₃ is introduced into the MOCVD reaction chamber as the N source, Cp ₂ Mg as the P-type dopant source; Ar or N ₂ is used as the carrier gas, TMAl is introduced as the Al source, and TMIn is introduced as the In source , into TEGa as Ga source.

Preferably, in one embodiment of the present invention, the third quantum well sub-layer is grown by pulse doping, that is, the Cp ₂ Mg is controlled to be fed in pulse form to periodically form the doped P-InGaN layer and non- Doped P-InGaN layer.

S250: growing an electron blocking layer on the active layer;

Specifically, Al _a Ga _1-a N layers and In _b Ga _1-b N layers are grown periodically in MOCVD as electron blocking layers. Wherein, the growth temperature of the Al _a Ga _1-a N layer is 900-1000° C., and the growth pressure is 100-500 torr. During growth, NH ₃ is fed into the MOCVD reaction chamber as the N source, N ₂ and H ₂ are used as the carrier gas, TMAl is fed as the Al source, and TMGa is fed as the Ga source. The growth temperature of the In _b Ga _1-b N layer is 900-1000° C., and the growth pressure is 100-500 torr. During growth, NH ₃ is fed into the MOCVD reaction chamber as the N source, N ₂ and H ₂ are used as the carrier gas, TMIn is fed as the In source, and TMGa is fed as the Ga source.

S260: growing a P-GaN layer on the electron blocking layer;

Specifically, the P-GaN layer is grown in MOCVD at a growth temperature of 800-1000° C. and a growth pressure of 100-300 torr. During growth, NH ₃ is fed into the MOCVD reaction chamber as N source, Cp ₂ Mg is fed as P-type dopant source; H ₂ and N ₂ are used as carrier gas, and TMGa is fed as Ga source.

The present invention is further described below with specific embodiment:

Example 1

The present embodiment provides a light emitting diode epitaxial wafer, referring to Fig. 1 and Fig. 2, which includes a substrate 1 and a buffer layer 2, a U-GaN layer 3, an N-GaN layer 4, an active Layer 5, electron blocking layer 6 and P-GaN layer 7.

Wherein, the substrate 1 is a sapphire substrate, the buffer layer 2 is an AlGaN layer with a thickness of 30nm, and the U-GaN layer 3 has a thickness of 400nm. The doping concentration of Si in the N-GaN layer 4 is 7×10 ¹⁸ cm ⁻³ , and its thickness is 2.2 μm.

Wherein, the active layer 5 includes alternately stacked quantum well layers 51 and quantum barrier layers (GaN layers, each with a thickness of 10 nm), and the number of stacking periods is 10. Each quantum well layer 51 includes a first quantum well sublayer 511 , a second quantum well sublayer 512 and a third quantum well sublayer 513 stacked in sequence.

Wherein, the first quantum well sublayer 511 is an N-InGaN layer with an In composition ratio of 0.08, a doping element of Si, a doping concentration of 7.5×10 ¹⁵ cm ⁻³ , and a thickness of 1.6 nm. The second quantum well sublayer 512 is a periodic structure formed by a plurality of alternately stacked InAlGaN layers 512a and InN layers 512b, and the number of periods is 4. In a single InAlGaN layer 512a, the In component ratio is 0.12, and the Al component ratio is 0.12. is 0.06, and its thickness is 0.6nm; in a single InN layer 512b, the proportion of In component is 0.32, and its thickness is 0.6nm. The third quantum well sublayer 513 is a P-InGaN layer with an In composition ratio of 0.08 and a thickness of 1.6nm. The doping element is Mg with a doping concentration of 6×10 ¹⁶ cm ⁻³ .

Among them, the electron blocking layer 6 is a periodic structure in which Al _a Ga _1-a N layers (a=0.12) and In _b Ga _1-b N layers (b=0.3) are alternately grown, the number of periods is 8, and a single Al _a The Ga _1-a N layer has a thickness of 6 nm, and the single In _b Ga _1-b N layer has a thickness of 1 nm. The doping element of the P-GaN layer 7 is Mg, the doping concentration is 3.5×10 ¹⁹ cm ⁻³ , and the thickness is 240 nm.

The preparation method of the light-emitting diode epitaxial wafer in this embodiment includes the following steps:

(1) Provide a substrate; load the substrate into MOCVD, and anneal at 1120°C, 400torr, and hydrogen atmosphere for 7min.

(2) Growing a buffer layer on the substrate;

Specifically, MOCVD is used to grow the AlGaN layer, the growth temperature is 620° C., and the growth pressure is 250 torr. During growth, NH ₃ is fed into the MOCVD reaction chamber as the N source; H ₂ and N ₂ are used as the carrier gas, TMAl is fed as the Al source, and TMGa is fed as the Ga source.

(3) growing a U-GaN layer on the buffer layer;

Specifically, the U-GaN layer is grown by MOCVD, the growth temperature is 1100°C, and the growth pressure is 250 torr. During the growth, NH ₃ is passed into the MOCVD reaction chamber as the N source; H ₂ and N ₂ are used as the carrier gas, and the TMGa serves as Ga source.

(4) growing N-GaN layer on U-GaN layer;

Specifically, MOCVD is used to grow the N-GaN layer, the growth temperature is 1120°C, and the growth pressure is 150torr; during growth, NH ₃ is introduced into the MOCVD reaction chamber as the N source, and SiH ₄ is introduced as the N-type dopant source; _H2 and _N2 are used as carrier gas, and TMGa is passed through as Ga source.

(5) Growing the active layer on the N-GaN layer;

Specifically, the quantum well layer and the quantum barrier layer are grown periodically in MOCVD to obtain the active layer;

Among them, the growth temperature of the quantum barrier layer is 820°C, and the growth pressure is 300torr. During the growth, _NH3 is passed into the MOCVD reaction chamber as the N source, _H2 and _N2 are used as the carrier gas, and TEGa is passed as the Ga source.

The preparation method of each quantum well layer is:

(I) growing the first quantum well sublayer;

Specifically, an N-InGaN layer is grown by MOCVD as the first quantum well sublayer. The growth temperature is 760° C., and the growth pressure is 220 torr. During growth, NH ₃ is introduced into the MOCVD reaction chamber as the N source, SiH ₄ is introduced as the N-type dopant source; N ₂ is used as the carrier gas, TMAl is introduced as the Al source, TMIn is introduced as the In source, and TEGa is used as Ga source.

(II) growing a second quantum well sublayer on the first quantum well sublayer;

Specifically, an InAlGaN layer and an InN layer are grown periodically in MOCVD as the second quantum well sublayer. The growth temperature of the second quantum well sublayer is 760° C., and the growth pressure is 220 torr. Specifically, when growing the InAlGaN layer, _NH3 is fed into the MOCVD reaction chamber as the N source; _N2 is used as the carrier gas, TMAl is fed as the Al source, TMIn is fed as the In source, and TEGa is fed as the Ga source. When growing the InN layer, NH ₃ is introduced into the MOCVD reaction chamber as the N source; N ₂ is used as the carrier gas, and TMIn is introduced as the In source.

(III) growing a third quantum well sublayer on the second quantum well sublayer;

Specifically, a P-AlGaN layer is grown in MOCVD as the third quantum well sublayer. The growth temperature of the third quantum well sublayer is 760° C., and the growth pressure is 220 torr. During growth, NH ₃ is introduced into the MOCVD reaction chamber as N source, Cp ₂ Mg is introduced as P-type dopant source; N ₂ is used as carrier gas, TMAl is introduced as Al source, TMIn is introduced as In source, and Inject TEGa as the Ga source.

(6) An electron blocking layer is grown on the active layer;

Specifically, an Al _x In _y Ga _1-xy N layer is grown by MOCVD as an electron blocking layer. The growth temperature is 960° C., and the growth pressure is 200 torr.

(7) growing a P-GaN layer on the electron blocking layer;

Specifically, Al _a Ga _1-a N layers and In _b Ga _1-b N layers are grown periodically in MOCVD as electron blocking layers. Wherein, the growth temperature of the Al _a Ga _1-a N layer is 980° C., and the growth pressure is 300 torr. During growth, NH ₃ is fed into the MOCVD reaction chamber as the N source, N ₂ and H ₂ are used as the carrier gas, TMAl is fed as the Al source, and TMGa is fed as the Ga source. The growth temperature of the In _b Ga _1-b N layer is 980° C., and the growth pressure is 300 torr. During growth, NH ₃ is fed into the MOCVD reaction chamber as the N source, N ₂ and H ₂ are used as the carrier gas, TMIn is fed as the In source, and TMGa is fed as the Ga source.

Example 2

This embodiment provides a light emitting diode epitaxial wafer, referring to Fig. 1-Fig. Layer 5, electron blocking layer 6 and P-GaN layer 7.

Wherein, the substrate 1 is a sapphire substrate, the buffer layer 2 is an AlGaN layer with a thickness of 30nm, and the U-GaN layer 3 has a thickness of 400nm. The doping concentration of Si in the N-GaN layer 4 is 7×10 ¹⁸ cm ⁻³ , and its thickness is 2.2 μm.

Wherein, the active layer 5 includes alternately stacked quantum well layers 51 and quantum barrier layers (GaN layers, each with a thickness of 10 nm), and the number of stacking periods is 10. Each quantum well layer 51 includes a first quantum well sublayer 511 , a second quantum well sublayer 512 and a third quantum well sublayer 513 stacked in sequence.

Specifically, the first quantum well sublayer 511 is a pulse-doped N-InGaN layer, that is, a periodic structure formed by a plurality of alternately stacked doped N-InGaN layers 511a and non-doped N-InGaN layers 511b . The number of periods is 4, the proportion of In in a single doped N-InGaN layer 511a is 0.08, the doping element is Si, the doping concentration is 8.8×10 ¹⁵ cm ^-3 , and the thickness is 0.2nm; a single non-doped The proportion of In in the type N-InGaN layer 511b is 0.08, and the thickness is 0.2nm.

Wherein, the second quantum well sublayer 512 is a periodic structure formed by a plurality of alternately stacked InAlGaN layers 512a and InN layers 512b, and the number of periods is 4. In a single InAlGaN layer 512a, the proportion of In is 0.12, and the proportion of Al is 0.12. The proportion is 0.06, and its thickness is 0.6nm; in a single InN layer 512b, the In component proportion is 0.35, and its thickness is 0.6nm. The third quantum well sublayer 513 is a P-InGaN layer with an In composition ratio of 0.08 and a thickness of 1.6nm. The doping element is Mg with a doping concentration of 6×10 ¹⁶ cm ⁻³ .

Among them, the electron blocking layer 6 is a periodic structure in which Al _a Ga _1-a N layers (a=0.12) and In _b Ga _1-b N layers (b=0.3) are grown alternately, the number of periods is 8, and a single Al _a The Ga _1-a N layer has a thickness of 6 nm, and the single In _b Ga _1-b N layer has a thickness of 1 nm. The doping element of the P-GaN layer 7 is Mg, the doping concentration is 3.5×10 ¹⁹ cm ⁻³ , and the thickness is 240 nm.

The preparation method of the light-emitting diode epitaxial wafer in this embodiment includes the following steps:

(1) Provide a substrate; load the substrate into MOCVD, and anneal at 1120°C, 400torr, and hydrogen atmosphere for 7min.

(2) Growing a buffer layer on the substrate;

Specifically, MOCVD is used to grow the AlGaN layer, the growth temperature is 620° C., and the growth pressure is 250 torr. During growth, NH ₃ is fed into the MOCVD reaction chamber as the N source; H ₂ and N ₂ are used as the carrier gas, TMAl is fed as the Al source, and TMGa is fed as the Ga source.

(3) growing a U-GaN layer on the buffer layer;

Specifically, the U-GaN layer is grown by MOCVD, the growth temperature is 1100°C, and the growth pressure is 250 torr. During the growth, NH ₃ is passed into the MOCVD reaction chamber as the N source; H ₂ and N ₂ are used as the carrier gas, and the TMGa serves as Ga source.

(4) growing N-GaN layer on U-GaN layer;

Specifically, MOCVD is used to grow the N-GaN layer, the growth temperature is 1120°C, and the growth pressure is 150torr; during growth, NH ₃ is introduced into the MOCVD reaction chamber as the N source, and SiH ₄ is introduced as the N-type dopant source; _H2 and _N2 are used as carrier gas, and TMGa is passed through as Ga source.

(5) Growing the active layer on the N-GaN layer;

Specifically, the quantum well layer and the quantum barrier layer are grown periodically in MOCVD to obtain the active layer;

Among them, the growth temperature of the quantum barrier layer is 820°C, and the growth pressure is 300torr. During the growth, _NH3 is passed into the MOCVD reaction chamber as the N source, _H2 and _N2 are used as the carrier gas, and TEGa is passed as the Ga source.

The preparation method of each quantum well layer is:

(I) growing the first quantum well sublayer;

Specifically, an N-InGaN layer is grown by MOCVD as the first quantum well sublayer. The growth temperature is 760° C., and the growth pressure is 220 torr. During growth, NH ₃ is introduced into the MOCVD reaction chamber as the N source, SiH ₄ is introduced as the N-type dopant source; N ₂ is used as the carrier gas, TMAl is introduced as the Al source, TMIn is introduced as the In source, and TEGa is used as Ga source.

Specifically, SiH ₄ is controlled to be fed in the form of pulses to periodically form doped N-InGaN layers and non-doped N-InGaN layers.

(II) growing a second quantum well sublayer on the first quantum well sublayer;

Specifically, an InAlGaN layer and an InN layer are grown periodically in MOCVD as the second quantum well sublayer. The growth temperature of the second quantum well sublayer is 760° C., and the growth pressure is 220 torr. Specifically, when growing the InAlGaN layer, _NH3 is fed into the MOCVD reaction chamber as the N source; _N2 is used as the carrier gas, TMAl is fed as the Al source, TMIn is fed as the In source, and TEGa is fed as the Ga source. When growing the InN layer, NH ₃ is introduced into the MOCVD reaction chamber as the N source; N ₂ is used as the carrier gas, and TMIn is introduced as the In source.

(III) growing a third quantum well sublayer on the second quantum well sublayer;

Specifically, a P-AlGaN layer is grown in MOCVD as the third quantum well sublayer. The growth temperature of the third quantum well sublayer is 760° C., and the growth pressure is 220 torr. During growth, NH ₃ is introduced into the MOCVD reaction chamber as N source, Cp ₂ Mg is introduced as P-type dopant source; N ₂ is used as carrier gas, TMAl is introduced as Al source, TMIn is introduced as In source, and Inject TEGa as the Ga source.

(6) An electron blocking layer is grown on the active layer;

Specifically, an Al _x In _y Ga _1-xy N layer is grown by MOCVD as an electron blocking layer. The growth temperature is 960° C., and the growth pressure is 200 torr.

(7) growing a P-GaN layer on the electron blocking layer;

Specifically, Al _a Ga _1-a N layers and In _b Ga _1-b N layers are grown periodically in MOCVD as electron blocking layers. Wherein, the growth temperature of the Al _a Ga _1-a N layer is 980° C., and the growth pressure is 300 torr. During growth, NH ₃ is fed into the MOCVD reaction chamber as the N source, N ₂ and H ₂ are used as the carrier gas, TMAl is fed as the Al source, and TMGa is fed as the Ga source. The growth temperature of the In _b Ga _1-b N layer is 980° C., and the growth pressure is 300 torr. During growth, NH ₃ is fed into the MOCVD reaction chamber as the N source, N ₂ and H ₂ are used as the carrier gas, TMIn is fed as the In source, and TMGa is fed as the Ga source.

Example 3

This embodiment provides a light-emitting diode epitaxial wafer, referring to Fig. 1, Fig. 2, Fig. 4, which includes a substrate 1 and a buffer layer 2, a U-GaN layer 3, and an N-GaN layer 4 sequentially arranged on the substrate 1 , active layer 5, electron blocking layer 6 and P-GaN layer 7.

Wherein, the substrate 1 is a sapphire substrate, the buffer layer 2 is an AlGaN layer with a thickness of 30nm, and the U-GaN layer 3 has a thickness of 400nm. The doping concentration of Si in the N-GaN layer 4 is 7×10 ¹⁸ cm ⁻³ , and its thickness is 2.2 μm.

Wherein, the first quantum well sublayer 511 is an N-InGaN layer with an In composition ratio of 0.08, a doping element of Si, a doping concentration of 7.5×10 ¹⁵ cm ⁻³ , and a thickness of 1.6 nm. The second quantum well sublayer 512 is a periodic structure formed by a plurality of alternately stacked InAlGaN layers 512a and InN layers 512b, and the number of periods is 4. In a single InAlGaN layer 512a, the In component ratio is 0.12, and the Al component ratio is 0.12. is 0.06, and its thickness is 0.6nm; in a single InN layer 512b, the proportion of In component is 0.32, and its thickness is 0.6nm. The third quantum well sublayer 513 is a P-InGaN layer with an In composition ratio of 0.08 and a thickness of 1.6nm. The doping element is Mg with a doping concentration of 6×10 ¹⁶ cm ⁻³ .

Wherein, the third quantum well sublayer 513 is a pulse-doped P-InGaN layer, that is, a periodic structure formed by a plurality of alternately stacked doped P-InGaN layers 513a and undoped P-InGaN layers 513b, The number of cycles is 4. Wherein, the proportion of In component in the single doped P-InGaN layer 513a is 0.08, the thickness is 0.2nm, the doping element is Mg, and the doping concentration is 8×10 ¹⁶ cm ⁻³ . The proportion of In in the single non-doped P-InGaN layer 513b is 0.08, and the thickness is 0.2nm.

Among them, the electron blocking layer 6 is a periodic structure in which Al _a Ga _1-a N layers (a=0.12) and In _b Ga _1-b N layers (b=0.3) are grown alternately, the number of periods is 8, and a single Al _a The Ga _1-a N layer has a thickness of 6 nm, and the single In _b Ga _1-b N layer has a thickness of 1 nm. The doping element of the P-GaN layer 7 is Mg, the doping concentration is 3.5×10 ¹⁹ cm ⁻³ , and the thickness is 240 nm.

The preparation method of the light-emitting diode epitaxial wafer in this embodiment includes the following steps:

(1) Provide a substrate; load the substrate into MOCVD, and anneal at 1120°C, 400torr, and hydrogen atmosphere for 7min.

(2) growing a buffer layer on the substrate;

Specifically, MOCVD is used to grow the AlGaN layer, the growth temperature is 620° C., and the growth pressure is 250 torr. During growth, NH ₃ is fed into the MOCVD reaction chamber as the N source; H ₂ and N ₂ are used as the carrier gas, TMAl is fed as the Al source, and TMGa is fed as the Ga source.

(3) growing a U-GaN layer on the buffer layer;

Specifically, the U-GaN layer is grown by MOCVD, the growth temperature is 1100°C, and the growth pressure is 250 torr. During the growth, NH ₃ is passed into the MOCVD reaction chamber as the N source; H ₂ and N ₂ are used as the carrier gas, and the TMGa serves as Ga source.

(4) growing N-GaN layer on U-GaN layer;

Specifically, MOCVD is used to grow the N-GaN layer, the growth temperature is 1120°C, and the growth pressure is 150torr; during growth, NH ₃ is introduced into the MOCVD reaction chamber as the N source, and SiH ₄ is introduced as the N-type dopant source; _H2 and _N2 are used as carrier gas, and TMGa is passed through as Ga source.

(5) Growing the active layer on the N-GaN layer;

Specifically, the quantum well layer and the quantum barrier layer are grown periodically in MOCVD to obtain the active layer;

Among them, the growth temperature of the quantum barrier layer is 820°C, and the growth pressure is 300torr. During the growth, _NH3 is passed into the MOCVD reaction chamber as the N source, _H2 and _N2 are used as the carrier gas, and TEGa is passed as the Ga source.

The preparation method of each quantum well layer is:

(I) growing the first quantum well sublayer;

Specifically, an N-InGaN layer is grown by MOCVD as the first quantum well sublayer. The growth temperature is 760° C., and the growth pressure is 220 torr. During growth, NH ₃ is introduced into the MOCVD reaction chamber as the N source, SiH ₄ is introduced as the N-type dopant source; N ₂ is used as the carrier gas, TMAl is introduced as the Al source, TMIn is introduced as the In source, and TEGa is used as Ga source.

(II) growing a second quantum well sublayer on the first quantum well sublayer;

Specifically, an InAlGaN layer and an InN layer are grown periodically in MOCVD as the second quantum well sublayer. The growth temperature of the second quantum well sublayer is 760° C., and the growth pressure is 220 torr. Specifically, when growing the InAlGaN layer, _NH3 is fed into the MOCVD reaction chamber as the N source; _N2 is used as the carrier gas, TMAl is fed as the Al source, TMIn is fed as the In source, and TEGa is fed as the Ga source. When growing the InN layer, NH ₃ is introduced into the MOCVD reaction chamber as the N source; N ₂ is used as the carrier gas, and TMIn is introduced as the In source.

(III) growing a third quantum well sublayer on the second quantum well sublayer;

Specifically, a P-AlGaN layer is grown in MOCVD as the third quantum well sublayer. The growth temperature of the third quantum well sublayer is 760° C., and the growth pressure is 220 torr. During growth, NH ₃ is introduced into the MOCVD reaction chamber as N source, Cp ₂ Mg is introduced as P-type dopant source; N ₂ is used as carrier gas, TMAl is introduced as Al source, TMIn is introduced as In source, and Inject TEGa as the Ga source.

Specifically, Cp ₂ Mg is controlled to be fed in a pulse form to periodically form a doped P-InGaN layer and a non-doped P-InGaN layer.

(6) An electron blocking layer is grown on the active layer;

Specifically, an Al _x In _y Ga _1-xy N layer is grown by MOCVD as an electron blocking layer. The growth temperature is 960° C., and the growth pressure is 200 torr.

(7) growing a P-GaN layer on the electron blocking layer;

Specifically, Al _a Ga _1-a N layers and In _b Ga _1-b N layers are grown periodically in MOCVD as electron blocking layers. Wherein, the growth temperature of the Al _a Ga _1-a N layer is 980° C., and the growth pressure is 300 torr. During growth, NH ₃ is fed into the MOCVD reaction chamber as the N source, N ₂ and H ₂ are used as the carrier gas, TMAl is fed as the Al source, and TMGa is fed as the Ga source. The growth temperature of the In _b Ga _1-b N layer is 980° C., and the growth pressure is 300 torr. During growth, NH ₃ is fed into the MOCVD reaction chamber as the N source, N ₂ and H ₂ are used as the carrier gas, TMIn is fed as the In source, and TMGa is fed as the Ga source.

Example 4

The present embodiment provides a light-emitting diode epitaxial wafer, referring to Fig. 1-Fig. Layer 5, electron blocking layer 6 and P-GaN layer 7.

Wherein, the substrate 1 is a sapphire substrate, the buffer layer 2 is an AlGaN layer with a thickness of 30nm, and the U-GaN layer 3 has a thickness of 400nm. The doping concentration of Si in the N-GaN layer 4 is 7×10 ¹⁸ cm ⁻³ , and its thickness is 2.2 μm.

Wherein, the active layer 5 includes alternately stacked quantum well layers 51 and quantum barrier layers (GaN layers, each with a thickness of 10 nm), and the number of stacking periods is 10. Each quantum well layer 51 includes a first quantum well sublayer 511 , a second quantum well sublayer 512 and a third quantum well sublayer 513 stacked in sequence.

Specifically, the first quantum well sublayer 511 is a pulse-doped N-InGaN layer, that is, a periodic structure formed by a plurality of alternately stacked doped N-InGaN layers 511a and non-doped N-InGaN layers 511b . The number of periods is 4, the proportion of In in a single doped N-InGaN layer 511a is 0.08, the doping element is Si, the doping concentration is 8.8×10 ¹⁵ cm ^-3 , and the thickness is 0.2nm; a single non-doped The proportion of In in the type N-InGaN layer 511b is 0.08, and the thickness is 0.2nm.

Wherein, the second quantum well sublayer 512 is a periodic structure formed by a plurality of alternately stacked InAlGaN layers 512a and InN layers 512b, and the number of periods is 4. In a single InAlGaN layer 512a, the proportion of In is 0.12, and the proportion of Al is 0.12. The proportion is 0.06, and its thickness is 0.6nm; in a single InN layer 512b, the In component proportion is 0.35, and its thickness is 0.6nm.

Wherein, the third quantum well sublayer 513 is a pulse-doped P-InGaN layer, that is, a periodic structure formed by a plurality of alternately stacked doped P-InGaN layers 513a and undoped P-InGaN layers 513b, The number of cycles is 4. Wherein, the proportion of In component in the single doped P-InGaN layer 513a is 0.08, the thickness is 0.2nm, the doping element is Mg, and the doping concentration is 8×10 ¹⁶ cm ⁻³ . The proportion of In in the single non-doped P-InGaN layer 513b is 0.08, and the thickness is 0.2nm.

Among them, the electron blocking layer 6 is a periodic structure in which Al _a Ga _1-a N layers (a=0.12) and In _b Ga _1-b N layers (b=0.3) are alternately grown, the number of periods is 8, and a single Al _a The Ga _1-a N layer has a thickness of 6 nm, and the single In _b Ga _1-b N layer has a thickness of 1 nm. The doping element of the P-GaN layer 7 is Mg, the doping concentration is 3.5×10 ¹⁹ cm ⁻³ , and the thickness is 240 nm.

The preparation method of the light-emitting diode epitaxial wafer in this embodiment includes the following steps:

(1) Provide a substrate; load the substrate into MOCVD, and anneal at 1120°C, 400torr, and hydrogen atmosphere for 7min.

(2) Growing a buffer layer on the substrate;

Specifically, MOCVD is used to grow the AlGaN layer, the growth temperature is 620° C., and the growth pressure is 250 torr. During growth, NH ₃ is fed into the MOCVD reaction chamber as the N source; H ₂ and N ₂ are used as the carrier gas, TMAl is fed as the Al source, and TMGa is fed as the Ga source.

(3) growing a U-GaN layer on the buffer layer;

Specifically, the U-GaN layer is grown by MOCVD, the growth temperature is 1100°C, and the growth pressure is 250 torr. During the growth, NH ₃ is passed into the MOCVD reaction chamber as the N source; H ₂ and N ₂ are used as the carrier gas, and the TMGa serves as Ga source.

(4) growing N-GaN layer on U-GaN layer;

Specifically, MOCVD is used to grow the N-GaN layer, the growth temperature is 1120°C, and the growth pressure is 150torr; during growth, NH ₃ is introduced into the MOCVD reaction chamber as the N source, and SiH ₄ is introduced as the N-type dopant source; _H2 and _N2 are used as carrier gas, and TMGa is passed through as Ga source.

(5) Growing the active layer on the N-GaN layer;

Specifically, the quantum well layer and the quantum barrier layer are grown periodically in MOCVD to obtain the active layer;

Among them, the growth temperature of the quantum barrier layer is 820°C, and the growth pressure is 300torr. During the growth, _NH3 is passed into the MOCVD reaction chamber as the N source, _H2 and _N2 are used as the carrier gas, and TEGa is passed as the Ga source.

The preparation method of each quantum well layer is:

(I) growing the first quantum well sublayer;

Specifically, an N-InGaN layer is grown by MOCVD as the first quantum well sublayer. The growth temperature is 760° C., and the growth pressure is 220 torr. During growth, NH ₃ is introduced into the MOCVD reaction chamber as the N source, SiH ₄ is introduced as the N-type dopant source; N ₂ is used as the carrier gas, TMAl is introduced as the Al source, TMIn is introduced as the In source, and TEGa is used as Ga source.

Specifically, SiH ₄ is controlled to be fed in the form of pulses to periodically form doped N-InGaN layers and non-doped N-InGaN layers.

(II) growing a second quantum well sublayer on the first quantum well sublayer;

Specifically, an InAlGaN layer and an InN layer are grown periodically in MOCVD as the second quantum well sublayer. The growth temperature of the second quantum well sublayer is 760° C., and the growth pressure is 220 torr. Specifically, when growing the InAlGaN layer, _NH3 is fed into the MOCVD reaction chamber as the N source; _N2 is used as the carrier gas, TMAl is fed as the Al source, TMIn is fed as the In source, and TEGa is fed as the Ga source. When growing the InN layer, NH ₃ is introduced into the MOCVD reaction chamber as the N source; N ₂ is used as the carrier gas, and TMIn is introduced as the In source.

(III) growing a third quantum well sublayer on the second quantum well sublayer;

Specifically, a P-AlGaN layer is grown in MOCVD as the third quantum well sublayer. The growth temperature of the third quantum well sublayer is 760° C., and the growth pressure is 220 torr. During growth, NH ₃ is introduced into the MOCVD reaction chamber as N source, Cp ₂ Mg is introduced as P-type dopant source; N ₂ is used as carrier gas, TMAl is introduced as Al source, TMIn is introduced as In source, and Inject TEGa as the Ga source.

Specifically, Cp ₂ Mg is controlled to be fed in a pulse form to periodically form a doped P-InGaN layer and a non-doped P-InGaN layer.

(6) An electron blocking layer is grown on the active layer;

Specifically, an Al _x In _y Ga _1-xy N layer is grown by MOCVD as an electron blocking layer. The growth temperature is 960° C., and the growth pressure is 200 torr.

(7) growing a P-GaN layer on the electron blocking layer;

Specifically, Al _a Ga _1-a N layers and In _b Ga _1-b N layers are grown periodically in MOCVD as electron blocking layers. Wherein, the growth temperature of the Al _a Ga _1-a N layer is 980° C., and the growth pressure is 300 torr. During growth, NH ₃ is fed into the MOCVD reaction chamber as the N source, N ₂ and H ₂ are used as the carrier gas, TMAl is fed as the Al source, and TMGa is fed as the Ga source. The growth temperature of the In _b Ga _1-b N layer is 980° C., and the growth pressure is 300 torr. During growth, NH ₃ is fed into the MOCVD reaction chamber as the N source, N ₂ and H ₂ are used as the carrier gas, TMIn is fed as the In source, and TMGa is fed as the Ga source.

Comparative example 1

This comparative example provides a light-emitting diode epitaxial wafer, which is different from Example 1 in that the quantum well layer is an InGaN layer, the In composition ratio is 0.25, the growth temperature is 790° C., and the growth pressure is 200 torr.

Comparative example 2

This comparative example provides a light-emitting diode epitaxial wafer, which is different from Embodiment 1 in that the quantum well layer 51 does not include the first quantum well sublayer 511 and the third quantum well sublayer 513 . Correspondingly, in the preparation method, the preparation steps of the above two layers are not set, and the rest are the same as in Example 1.

Comparative example 3

This comparative example provides a light-emitting diode epitaxial wafer, which differs from the first embodiment in that the quantum well layer 51 does not include the first quantum well sublayer 511 . Correspondingly, in the preparation method, the preparation step of this layer is not set, and the rest are the same as in Example 1.

Comparative example 4

This comparative example provides a light emitting diode epitaxial wafer, which is different from the first embodiment in that the quantum well layer 51 does not include the third quantum well sublayer 513 . Correspondingly, in the preparation method, the preparation step of this layer is not set, and the rest are the same as in Example 1.

Comparative example 5

This comparative example provides a light emitting diode epitaxial wafer, which is different from the first embodiment in that the quantum well layer 51 does not include the third quantum well sublayer 513 . Correspondingly, in the preparation method, the preparation step of this layer is not set, and the rest are the same as in Example 1.

The light-emitting diode epitaxial wafers obtained in Examples 1-4 and Comparative Examples 1-5 were tested for brightness, and the specific results were as follows:

As can be seen from the table, when the traditional quantum well layer (comparative example 1) is changed to the quantum well layer structure in the present invention, the luminous efficiency is increased from 188.5mW to 193.6mW, indicating that the quantum well layer in the present invention can Effectively improve luminous efficiency. In addition, it can be seen from the comparison between Example 1 and Comparative Examples 2-4 that when the quantum well layer structure in the present application is changed, it is difficult to effectively improve the luminous efficiency.

The above is the preferred embodiment of the invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications are also considered as protection scope of the present invention.

Claims (9)

1. A light-emitting diode epitaxial wafer, comprising a substrate and a buffer layer, a U-GaN layer, an N-GaN layer, an active layer, an electron blocking layer and a P-GaN layer that are successively arranged on the substrate, the The active layer includes a plurality of alternately stacked quantum well layers and quantum barrier layers; it is characterized in that the quantum well layer includes sequentially stacked first quantum well sublayers, second quantum well sublayers and third quantum well sublayers ; Wherein, the first quantum well sublayer is an N-InGaN layer, the second quantum well sublayer is a periodic structure formed by a plurality of alternately stacked InAlGaN layers and InN layers, and the third quantum well sublayer is P-InGaN layer; Wherein, the number of periods of the second quantum well sublayer is 2-6, the thickness of a single InAlGaN layer is 0.1-1nm, and the thickness of a single InN layer is 0.1-1nm; the proportion of Al components in the InAlGaN layer is 0.02-0.1, the proportion of the In component is 0.1-0.2, and the proportion of the In component in the InN layer is 0.2-0.5. 2. The light-emitting diode epitaxial wafer as claimed in claim 1, wherein the ratio of the In component in the first quantum well sublayer is 0.05-0.1, and the doping element of the first quantum well sublayer For Si, the doping concentration is 5×10 ¹⁵ -1×10 ¹⁶ cm ^-3 . 3. The light-emitting diode epitaxial wafer as claimed in claim 1, wherein the proportion of In composition in the third quantum well sublayer is 0.05-0.1, and the doping element of the third quantum well sublayer Mg, the doping concentration is 5×10 ¹⁵ -1×10 ¹⁷ cm ^-3 . 4. The light-emitting diode epitaxial wafer according to claim 1, wherein the thickness of the first quantum well sublayer is 0.3-4 nm, and the thickness of the third quantum well sublayer is 0.3-4 nm. 5. The light-emitting diode epitaxial wafer according to claim 1, wherein the first quantum well sublayer is a pulse-doped N-InGaN layer, which is a plurality of alternately stacked doped N-InGaN layers A periodic structure formed with an undoped N-InGaN layer, the number of periods is 2-6; Wherein, the thickness of a single doped N-InGaN layer is 0.1-0.3 nm, and the thickness of a single non-doped N-InGaN layer is 0.1-0.3 nm; The ratio of the In component in the InN layer is 0.3-0.5. 6. The light-emitting diode epitaxial wafer according to claim 1, wherein the third quantum well sublayer is a pulse-doped P-InGaN layer, which is a plurality of alternately stacked doped P-InGaN layers A periodic structure formed with an undoped P-InGaN layer, the number of periods is 2-6; The thickness of a single doped P-InGaN layer is 0.1-0.3nm, and the thickness of a single non-doped P-InGaN layer is 0.1-0.3nm. 7. A method for preparing a light-emitting diode epitaxial wafer, for preparing the light-emitting diode epitaxial wafer according to any one of claims 1-6, characterized in that, comprising: Provide a substrate on which a buffer layer, a U-GaN layer, an N-GaN layer, an active layer, an electron blocking layer, and a P-GaN layer are sequentially grown; the active layer includes a plurality of alternately stacked quantum a well layer and a quantum barrier layer, the quantum well layer includes a first quantum well sublayer, a second quantum well sublayer and a third quantum well sublayer stacked in sequence; Wherein, the first quantum well sublayer is an N-InGaN layer, the second quantum well sublayer is a periodic structure formed by a plurality of alternately stacked InAlGaN layers and InN layers, and the third quantum well sublayer is P-InGaN layer; The growth temperature of the first quantum well sublayer, the second quantum well sublayer and the third quantum well sublayer are all 700-800° C., and the growth pressure is 100-500 torr. 8. the preparation method of light-emitting diode epitaxial wafer as claimed in claim 7 is characterized in that, the carrier gas adopted during the growth of the first quantum well sublayer, the second quantum well sublayer and the third quantum well sublayer nitrogen or argon. 9. A light emitting diode, characterized by comprising the light emitting diode epitaxial wafer according to any one of claims 1-6.

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