A quantum well LED with AlGaN / InGaN superlattice well layer and a preparation method thereof

Abstract

A quantum well LED with AlGaN / InGaN superlattice well layer and a preparation method thereof belong to the technical field of semiconductor light emitting devices. The quantum well LED is composed of a substrate, a nucleation layer, a GaN undoped layer, an n-type GaN layer, a multi-quantum well active region, an electron blocking layer, a p-type GaN layer, a current spreading layer, a passivation layer and an electrode. The multi-quantum well active region is a periodic well layer / barrier layer structure, the barrier layer is a GaN layer, the well layer is an Al x Ga 1‑x N layer and an In y Ga 1‑y N layer, and the well layer and the barrier layer are periodically arranged in a superlattice structure. The composition of the well layer superlattice is adjusted to realize polarization matching with the GaN barrier layer, so as to reduce the polarization electric field intensity in the well layer and improve the light emitting efficiency of the device. Compared with the traditional InGaN well layer, the thickness of the InGaN light emitting layer in the well layer superlattice is thinner, the quantum confinement Stark effect is weaker, and the light emitting wavelength stability of the device can be further improved.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor light-emitting device technology, specifically relating to a quantum well LED with an AlGaN / InGaN superlattice well layer and its fabrication method. Background Technology

[0002] Group III nitride semiconductors possess direct bandgap structures and offer advantages such as a wide bandgap coverage and stable physical and chemical properties, making them widely used in the fabrication of optoelectronic devices such as light-emitting diodes (LEDs) and laser diodes (LDs). However, Group III nitride semiconductors exhibit strong polarization effects, generating polarization electric fields on the order of MV / cm in the quantum well of the active region of optoelectronic devices. This causes a significant drift in the emission wavelength of the device with changes in the driving voltage, affecting the wavelength stability of the device. Furthermore, the strong polarization effect also hinders further improvements in the performance of nitride optoelectronic devices.

[0003] Using AlGaN / InGaN superlattices as barriers in quantum well structures has proven to be an effective method for reducing the polarization electric field intensity of quantum wells. This is because, by controlling the composition of the superlattice (Al and In composition), polarization matching between the superlattice barrier layer and the InGaN well layer can be achieved, thereby effectively reducing the polarization electric field intensity in the InGaN well layer and improving the wavelength stability of the device. However, compared with traditional GaN barriers, the high-quality growth of superlattice barriers is more difficult, which also affects the growth quality of the InGaN well layer, resulting in lower luminous efficiency of the device. Furthermore, when changing the In composition of the InGaN well layer to adjust the emission wavelength of the device, the composition of the superlattice barrier layer also needs to be adjusted accordingly. This means that the growth process of the superlattice barrier layer needs to be re-optimized, increasing the complexity of device fabrication. Summary of the Invention

[0004] This invention proposes a quantum well LED with an AlGaN / InGaN superlattice well layer and its fabrication method. In the quantum well LED of this invention, an AlGaN / InGaN superlattice is used as the well layer, and GaN is used as the barrier layer.

[0005] The present invention describes a quantum well LED with an AlGaN / InGaN superlattice well layer (see appendix). Figure 1(and the attached drawings), the quantum well LED structure, from bottom to top, successively consists of a substrate 1, a nucleation layer 2, an undoped GaN layer 3, an n-type GaN layer 4, a multi-quantum well active region 5, an electron blocking layer 6, a p-type GaN layer 7, and a current spreading layer 8; a stepped structure with sidewalls is formed between the n-type GaN layer 4 and the current spreading layer 8, a passivation layer 9 is prepared on the n-type GaN layer 4, the current spreading layer 8 and the sidewalls, electrode windows are respectively opened in the passivation layer 9 above the current spreading layer 8 and the n-type GaN layer 4, and a p-type electrode 10 and an n-type electrode 10' are respectively prepared in the electrode windows.

[0006] Further, the substrate 1 can be sapphire, carbon face or carbon face SiC, gallium face or nitrogen face GaN, or other single crystal substrates that can be used for the epitaxial growth of group III nitride materials; the nucleation layer 2 is a GaN or AlN thin film with a thickness of 10 - 200 nm; the undoped GaN layer 3 is an unintentionally doped GaN layer with a thickness of 200 nm - 10 μm; the n-type GaN layer 4 is a Si-doped GaN layer with a doping concentration of 10 , x , 19 , -3 , 19 , -3 , m , 1-x ,

[0006] , 1-m , 18 , 1-y , -3 , x , 1-x , y ,

[0007] , Figure 2 cm -3 magnitude, with a thickness of 1 - 3 μm; the electron blocking layer 6 is a Mg-doped p-type Al m Ga 1-m N layer, where 0.1 ≤ m ≤ 0.3, with a doping concentration of 10 19 cm -3 magnitude, with a thickness of 10 - 50 nm; the p-type GaN layer 7 is a Mg-doped GaN layer with a doping concentration of 10 19 cm -3 magnitude, with a thickness of 100 - 200 nm; the current spreading layer 8 is indium tin oxide with a thickness of 20 - 300 nm; the passivation layer 9 is SiO2 with a thickness of 500 nm - 2 μm; the p-type electrode 10 and the n-type electrode 10' are binary alloy composite materials such as Ti-Au, ternary alloy composite materials such as Ti-Al-Au, or quaternary alloy composite materials such as Ti-Al-Ni-Au, Ti-Al-Ti-Au, etc., with a thickness of 60 - 300 nm.

[0007] Further, the multi-quantum well active region 5 is a periodic well layer / barrier layer structure (see the attached Figure 2 drawings and the attached drawing description), and the number of periods is between 1 and 15; among them, the barrier layer 11 is a GaN layer with a thickness of 2 - 15 nm; the well layer is a superlattice structure in which Al x Ga 1-x N layer 12 and In y Ga 1-y N layer 13 are periodically alternated, and the number of periods is between 1 and 10, where 0 < x < 1, 0 < y < 1; in each period of the well layer, Al x Ga 1-xThe thickness of layer N12 is a nm (0.5 ≤ a ≤ 2), In y Ga 1-y The thickness of layer N13 is b nm (0.5≤b≤2).

[0008] Furthermore, the quantum well LED structure can be a nitrogen-polarized LED structure or a metal-polarized LED structure; nitrogen-polarized LEDs are epitaxially grown on sapphire substrates treated with high-temperature nitriding at ≥900 ℃, and metal-polarized LEDs are epitaxially grown on sapphire substrates treated with low-temperature nitriding at ≤700 ℃; metal-polarized LEDs are epitaxially grown on silicon-faced SiC substrates, and nitrogen-polarized LEDs are epitaxially grown on carbon-faced SiC substrates; metal-polarized LEDs are epitaxially grown on gallium-faced GaN substrates, and nitrogen-polarized LEDs are epitaxially grown on nitrogen-faced GaN substrates.

[0009] The fabrication method of a quantum well LED with an AlGaN / InGaN superlattice well layer, as described above, comprises the following steps:

[0010] 1) Metal-organic chemical vapor deposition (MOCVD) was used to sequentially epitaxially grow a nucleation layer 2, an undoped GaN layer 3, an n-type GaN layer 4, a multi-quantum-well active region 5, an electron-blocking layer 6, and a p-type GaN layer 7 on substrate 1. Nitrogen was used as the carrier gas during the growth of the multi-quantum-well active region 5, while hydrogen was used as the carrier gas for the remaining parts. Trimethylaluminum (TMA), trimethylindium (TMIn), and trimethylgallium (TMGa) were used as Al, In, and Ga sources, respectively, and high-purity ammonia was used as the N source. Silane was used as the n-type dopant source, and magnesium pyrocene was used as the p-type dopant source. The growth temperature of the nucleation layer 2 was 530–550 °C, the growth pressure was 100–400 mbar, and the growth thickness was 10–200 nm. The growth temperature of the undoped GaN layer 3 was 1000–1100 °C, the growth pressure was 100–400 mbar, and the growth thickness was 200 nm–10 nm. μm; the growth temperature of the n-type GaN layer 4 is 1000~1100 ℃, the growth pressure is 100~400 mbar, the growth thickness is 1~3 μm, and the n-type doping concentration is 10 μm. 18 cm -3 In the multi-quantum-well active region 5, the GaN barrier layer 11 is grown at a temperature of 800–900 °C, a growth pressure of 100–400 mbar, and a thickness of 2–15 nm. The AlGaN / InGaN superlattice well layer is grown using a pulsed method. Within one pulse cycle, ammonia gas is continuously introduced, followed by sequential introduction of TMA and TMGa to grow Al. x Ga 1-x N layers 12, then TMI and TMGa are sequentially introduced to grow In. y Ga1-y Layer N, 13, cycling 1-10 times according to this sequence pattern, with a growth temperature of 650-850 ℃ and a growth pressure of 100-400 mbar, Al x Ga 1-x N layer 12 and In y Ga 1-y The thickness of N layer 13 is 0.5~2 nm, and the number of well / barrier layers in the multi-quantum-well active region 5 is 1~15. Al x Ga 1-x N layer 12 and In y Ga 1-y The composition of N-layer 13 can be controlled by adjusting the growth temperature and the amount and duration of source injection in the pulsed growth method; the growth temperature of electron blocking layer 6 is 900~1000 ℃, the growth pressure is 100~400 mbar, the growth thickness is 10~50 nm, and the p-type doping concentration is 10. 19 cm -3 The Al composition of electron blocking layer 6 is controlled by adjusting the TMA source flux; the growth temperature of p-type GaN layer 7 is 900~1000 ℃, the growth pressure is 100~400 mbar, the growth thickness is 100~200 nm, and the p-type doping concentration is 10. 19 cm -3 Magnitude;

[0011] 2) A transparent indium tin oxide (ITO) current spreading layer 8 with a thickness of 20–300 nm is prepared on the p-type GaN layer 7 by magnetron sputtering. To prepare the n-type electrode 10' on the n-type GaN layer 4, the current spreading layer 8 needs to be etched down to the n-type GaN layer 4 using methods such as inductively coupled plasma (ICP) etching, resulting in exposed n-type GaN layer 4 mesa surfaces. The size of the etched area is determined according to actual needs. Then, a SiO2 passivation layer 9 with a thickness of 500 nm is deposited on the current spreading layer 8, the etched sidewalls, and the exposed n-type GaN layer 4 mesa surfaces using plasma-enhanced chemical vapor deposition (PECVD) to reduce etching defects. μm; finally, the SiO2 passivation layer 9 is etched by reactive ion etching (RIE) technology to form an electrode window, exposing the current spreading layer 8 and the n-type GaN layer 4. Then, p-type electrode 10 and n-type electrode 10' with a thickness of 60~300 nm are prepared on the exposed current spreading layer 8 and the exposed n-type GaN layer 4 by thermal evaporation or electron beam evaporation, thereby obtaining the quantum well LED with AlGaN / InGaN superlattice well layer.

[0012] Effects and benefits of the present invention: In the LED structure described in the present invention, an AlGaN / InGaN superlattice well layer is used, and GaN is used as the barrier layer. This structure can achieve polarization matching with the GaN barrier layer by adjusting the composition of the well layer superlattice, thereby reducing the polarization electric field intensity in the well layer and improving the device wavelength stability. More importantly, this device structure has the following advantages: (1) Based on the GaN barrier layer, it is more conducive to improving the crystal quality of the well layer superlattice, thereby improving the device luminous efficiency; (2) To adjust the quantum well emission wavelength, only the composition of the well layer superlattice needs to be adjusted, without adjusting the GaN barrier layer. Moreover, after the composition of the InGaN layer in the well layer superlattice is determined (i.e., after the emission wavelength of the well layer is determined), only the Al composition of the AlGaN layer in the well layer superlattice needs to be adjusted to achieve lattice matching between the well layer superlattice and the barrier layer GaN, making the device fabrication simpler; (3) Compared with the traditional InGaN well layer, the InGaN emission layer in the well layer superlattice is thinner and the quantum confinement Stark effect is weaker, which can further improve the device emission wavelength stability. Attached Figure Description

[0013] Figure 1 : A schematic diagram of the quantum well LED with AlGaN / InGaN superlattice potential well described in this invention;

[0014] Figure 2 : A schematic diagram of a single quantum well structure with an AlGaN / InGaN superlattice potential well as described in this invention;

[0015] Figure 3 Electroluminescence spectra of quantum well LEDs with AlGaN / InGaN superlattice potential wells prepared in Example 1 at different current densities;

[0016] Figure 4 The curves showing the relationship between the emission wavelength of the quantum well LED with AlGaN / InGaN superlattice potential well prepared in Example 1 and the conventional InGaN / GaN quantum well LED prepared in Comparative Example 1 as a function of injection current density are shown.

[0017] Figure 5 Normalized external quantum efficiency plots of the LEDs prepared in Example 1 and Comparative Example 1 show that the efficiency decay of the quantum well LED with AlGaN / InGaN superlattice potential well is weaker. Detailed Implementation

[0018] Example 1

[0019] 1) Using the MOCVD method, the sapphire substrate 1 was first subjected to a low-temperature nitriding treatment at 540 °C for 180 s. Then, GaN nucleation layer 2, GaN layer 3, and n-type GaN layer 4 were sequentially epitaxially grown on substrate 1. Subsequently, the temperature was lowered to grow a multi-quantum-well active region 5, followed by a temperature increase to grow a p-type AlGaN electron-blocking layer 6 and a p-type GaN layer 7. Nitrogen was used as the carrier gas during the growth of the multi-quantum-well active region 5, while hydrogen was used as the carrier gas for the remaining regions. Group III sources included TMAl, TMIn, and TMGa; Group V sources used high-purity ammonia (NH3); n-type doping sources used silane; and p-type doping sources used magnesia-dicerocene. The nucleation layer 2 was grown at 540 °C under a growth pressure of 200 mbar and had a thickness of 40 nm. The growth temperature of the undoped GaN layer 3 and the n-type GaN layer 4 was 1050 ℃, the growth pressure was 200 mbar, the thickness was 3 μm, and the n-type doping concentration of the n-type GaN layer was 5 × 10⁻⁶. 18 cm -3 .

[0020] In the multi-quantum-well active region 5, the GaN barrier layer was grown at a temperature of 820 °C and a growth pressure of 400 mbar. The flow rates of TMGa and NH3 were 2.9 μmol / min and 233 mmol / min, respectively, with a thickness of 12 nm. The AlGaN / InGaN superlattice potential well was grown using a pulsed method. Within one pulse cycle, NH3 was continuously introduced, first TMAl and TMGa were introduced sequentially to grow the AlGaN layer, with introduction times of 2 s and 6 s, respectively. Then, TMI and TMGa were introduced sequentially to grow the InGaN layer, with introduction times of 6 s and 6 s, respectively. This sequential pattern was repeated for two cycles. The superlattice potential well was grown at a temperature of 720 °C and a growth pressure of 200 mbar. During AlGaN layer growth, the flow rates of TMAl, TMGa, and NH3 were 2.14 μmol / min, 17.3 μmol / min, and 44.6 μmol / min, respectively. The flow rates of TMI, TEGa, and NH3 during InGaN layer growth were 6.8 μmol / min, 2.9 μmol / min, and 233 mmol / min, respectively. The thickness of both AlGaN and InGaN layers was 1.1 nm. The Al composition (x) in the AlGaN layer was 0.16, and the In composition (y) in the InGaN layer was 0.10. The number of periods in the AlGaN / InGaN superlattice well layer was 2. The growth temperature of the GaN barrier layer was 820 ℃, the growth pressure was 400 mbar, and the flow rates of TEGa and NH3 during growth were 2.9 μmol / min and 233 mmol / min, respectively. The thickness was 12 nm. The number of periods in the GaN barrier / superlattice well layer in the multi-quantum well active region 5 was 2. The p-type AlGaN electron blocking layer 6 has an Al composition m of 0.3, a growth temperature of 940 ℃, a growth pressure of 200 mbar, and TMAl, TMGa, and NH3 flow rates of 13.5 μmol / min, 31.4 μmol / min, and 233 mmol / min, respectively. It has a thickness of 20 nm and a p-type doping concentration of 5 × 10⁻⁶. 19 cm -3 The p-type GaN layer 7 was grown at a temperature of 940 ℃, a growth pressure of 200 mbar, a thickness of 150 nm, and a p-type doping concentration of 5 × 10⁻⁶. 19 cm -3 .

[0021] 2) An indium tin oxide (ITO) current spreading layer 8 was fabricated on the p-type GaN layer 7 by magnetron sputtering. The target-LED device spacing was 60 mm, the tray rotation speed was set to 20 r / min, the sputtering RF power was 100 W, the temperature was 100 ℃, and the thickness of the sputtered ITO current spreading layer 8 was 90 nm. To fabricate an n-type electrode 10' on the n-type GaN layer 4, a 500 μm × 500 μm current spreading layer 8 region was etched onto the n-type GaN layer 4 using inductively coupled plasma (ICP) etching technology. Boron chloride and chlorine gas with a gas flow ratio of 1:9 were used, and the electrode power was 100 W, resulting in the exposed mesa of the n-type GaN layer 4. A SiO2 passivation layer 9 was prepared on the indium tin oxide current spread layer 8, the etched sidewalls, and the n-type GaN layer 4 using PECVD. During deposition, SiH4 was used as the Si source at a flow rate of 15 μmol / min, and oxygen was used as the O source at a flow rate of 1.5 μmol / min. The deposition pressure was 100 mbar, the temperature was 250 °C, and the thickness was 1 μm. Part of the SiO2 passivation layer 9 above the current spread layer 8 and the n-type GaN layer 4 was removed using reactive ion etching (RIE) to obtain the electrode windows for the p-type and n-type regions. A gas flow rate ratio of CF4 to CHF3 of 10:1 was used, and the RF power was 300 W. A p-type electrode 10 and an n-type electrode 10' made of Ti / Al / Ti / Au were fabricated on the electrode windows of the current spreading layer 8 and the n-type GaN layer 4 using an electron beam evaporation method. The thickness of each layer was 260 nm, with thicknesses of 40 nm, 150 nm, 20 nm, and 50 nm, respectively. The evaporation sources were Ti metal, Al metal, and Au metal, and the evaporation rates were 0.5 Å / s, 1.0 Å / s, 0.4 Å / s, and 0.5 Å / s, respectively. This yielded a quantum well LED with an AlGaN / InGaN superlattice well layer. Finally, the substrate 1 was polished and thinned, and then cleaved to obtain a quantum well LED chip with an AlGaN / InGaN superlattice well layer.

[0022] Comparative Example 1

[0023] A method for fabricating InGaN / GaN quantum well LEDs is disclosed. Except for the method of quantum well fabrication, all other fabrication steps are the same as in the previous example. In the multi-quantum well active region, the GaN barrier layer is grown at a temperature of 820 °C and a growth pressure of 400 mbar, with flow rates of TMGa and NH3 of 2.9 μmol / min and 233 mmol / min, respectively, and a thickness of 12 nm. The InGaN potential well layer is grown at a temperature of 720 °C and a growth pressure of 400 mbar, with flow rates of TMIn, TEGa, and NH3 of 6.8 μmol / min, 2.9 μmol / min, and 233 mmol / min, respectively, and a thickness of 2.5 nm. The number of periods in the multi-quantum well is 2.

[0024] like Figure 1 and Figure 2 As shown, the names of each part are: 1 is the substrate, 2 is the nucleation layer, 3 is the undoped GaN layer, 4 is the n-type GaN layer, 5 is the multi-quantum-well active region, 6 is the electron blocking layer, 7 is the p-type GaN layer, 8 is the current spreading layer, 9 is the passivation layer, 10 is the p-type electrode, 10' is the n-type electrode, 11 is the barrier layer GaN, and 12 is the Al in the well superlattice. x Ga 1-x N-layer, 13 is In in the well layer superlattice y Ga 1-y N layers.

[0025] Figure 3 The electroluminescence spectra of the quantum well LED with AlGaN / InGaN superlattice potential well prepared in Example 1 under different driving current densities show that the emission wavelength of the LED changes by only 1.3 nm with the injection current density, which can be considered to be almost unchanged. Figure 4 The relationship between the emission wavelength of quantum well LEDs with AlGaN / InGaN superlattice potential wells and traditional InGaN / GaN quantum well LED chips and the injection current density is shown. It can be seen that the quantum well LEDs with superlattice potential wells have better emission wavelength stability. Figure 3 and Figure 4 The results show that quantum wells with AlGaN / InGaN superlattice potential wells have weaker polarization electric fields.

[0026] Figure 5The normalized external quantum efficiency plots for quantum well LEDs with AlGaN / InGaN superlattice potential wells and conventional InGaN / GaN quantum well LEDs clearly show that the quantum well LED with the superlattice potential well exhibits weaker efficiency decay, approximately one-third that of the conventional InGaN / GaN quantum well LED. This indicates that the polarization-matched superlattice layer and the thinner well layer can effectively reduce the polarization electric field and quantum confinement Stark effect in the LED quantum well, thereby significantly improving the stability of the LED's emission wavelength.

Claims

1. A quantum well LED with an AlGaN / InGaN superlattice well layer, characterized in that: The quantum well LED structure consists of, from bottom to top, a substrate (1), a nucleation layer (2), an undoped GaN layer (3), an n-type GaN layer (4), a multi-quantum well active region (5), an electron blocking layer (6), a p-type GaN layer (7), and a current spreading layer (8). A stepped structure with sidewalls is formed between the n-type GaN layer (4) and the current spreading layer (8). Passivation layers (9) are fabricated on the n-type GaN layer (4), the current spreading layer (8), and the sidewalls. Electrode windows are opened in the passivation layer (9) above the current spreading layer (8) and the n-type GaN layer (4), and p-type electrodes (10) and n-type electrodes (10') are fabricated in the electrode windows, respectively. The multi-quantum well active region (5) is a periodic well / barrier structure with a period number between 2 and 15. The barrier layer (11) is a GaN layer with a thickness of 2 to 15 nm. The well layer is an Al x Ga 1-x N layers (12) and In y Ga 1-y The N-layer (13) periodically alternating superlattice structure has a period number between 1 and 10, where 0 ≤ x < 1 and 0 ≤ y < 1; in each period of the well layer, Al x Ga 1-x The thickness of layer N (12) is a nm, In y Ga 1-y The thickness of layer N (13) is b nm, 0.5≤a≤2, 0.5≤b≤2.

2. A quantum well LED with an AlGaN / InGaN superlattice well layer as described in claim 1, characterized in that: The substrate (1) is a sapphire, carbon-faced or carbon-faced SiC, gallium-faced or nitrogen-faced GaN substrate; the nucleation layer (2) is a GaN or AlN thin film with a thickness of 10~200 nm; the GaN undoped layer (3) is an unintentionally doped GaN layer with a thickness of 200 nm~10 μm; the n-type GaN layer (4) is a Si-doped GaN layer with a doping concentration of 10 18 cm -3 The electron blocking layer (6) is Mg-doped Al, with a thickness of 1~3 μm. m Ga 1-m N-layer, 0.1≤m≤0.3, doping concentration is 10 19 cm -3 The thickness is on the order of magnitude, ranging from 10 to 50 nm; the p-type GaN layer (7) is a Mg-doped GaN layer with a doping concentration of 10. 19 cm -3 The thickness is 100~200 nm; the current spreading layer (8) is indium tin oxide with a thickness of 20~300 nm; the passivation layer (9) is SiO2 with a thickness of 500 nm~2 μm; the p-type electrode (10) and n-type electrode (10') are Ti-Au, Ti-Al-Au, Ti-Al-Ni-Au or Ti-Al-Ti-Au alloy composite materials with a thickness of 60~300 nm.

3. A quantum well LED with an AlGaN / InGaN superlattice well layer as described in claim 1, characterized in that: Nitrogen-polarized LEDs were epitaxially grown on sapphire substrates treated with high-temperature nitriding at ≥900 ℃, and metal-polarized LEDs were epitaxially grown on sapphire substrates treated with low-temperature nitriding at ≤700 ℃; metal-polarized LEDs were epitaxially grown on silicon-faced SiC substrates, and nitrogen-polarized LEDs were epitaxially grown on carbon-faced SiC substrates; metal-polarized LEDs were epitaxially grown on gallium-faced GaN substrates, and nitrogen-polarized LEDs were epitaxially grown on nitrogen-faced GaN substrates.

4. A method for fabricating a quantum well LED with an AlGaN / InGaN superlattice well layer as described in any one of claims 1 to 3, comprising the following steps: 1) A nucleation layer (2), an undoped GaN layer (3), an n-type GaN layer (4), a multi-quantum-well active region (5), an electron blocking layer (6), and a p-type GaN layer (7) are epitaxially grown sequentially on a substrate (1) using metal-organic chemical vapor deposition. Nitrogen is used as the carrier gas when growing the multi-quantum-well active region (5), and hydrogen is used as the carrier gas when growing the remaining parts. TMAl, TMIn, and TMGa are used as Al, In, and Ga sources, respectively. High-purity ammonia is used as the N source. Silane is used as the n-type doping source, and magnesia-dicerocene is used as the p-type doping source. The growth temperature of the nucleation layer (2) is 530~550 ℃, the growth pressure is 100~400 mbar, and the growth thickness is 20~50 nm. The growth temperature of the undoped GaN layer (3) is 1000~1100 ℃, the growth pressure is 100~400 mbar, and the growth thickness is 200 nm~10 nm. μm; the growth temperature of the n-type GaN layer (4) is 1000~1100 ℃, the growth pressure is 100~400 mbar, the growth thickness is 1~3 μm, and the n-type doping concentration is 10 μm. 18 cm -3 In the multi-quantum well active region (5), the growth temperature of the GaN barrier layer (11) is 800~900 ℃, the growth pressure is 100~400 mbar, and the growth thickness is 2~15 nm; the AlGaN / InGaN superlattice well layer is grown by pulse method. In one pulse cycle, ammonia gas is continuously introduced, and TMAl and TMGa are introduced in sequence to grow Al. x Ga 1-x N layers (12), then TMI and TMGa are sequentially introduced to grow In. y Ga 1-y Layer N (13), cycling 1~10 cycles according to this sequence pattern, with a growth temperature of 650~850 ℃ and a growth pressure of 100~400 mbar, Al x Ga 1-x N layers (12) and In y Ga 1-y The thickness of the N layer (13) is 0.5~2 nm, and the number of well / barrier layers in the multi-quantum-well active region (5) is 1~15. x Ga 1-x N layers (12) and In y Ga 1-y The composition of the N-layer (13) can be controlled by adjusting the growth temperature and the amount and time of the source in the pulse growth method; the growth temperature of the electron blocking layer (6) is 900~1000 ℃, the growth pressure is 100~400 mbar, the growth thickness is 10~50 nm, and the p-type doping concentration is 10 19 cm -3 The growth temperature of the p-type GaN layer (7) is 900~1000 ℃, the growth pressure is 100~400 mbar, the growth thickness is 100~200 nm, and the p-type doping concentration is 10 19 cm -3 Magnitude; 2) A transparent indium tin oxide current spreading layer (8) with a thickness of 20~300 nm is prepared on the p-type GaN layer (7) by magnetron sputtering. Then, the current spreading layer (8) is etched down to the n-type GaN layer (4) by inductively coupled plasma etching to obtain the exposed n-type GaN layer (4) mesa. Then, a SiO2 passivation layer (9) with a thickness of 500 nm~2 μm is deposited on the current spreading layer (8), the sidewalls generated by etching, and the exposed n-type GaN layer (4) mesa by plasma-enhanced chemical vapor deposition. Finally, the SiO2 passivation layer (9) is etched by reactive ion etching to form an electrode window, exposing the current spreading layer (8) and the n-type GaN layer (4). Then, p-type electrodes (10) and n-type electrodes (10') with a thickness of 60~300 nm are prepared on the exposed current spreading layer (8) and the exposed n-type GaN layer (4) by thermal evaporation or electron beam evaporation. nm, thereby obtaining the quantum well LED with the AlGaN / InGaN superlattice well layer.

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