An AlGaN-based deep ultraviolet light-emitting diode chip and a preparation method thereof

Abstract

The present invention provides an AlGaN-based deep ultraviolet light-emitting diode chip and a preparation method thereof. The chip sequentially includes: a sapphire substrate, an AlN buffer layer, an undoped AlGaN layer, an N-type doped AlGaN layer, a multiple quantum well layer, an electron blocking layer, a P-type doped GaN layer, and a contact layer; wherein, the multiple quantum well layer includes multiple periods of quantum well structures, and a single period of quantum well structure includes an AlxGa1-xN layer and an AlyGa1-yN barrier layer, where x and y are constants greater than 0, and an InGaN layer is provided between the AlxGa1-xN layer and the AlyGa1-yN barrier layer to regulate the strain state of AlGaN in a single period of quantum well structure through the InGaN layer. The present invention can solve the problem in the prior art that only the light extraction problem caused by internal total reflection can be improved, and the problem of lateral propagation of the light emitted from the deep ultraviolet LED quantum well light-emitting region cannot be fundamentally solved.

Description

Technical Field

[0001] The present invention relates to the field of chip technology, and particularly relates to an AlGaN-based deep ultraviolet light-emitting diode chip and a preparation method thereof. Background Art

[0002] In the past decade, AlGaN materials have attracted much attention due to their great application potential in ultraviolet optoelectronic devices. Ultraviolet LEDs have the characteristics of high photon energy, short wavelength, small volume, low power consumption, long life, and environmental friendliness, and have wide applications in fields such as high color rendering index white light illumination, high-density optical data storage, sensors, lithography, and air purification and environmental protection.

[0003] For AlGaN-based LEDs, their luminous efficiency is usually determined by three efficiencies: internal quantum efficiency, carrier input efficiency, and light extraction efficiency. At present, the main factors affecting AlGaN-based LEDs are the difficulty in epitaxial growth of high-Al-component AlGaN materials, the difficulty in p-type doping, and the unique optical polarization characteristics.

[0004] At present, the internal quantum efficiency of AlGaN-based ultraviolet LEDs is much lower than that of blue-green light-emitting diodes. As the Al component of AlGaN-based ultraviolet LEDs increases, due to the unique optical anisotropy of AlGaN materials, it is difficult to effectively extract the ultraviolet light emitted in the active region from the surface of the device grown along the c-axis direction conventionally. In addition, since the luminescence of the material mainly depends on the electron transition from the bottom of the conduction band to the vicinity of the top of the valence band in the energy band, the energy level transition is closely related to the dielectric constant. When the Al component increases, the luminescence polarization state at the band edge changes from the TE mode propagating in the forward direction to the TM mode propagating laterally, which severely restricts the emission of deep ultraviolet light.

[0005] In the prior art, the research on improving the light extraction efficiency of AlGaN-based ultraviolet LEDs mainly focuses on fabricating distributed Bragg reflectors at the bottom of the substrate, preparing periodic arrays of photonic crystals on the surface of the epitaxial layer, inserting metal nanodots in the epitaxial layer, and using surface plasmon polaritons to regulate the emitted light field. However, these methods can only improve the light extraction problem caused by total internal reflection and cannot fundamentally solve the problem of lateral propagation of the emitted light from the quantum well luminescence region of deep ultraviolet LEDs. Summary of the Invention

[0006] Based on this, the purpose of the present invention is to provide an AlGaN-based deep ultraviolet light-emitting diode chip and a preparation method thereof, aiming to solve the technical problems recorded in the background art.

[0007] One aspect of the present invention provides an AlGaN-based deep ultraviolet light-emitting diode chip, which sequentially includes: a sapphire substrate, an AlN buffer layer disposed on the sapphire substrate, an undoped AlGaN layer disposed on the AlN buffer layer, an N-type doped AlGaN layer disposed on the undoped AlGaN layer, a multi-quantum well layer disposed on the N-type doped AlGaN layer, an electron blocking layer disposed on the multi-quantum well layer, a P-type doped GaN layer disposed on the electron blocking layer, and a contact layer disposed on the P-type doped GaN layer;

[0008] Wherein, the multi-quantum well layer includes a plurality of periods of quantum well structures, and a single period of the quantum well structure includes an AlxGa1-xN well layer and an AlyGa1-yN barrier layer. Wherein, x and y are constants greater than 0, and an InGaN layer is disposed between the AlxGa1-xN well layer and the AlyGa1-yN barrier layer to regulate the strain state of AlGaN in a single period of the quantum well structure through the InGaN layer.

[0009] According to one aspect of the above technical solution, the multi-quantum well layer includes 5-12 periods of quantum well structures. In each period of the quantum well structure, the AlxGa1-xN well layer is the well layer, the AlyGa1-yN barrier layer is the barrier layer, and the InGaN layer is the thin insertion layer.

[0010] According to one aspect of the above technical solution, the thickness of the AlxGa1-xN well layer in a single period of the multi-quantum well layer is 3nm - 5nm, the growth temperature is 1000°C - 1100°C, the growth pressure is 40Torr - 80Torr, where 0 < x < 0.2.

[0011] According to one aspect of the above technical solution, x in the AlxGa1-xN well layer is 0.1.

[0012] According to one aspect of the above technical solution, the thickness of the AlyGa1-yN barrier layer in a single period of the multi-quantum well layer is between 10nm and 20nm, the growth temperature is 1000°C - 1200°C, the growth pressure is 40Torr - 60Torr, where 0.4 < y < 0.8.

[0013] According to one aspect of the above technical solution, y in the AlyGa1-yN barrier layer is 0.6.

[0014] According to one aspect of the above technical solution, the thickness of the InGaN layer in a single period of the multi-quantum well layer is 1nm - 2nm, the growth temperature is 1000°C - 1100°C, the growth pressure is 50Torr - 100Torr, where the In composition is between 0 and 0.1.

[0015] Another aspect of the present invention is to provide a method for fabricating an AlGaN-based deep ultraviolet light-emitting diode chip for fabricating the AlGaN-based deep ultraviolet light-emitting diode chip described in the above technical solution. The fabrication method includes:

[0016] Providing a sapphire substrate;

[0017] Growing an AlN buffer layer on the sapphire substrate;

[0018] Growing an undoped AlGaN layer on the AlN buffer layer;

[0019] Growing an N-type doped AlGaN layer on the undoped AlGaN layer;

[0020] Growing a multi-quantum well layer on the N-type doped AlGaN layer;

[0021] Growing an electron blocking layer on the multi-quantum well layer;

[0022] Growing a P-type doped GaN layer on the electron blocking layer;

[0023] And growing a contact layer on the P-type doped GaN layer;

[0024] Wherein, the multi-quantum well layer includes multiple periods of quantum well structures. A single period of the quantum well structure includes an AlxGa1-xN layer and an AlyGa1-yN barrier layer. Wherein, x and y are constants greater than 0, and an InGaN layer is provided between the AlxGa1-xN layer and the AlyGa1-yN barrier layer to regulate the strain state of AlGaN in a single period of the quantum well structure through the InGaN layer.

[0025] According to one aspect of the above technical solution, the step of growing a multi-quantum well layer on the N-type doped AlGaN layer specifically includes:

[0026] Growing a first period of quantum well structure on the N-type doped AlGaN layer. The first period of the quantum well structure includes an AlxGa1-xN layer and an AlyGa1-yN barrier layer, and an InGaNInGaN layer is inserted between the AlxGa1-xN layer and the AlyGa1-yN barrier layer;

[0027] Growing an AlxGa1-xN layer, an InGaN layer, and an AlyGa1-yN barrier layer in sequence on the previous period as the quantum well structure of the next period until a preset 5-12 periods are reached.

[0028] According to one aspect of the above technical solution, in the step of growing a multi-quantum well layer on the N-type doped AlGaN layer:

[0029] The thickness of the AlxGa1-xN well layer within a single period of the multiple quantum well layer is 3 nm - 5 nm, the growth temperature is 1000 °C - 1100 °C, and the pressure range is 40 Torr - 80 Torr, where 0 < x < 0.2;

[0030] The thickness of the AlyGa1-yN barrier layer within a single period of the multiple quantum well layer is 10 nm - 20 nm, the growth temperature is 1000 °C - 1200 °C, and the growth pressure is 40 Torr - 60 Torr, where 0.4 < y < 0.8;

[0031] The thickness of the InGaN layer within a single period of the multiple quantum well layer is 1 nm - 2 nm, the growth temperature is 1000 °C - 1100 °C, and the growth pressure is between 50 Torr - 100 Torr, where the In composition is between 0 - 0.1.

[0032] Compared with the prior art, the AlGaN-based deep ultraviolet light-emitting diode chip and its manufacturing method described in this embodiment have the beneficial effects that: by inserting an InGaN layer between the AlxGa1-xN well layer and the AlyGa1-yN barrier layer within the quantum well structure of a single period in the multiple quantum well layer, a tensile stress can be applied to the quantum well structure, converting the strain of AlGaN in the quantum well structure into a compressive stress state. Furthermore, the crystal field splitting band gradually moves towards the low-energy direction, while the heavy / light hole bands move towards the high-energy direction, resulting in the dominant light polarization characteristic of the band-edge transition changing from the TM mode of lateral propagation to the TE mode propagating along the c-axis growth direction, thus being beneficial to improving the front light extraction efficiency of the deep ultraviolet LED. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic structural diagram of the AlGaN-based deep ultraviolet light-emitting diode chip in the first embodiment of the present invention;

[0034] Figure 2 It is a schematic structural diagram of the multiple quantum well layer in the first embodiment of the present invention;

[0035] Figure 3 It is a schematic flow diagram of the manufacturing method of the AlGaN-based deep ultraviolet light-emitting diode chip in the second embodiment of the present invention;

[0036] Description of the reference numerals:

[0037] Sapphire substrate 10, AlN buffer layer 20, undoped AlGaN layer 30, N-type doped AlGaN layer 40, multiple quantum well layer 50, quantum well structure 51, AlxGa1-xN layer 510, AlyGa1-yN barrier layer 511, InGaN layer 512, electron blocking layer 60, P-type doped GaN layer 70, contact layer 80;

[0038] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. Specific embodiments

[0039] For the convenience of understanding the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present invention more thorough and comprehensive.

[0040] Embodiment 1

[0041] Please refer to Figure 1-2 , the first embodiment of the present invention provides an AlGaN-based deep ultraviolet light-emitting diode chip, which sequentially includes: a sapphire substrate 10, an AlN buffer layer 20 provided on the sapphire substrate 10, an undoped AlGaN layer 30 provided on the AlN buffer layer 20, an N-type doped AlGaN layer 40 provided on the undoped AlGaN layer 30, a multiple quantum well layer 50 provided on the N-type doped AlGaN layer 40, an electron blocking layer 60 provided on the multiple quantum well layer 50, a P-type doped GaN layer 70 provided on the electron blocking layer 60, and a contact layer 80 provided on the P-type doped GaN layer 70;

[0042] By way of example and not limitation, as Figure 2 shown, the multiple quantum well layer 50 includes 8 periods of quantum well structures 51. A single period of the quantum well structure 51 includes an AlxGa1-xN layer 510 and an AlyGa1-yN barrier layer 511, where x and y are constants greater than 0; and an InGaN layer 512 is inserted between the AlxGa1-xN layer 510 and the AlyGa1-yN barrier layer 511. In this quantum well structure 51, the AlxGa1-xN layer 510 is the well layer, the AlyGa1-yN barrier layer 511 is the barrier layer, and the InGaN layer 512 is the thin insertion layer.

[0043] By inserting a thin InGaN layer 512 between the AlxGa1-xN layer 510 and the AlyGa1-yN barrier layer 511, the strain state of AlGaN in the quantum well structure 51 within a single period is regulated through the InGaN layer 512. In some other embodiments, the multiple quantum well layer 50 may be a quantum well structure 51 with 5 - 12 periods.

[0044] Among them, the growth conditions of the AlxGa1-xN well layer within the quantum well structure 51 of a single period in the multiple quantum well layer 50 are: the growth temperature is 1000°C - 1100°C, and the growth pressure is 40 Torr - 80 Torr; where Torr is Torr, a pressure unit, 1 Torr is 1 mmHg, or 760 Torr = 1 atm (standard atmospheric pressure). The AlxGa1-xN well layer within each period of the quantum well structure 51 is grown according to the above growth conditions. In some feasible embodiments, the thickness of the grown AlxGa1-xN well layer is 3 nm - 5 nm.

[0045] Furthermore, the growth conditions of the AlyGa1-yN barrier layer 511 within the quantum well structure 51 of a single period in the multiple quantum well layer 50 are: the growth temperature is 1000°C - 1200°C, and the growth pressure is 40 Torr - 60 Torr; the AlyGa1-yN barrier layer 511 within each period of the quantum well structure 51 is grown according to the above growth conditions. In some feasible embodiments, the thickness of the grown AlyGa1-yN barrier layer 511 is 10 nm - 20 nm.

[0046] Specifically, both x and y in the AlxGa1-xN layer 510 and the AlyGa1-yN barrier layer 511 are arbitrary constants greater than 0. By way of example and not limitation, a single period of the quantum well structure 51 includes, for example, an Al 0.1 Ga1- 0.1 N layer and an Al 0.6 Ga1- 0.6 N layer, and an InGaN layer 512 disposed between the Al 0.1 Ga1- 0.1 N layer and the Al 0.6 Ga1- 0.6 N layer.

[0047] In this embodiment, the growth conditions of the InGaN layer 512 for regulating the strain state of AlGaN in the quantum well structure 51 of a single period are: the growth temperature is 1000°C - 1100°C, the growth pressure is 50 Torr - 100 Torr, where the In composition is between 0 and 0.1; the InGaN layer 512 within each period of the quantum well structure 51 is grown according to the above growth conditions. In some feasible embodiments, the thickness of the InGaN layer 512 is 1 nm - 2 nm.

[0048] Please refer to Table 1. Table 1 is a comparison table of the luminescence data of the multi-quantum well structure 51 using the traditional structure and the structure of this solution:

[0049] Table 1

[0050]

[0051] According to Table 1, when the emission wavelength, forward voltage, and reverse voltage are all equal, by adopting the structure of the multi-quantum well layer 50 shown in this embodiment, the electroluminescence intensity (EL intensity) is increased by about 12%, and the optical output power (Output power) is increased by about 9.8%.

[0052] In summary, by inserting an InGaN layer between the AlxGa1-xN well layer and the AlyGa1-yN barrier layer in the quantum well structure of a single period in the multi-quantum well layer, a tensile stress can be applied to the quantum well structure, converting the strain of AlGaN in the quantum well structure into a compressive stress state. As a result, its crystal field splitting band gradually moves towards the low-energy direction, while the heavy / light hole bands move towards the high-energy direction, causing the light polarization characteristic of its band-edge transition to change from the laterally propagating TM mode to the TE mode dominated by the propagation along the c-axis growth direction, which is beneficial to improving the front light extraction efficiency of deep ultraviolet LEDs.

[0053] Embodiment 2

[0054] Please refer to Figure 3 , the second embodiment of the present invention provides a method for manufacturing an AlGaN-based deep ultraviolet light emitting diode chip for manufacturing the AlGaN-based deep ultraviolet light emitting diode chip in the above first embodiment. The manufacturing method includes steps S10 - S80, where:

[0055] Step S10, providing a sapphire substrate.

[0056] Step S20, growing an AlN buffer layer on the sapphire substrate.

[0057] Step S30, growing an undoped AlGaN layer on the AlN buffer layer.

[0058] Step S40, growing an N-type doped AlGaN layer on the undoped AlGaN layer.

[0059] Step S50, growing a multi-quantum well layer on the N-type doped AlGaN layer.

[0060] Specifically, a first-period quantum well structure is grown on the N-type doped AlGaN layer. The first-period quantum well structure includes an AlxGa1-xN layer and an AlyGa1-yN barrier layer, and an InGaN layer is inserted between the AlxGa1-xN layer and the AlyGa1-yN barrier layer;

[0061] On the previous period, an AlxGa1-xN layer, an InGaN layer, and an AlyGa1-yN barrier layer are sequentially grown as the quantum well structure of the next period until a preset number of 5-12 periods is reached. The quantum well structure of a single period includes an AlxGa1-xN layer and an AlyGa1-yN barrier layer, where x and y are constants greater than 0, and an InGaN layer is provided between the AlxGa1-xN layer and the AlyGa1-yN barrier layer to regulate the strain state of AlGaN in the quantum well structure of a single period through the InGaN layer.

[0062] Among them, the thickness of the AlxGa1-xN well layer in a single period of the multiple quantum well layer is 3 nm - 5 nm, the growth temperature is 1000 °C - 1100 °C, and the pressure range is 40 Torr - 80 Torr, where 0 < x < 0.2;

[0063] The thickness of the AlyGa1-yN barrier layer in a single period of the multiple quantum well layer is 10 nm - 20 nm, the growth temperature is 1000 °C - 1200 °C, and the growth pressure is 40 Torr - 60 Torr, where 0.4 < y < 0.8;

[0064] The thickness of the InGaN layer in a single period of the multiple quantum well layer is 1 nm - 2 nm, the growth temperature is 1000 °C - 1100 °C, and the growth pressure is between 50 Torr - 100 Torr, where the In composition is between 0 - 0.1.

[0065] Step S60, grow an electron blocking layer on the multiple quantum well layer.

[0066] Step S70, grow a P-type doped GaN layer on the electron blocking layer.

[0067] Step S80, and grow a contact layer on the P-type doped GaN layer.

[0068] In this embodiment, the detailed steps of the preparation method include:

[0069] Provide a substrate, which mostly uses sapphire Al2O3 with the (0001) crystal orientation as the substrate;

[0070] An AlN buffer layer is grown on a substrate by physical vapor deposition; the growth conditions of the AlN buffer layer are: the growth temperature is 400 - 650 °C, the sputtering power is 2000 - 4000 W, and the pressure is 1 - 10 torr; the thickness of the AlN buffer layer is 15 nm - 50 nm;

[0071] The AlN buffer layer is subjected to in-situ annealing treatment in a hydrogen atmosphere of metal-organic chemical vapor deposition, the temperature is 1000 °C - 1200 °C, the pressure range is 150 Torr - 500 Torr, and the time is 5 min - 10 min;

[0072] After the annealing of the AlN buffer layer is completed, the temperature is adjusted to 1050 °C - 1200 °C, and an undoped AlGaN layer with a thickness of 1.0 μm - 3.0 μm is grown, the growth pressure is 50 Torr - 100 Torr, and the Al component is 0.3 - 0.8;

[0073] After the growth of the undoped AlGaN layer is completed, a Si-doped N-type AlGaN layer is grown, with a thickness of 1.0 μm - 3.0 μm, the growth temperature is 1100 °C - 1200 °C, and the growth pressure is 50 Torr - 100 Torr; among them, the Si doping concentration is 1019 cm -3 -1020 cm -3 , and the Al component is 0.2 - 0.6;

[0074] After the growth of the N-type doped AlGaN layer is completed, a multi-quantum well layer is grown. The multi-quantum well layer includes 5 to 12 periods of AlxGa1-xN / InGaN / AlyGa1-yN. Among them, AlxGa1-xN is the well layer, AlyGa1-yN is the barrier layer, and InGaN is the thin insertion layer; the thickness of the AlxGa1-xN well layer in a single period of the multi-quantum well layer is 3 nm - 5 nm, the growth temperature is 1000 °C - 1100 °C, the growth pressure is between 40 Torr and 80 Torr, and 0 < x < 0.2; the thickness of the AlyGa1-yN barrier layer in a single period is 10 nm - 20 nm, the growth temperature is 1000 °C - 1200 °C, the growth pressure is 40 Torr - 60 Torr, and 0.4 < y < 0.8; the thickness of the InGaN layer in a single period is 1 nm - 2 nm, the growth temperature is 1000 °C - 1100 °C, the growth pressure is 50 Torr - 100 Torr, and the In component is 0 - 0.1;

[0075] After the growth of the multi-quantum well layer is completed, an AlGaN electron blocking layer is grown on the multi-quantum well layer, the growth temperature is 1000 °C - 1100 °C, the growth pressure is 50 Torr - 100 Torr, the thickness is 20 nm - 100 nm, and the Al component is 0.1 - 0.5;

[0076] After the growth of the multi-quantum well layer is completed, a Mg-doped P-type GaN layer is grown on the electron blocking layer, with a thickness of 30 nm - 200 nm, a growth temperature of 950 °C - 1050 °C, a growth pressure of 50 Torr - 300 Torr, and a Mg doping concentration of 1019 cm -3 - 1020 cm -3 ;

[0077] After the growth of the P-type GaN layer is completed, an AlGaN contact layer is grown on the P-type GaN layer, with a thickness of 10 nm - 50 nm, a growth temperature of 1000 °C - 1100 °C, a growth pressure of 50 Torr - 100 Torr, and an Al component of 0.0 - 0.3;

[0078] After the growth of the above epitaxial structure is completed, the temperature of the reaction chamber is reduced, and annealing treatment is carried out in a nitrogen atmosphere. The annealing temperature is 650 °C - 850 °C, and the annealing time is 5 min - 15 min until the epitaxial growth at room temperature is completed.

[0079] Among them, trimethylaluminum (TMAl), trimethylgallium or triethylgallium (TMGa or TEGa), and NH3 are used as the precursors of group III sources and group V sources respectively, silane and bis(cyclopentadienyl)magnesium are used as the precursors of N-type dopants and P-type dopants respectively, and N2 and H2 are used as carrier gases.

[0080] In summary, when preparing an AlGaN-based deep ultraviolet light-emitting diode chip, by inserting an InGaN layer between the AlxGa1 - xN well layer and the AlyGa1 - yN barrier layer in the quantum well structure of a single period in the multi-quantum well layer, a tensile stress can be applied to the quantum well structure, converting the strain of AlGaN in the quantum well structure into a compressive stress state. Then, the crystal field splitting band gradually moves towards the low-energy direction, while the heavy / light hole bands move towards the high-energy direction, resulting in the dominant light polarization characteristic of the band-edge transition changing from the TM mode of lateral propagation to the TE mode of propagation along the c-axis growth direction, which is beneficial to improving the forward light extraction efficiency of the deep ultraviolet LED.

[0081] In the description of this specification, the description referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0082] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation to the scope of the patent for the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention shall be subject to the appended claims.

Claims

1. An AlGaN-based deep ultraviolet light-emitting diode chip, characterized in that, The chip sequentially includes: a sapphire substrate, an AlN buffer layer disposed on the sapphire substrate, an undoped AlGaN layer disposed on the AlN buffer layer, an N-type doped AlGaN layer disposed on the undoped AlGaN layer, a multi-quantum well layer disposed on the N-type doped AlGaN layer, an electron blocking layer disposed on the multi-quantum well layer, a P-type doped GaN layer disposed on the electron blocking layer, and a contact layer disposed on the P-type doped GaN layer; Wherein, the multi-quantum well layer includes 5-12 periods of quantum well structures. A single period of the quantum well structure includes an AlxGa1-xN well layer and an AlyGa1-yN barrier layer. Wherein, x and y are constants greater than 0, and an InGaN layer is disposed between the AlxGa1-xN well layer and the AlyGa1-yN barrier layer. The InGaN layer is a thin insertion layer to regulate the strain state of AlGaN in a single period of the quantum well structure through the InGaN layer, change the light polarization characteristics of the deep ultraviolet light-emitting diode chip, and turn the lateral TM mode to the forward TE mode.

2. The AlGaN-based deep ultraviolet light-emitting diode chip according to claim 1, wherein The thickness of the AlxGa1-xN well layer in a single period of the multi-quantum well layer is 3nm-5nm, the growth temperature is 1000℃-1100℃, the growth pressure is 40Torr-80Torr, where 0<x<0.

2.

3. The AlGaN-based deep ultraviolet light-emitting diode chip according to claim 2, characterized in that, x in the AlxGa1-xN well layer is 0.

1.

4. The AlGaN-based deep ultraviolet light-emitting diode chip according to claim 1, characterized in that, The thickness of the AlyGa1-yN barrier layer in a single period of the multi-quantum well layer is between 10nm-20nm, the growth temperature is 1000℃-1200℃, the growth pressure is 40Torr-60Torr, where 0.4<y<0.

8.

5. The AlGaN-based deep ultraviolet light-emitting diode chip according to claim 4, wherein y in the AlyGa1-yN barrier layer is 0.

6.

6. The AlGaN-based deep ultraviolet light-emitting diode chip according to claim 1, characterized in that, The thickness of the InGaN layer in a single period of the multi-quantum well layer is 1nm-2nm, the growth temperature is 1000℃-1100℃, the growth pressure is 50Torr-100Torr, where the In composition is between 0-0.

1.

7. A method for preparing an AlGaN-based deep ultraviolet light-emitting diode chip, characterized in that, For preparing the AlGaN-based deep ultraviolet light-emitting diode chip according to any one of claims 1-6, the preparation method includes: Providing a sapphire substrate; Growing an AlN buffer layer on the sapphire substrate; Growing an undoped AlGaN layer on the AlN buffer layer; Growing an N-type doped AlGaN layer on the undoped AlGaN layer; Growing a multi-quantum well layer on the N-type doped AlGaN layer; Growing an electron blocking layer on the multi-quantum well layer; Growing a P-type doped GaN layer on the electron blocking layer; And growing a contact layer on the P-type doped GaN layer; Among them, the multiple quantum well layer includes multiple periods of quantum well structures. A single period of the quantum well structure includes an AlxGa1-xN layer and an AlyGa1-yN barrier layer. Here, x and y are constants greater than 0, and an InGaN layer is provided between the AlxGa1-xN layer and the AlyGa1-yN barrier layer to regulate the strain state of AlGaN in a single period of the quantum well structure through the InGaN layer.

8. The preparation method of the AlGaN-based deep ultraviolet light-emitting diode chip according to claim 7, characterized in that, The step of growing a multiple quantum well layer on the N-type doped AlGaN layer specifically includes: Growing a first period of quantum well structure on the N-type doped AlGaN layer. This first period of quantum well structure includes an AlxGa1-xN layer and an AlyGa1-yN barrier layer, and inserting an InGaN layer between the AlxGa1-xN layer and the AlyGa1-yN barrier layer; Sequentially growing an AlxGa1-xN layer, an InGaN layer, and an AlyGa1-yN barrier layer on the previous period as the quantum well structure of the next period until reaching a preset 5 - 12 periods.

9. The preparation method of the AlGaN-based deep ultraviolet light-emitting diode chip according to claim 7, characterized in that, In the step of growing a multiple quantum well layer on the N-type doped AlGaN layer: The thickness of the AlxGa1-xN well layer in a single period of the multiple quantum well layer is 3nm - 5nm, the growth temperature is 1000℃ - 1100℃, and the pressure range is 40Torr - 80Torr, where 0 < x < 0.2; The thickness of the AlyGa1-yN barrier layer in a single period of the multiple quantum well layer is 10nm - 20nm, the growth temperature is 1000℃ - 1200℃, and the growth pressure is 40Torr - 60Torr, where 0.4 < y < 0.8; The thickness of the InGaN layer in a single period of the multiple quantum well layer is 1nm - 2nm, the growth temperature is 1000℃ - 1100℃, and the growth pressure is between 50Torr - 100Torr, where the In composition is between 0 - 0.1.

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