Deep ultraviolet LED epitaxial wafer, preparation method and semiconductor device

Abstract

The present invention discloses a deep ultraviolet LED epitaxial wafer, comprising a nitride buffer layer, a nitride transition layer, an n-type nitride layer, a quantum well active layer, an electron blocking layer, and a contact layer sequentially grown on a substrate; wherein the electron blocking layer is a BAlN blocking layer; the quantum well active layer comprises a plurality of alternately grown AlGaN quantum well layers / AlGaN quantum barrier layers, and the last quantum well structure is AlGaN / BAlN. The present invention utilizes a BAIN blocking layer to replace the conventional p-type AlGaN electron blocking layer, which can reduce interface defects with the quantum well and circumvent the p-type doping problem of high Al component AlGaNEBL. At the same time, in order to further improve the wave function overlap rate of the last quantum well, AlGaN / BAlN is used in the last quantum well layer, thereby improving the wave function overlap rate of the last quantum well layer, superimposing the electron-hole wave functions in the quantum well active region, improving the radiation recombination efficiency of the deep ultraviolet LED quantum well region, and thereby improving the power and efficiency of the deep ultraviolet LED.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a deep ultraviolet LED epitaxial wafer, a preparation method and a semiconductor device. Background Art

[0002] Currently, deep-ultraviolet (UV) LEDs (Light-Emitting Diodes) based on AlGaN materials have attracted widespread attention due to their potential applications in disinfection, air and water purification, biochemical testing, and optical communications. However, the low external quantum efficiency of deep-ultraviolet (UV) LEDs still cannot meet current application requirements, mainly due to their low internal quantum efficiency and light extraction efficiency.

[0003] The quantum efficiency of deep-ultraviolet LED chips is relatively low for several reasons: First, the epitaxial quality of the AlGaN material is suboptimal, resulting in a high defect density that leads to low internal quantum efficiency. Furthermore, the electron blocking layer is mostly p-type AlGaN, but AlGaN with a high Al content suffers from p-type doping. When conventional AlGaN electron blocking layers block electrons, the high valence band step hinders the migration of holes to the active region, affecting the internal quantum efficiency. Therefore, a new deep-ultraviolet LED chip is urgently needed to address these issues. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a deep ultraviolet LED epitaxial wafer which improves the droop effect and enhances the luminous efficiency.

[0005] In order to solve the above problems, the present invention provides a deep ultraviolet LED epitaxial wafer, which includes a nitride buffer layer, a nitride transition layer, an n-type nitride layer, a quantum well active layer, an electron blocking layer, and a contact layer grown in sequence on a substrate;

[0006] Among them, the electron blocking layer is a BAlN blocking layer; the quantum well active layer includes multiple alternately grown AlGaN quantum well layers / AlGaN quantum barrier layers, and the last quantum well structure is AlGaN / BAlN; the BAlN blocking layer includes undoped BAlN, and the wave function overlap rate of the last quantum well structure is 35.73%.

[0007] As a further improvement of the present invention, it further comprises a BAlN roughening layer, wherein the BAlN roughening layer is located before the BAlN barrier layer; or, the BAlN roughening layer is a part of the BAlN barrier layer.

[0008] As a further improvement of the present invention, the thickness of the BAlN roughening layer is 2 nm-20 nm.

[0009] As a further improvement of the present invention, when the BAlN roughening layer is located before the BAlN barrier layer, the BAlN roughening layer is grown between the last quantum well structure AlGaN / BAlN and the BAlN barrier layer.

[0010] As a further improvement of the present invention, when the BAlN roughening layer is located before the BAlN barrier layer, the BAlN roughening layer is formed by roughening the BAlN quantum barrier layer in the last quantum well structure AlGaN / BAlN.

[0011] As a further improvement of the present invention, when the BAlN roughened layer is part of the BAlN barrier layer, the BAlN barrier layer includes a first barrier layer and a second barrier layer, the first barrier layer is the BAlN roughened layer, and the second barrier layer is a BAlN non-roughened layer; the thickness of the second barrier layer is greater than that of the first barrier layer, and the first barrier layer is located between the last quantum well structure AlGaN / BAlN and the second barrier layer.

[0012] As a further improvement of the present invention, the BAlN quantum barrier layer in the last quantum well structure AlGaN / BAlN is doped with Si, and the doping concentration of Si is not greater than 1E18 / cm 3 .

[0013] The present invention also provides a method for preparing a deep ultraviolet LED epitaxial wafer, which is used to prepare any of the deep ultraviolet LED epitaxial wafers described above, comprising the following steps:

[0014] S1. growing a nitride buffer layer on a substrate;

[0015] S3, growing a nitride transition layer on the nitride buffer layer;

[0016] S4, growing an n-type nitride layer on the nitride transition layer;

[0017] S5, growing an alternating AlGaN quantum well layer / AlGaN quantum barrier layer on the n-type nitride layer, and growing an AlGaN / BAlN layer as the last quantum well structure to form a quantum well active layer;

[0018] S6, growing a BAlN barrier layer on the last quantum well structure AlGaN / BAlN layer;

[0019] S7. Growing a contact layer on the BAlN barrier layer.

[0020] The present invention also provides a semiconductor device, characterized in that it includes any of the deep ultraviolet LED epitaxial wafers described above.

[0021] Beneficial effects of the present invention:

[0022] The deep ultraviolet LED epitaxial wafer of the present invention utilizes a BAIN barrier layer to replace a conventional p-type AlGaN electron barrier layer, thereby reducing interface defects with the quantum well and avoiding the p-type doping problem of the high Al component AlGaN EBL.

[0023] At the same time, AlGaN / BAlN is used in the last quantum well layer, which improves the wave function overlap rate compared with the existing AlGaN / AlGaN quantum well structure, overcomes the defects caused by the undoped BAlN barrier layer replacing the highly doped traditional AlGaN electron barrier layer, and improves the radiation recombination efficiency of the deep ultraviolet LED quantum well region, thereby improving the power and efficiency of the deep ultraviolet LED.

[0024] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following preferred embodiments are specifically cited and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 1 is a structural diagram of a deep ultraviolet LED epitaxial wafer in Example 1 of the present invention;

[0026] Figure 2 This is the electron leakage concentration diagram of the traditional p-type AlGaN electron blocking layer at different doping concentrations;

[0027] Figure 3 This is a graph of electron leakage concentration of the BAlN barrier layer of the present invention at different doping concentrations;

[0028] Figure 4 This is a graph of the internal quantum efficiency of a traditional p-type AlGaN electron blocking layer at different currents;

[0029] Figure 5 : This is a graph of the internal quantum efficiency of the BAlN barrier layer of the present invention at different currents;

[0030] Figure 6 This is a structural diagram of a deep ultraviolet LED epitaxial wafer in Example 2 of the present invention;

[0031] Figure 7 This is the output power diagram of different structures at different currents;

[0032] Figure 8 It is the wave function overlap ratio when the final quantum well structure adopts AlGaN / AlGaN after BAlN replaces the traditional p-AlGaN;

[0033] Figure 9is the wave function overlap ratio in the first embodiment of the present invention;

[0034] Figure 10 is the wave function overlap ratio in the third embodiment of the present invention;

[0035] Figure 11 It is the wave function overlapping ratio in the fifth embodiment of the present invention.

[0036] Marking Description:

[0037] 10. Substrate; 20. Nitride buffer layer; 30. Nitride transition layer; 40. n-type nitride layer; 50. Quantum well active layer; 51. AlGaN / BAlN; 60. Electron blocking layer; 70. Contact layer; 80. BAlN roughening layer. DETAILED DESCRIPTION

[0038] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0039] Example 1

[0040] like Figure 1 As shown, this embodiment discloses a deep ultraviolet LED epitaxial wafer, which includes a nitride buffer layer 20, a nitride transition layer 30, an n-type nitride layer 40, a quantum well active layer 50, an electron blocking layer 60, and a contact layer 70 grown in sequence on a substrate 10;

[0041] The electron blocking layer 60 is a BAlN blocking layer.

[0042] In the existing technology, the electron blocking layer is mostly P-type AlGaN, but AlGaN with a high Al content has problems such as p-type doping. The existing technology mostly improves the quantum luminescence efficiency by increasing the high doping of AlGaN. Figure 2 , electron leakage concentration of the traditional p-type AlGaN electron blocking layer at different doping concentrations. It can be seen that the higher the Mg doping concentration, the lower the electron leakage concentration. Therefore, it is necessary to increase the Mg doping concentration to improve its electron blocking ability.

[0043] This embodiment uses a BAlN barrier layer, and experimental data show that: Figure 3 Increasing the Mg doping concentration does not increase its ability to block electrons. Therefore, using BAlN as a barrier layer can circumvent the p-type doping problem of high Al content AlGaN EBL.

[0044] Figure 4 is the internal quantum efficiency of the traditional p-type AlGaN electron blocking layer at different currents; Figure 5It is the internal quantum efficiency of the BAlN barrier layer of the present invention at different currents. By comparing the data of the traditional p-type AlGaN electron blocking layer and the BAlN barrier layer of the present invention, it can be seen that for the traditional p-type doped AlGaN. As the Mg doping concentration increases, the internal quantum efficiency gap is large. For BAlN, the increase in the Mg doping concentration has little effect on the change in the internal quantum efficiency. Therefore, undoped or low-doped BAlN can be used as an electron blocking layer, wherein the electron leakage and internal quantum efficiency through low-doped BAlN and undoped BAlN are not much different. Therefore, the BAlN barrier layer is not sensitive to the doping concentration, and the increase in the doping concentration cannot increase the electron blocking ability. The traditional AlGaN electron blocking layer must adopt high Mg doping to obtain high-efficiency deep ultraviolet LEDs.

[0045] The BAlN barrier layer can replace the traditional AlGaN electron barrier layer to suppress electron leakage, probably because the valence band and conduction band of BAlN are 0.2eV lower and 2.1eV higher than those of GaN. Therefore, the interface arrangement between BAlN and AlGaN is conducive to electron conduction and hole injection.

[0046] Furthermore, a comparison of devices fabricated with an undoped BAlN barrier layer and a low-doped BAlN barrier layer revealed that the undoped BAlN barrier layer exhibited higher luminescence intensity in terms of output power. Therefore, the present invention employs an undoped BAlN barrier layer to replace the traditional highly doped AlGaN electron barrier layer. In this embodiment, the quantum well active layer 50 comprises a plurality of alternating AlGaN quantum well layers / AlGaN quantum barrier layers, with the final quantum well layer comprising an AlGaN / BAlN structure 51.

[0047] The traditional deep ultraviolet active layer is a plurality of alternately grown AlGaN quantum well layers / AlGaN quantum barrier layers. The present invention found that after replacing the highly doped traditional AlGaN electron barrier layer with an undoped BAlN barrier layer, the wave function overlap rate of the traditional AlGaN / AlGaN in the last quantum well structure was significantly reduced. Specifically, the last layer is the previous AlGaN / AlGaN quantum well structure, and its wave function overlap rate is between 41% and 42%, while the last layer is the AlGaN / AlGaN quantum well structure, and its wave function overlap rate is 32.99%, which is much lower than the wave function overlap rate of the prior art. Figure 8 .

[0048] Reference Figure 9The present invention further adopts AlGaN / BAlN in the last quantum well structure, and the wave function overlap rate is increased to 35.73%. Compared with the traditional AlGaN / AlGaN quantum well structure, the wave function overlap rate is improved, overcoming the defects caused by replacing the highly doped traditional AlGaN electron blocking layer with an undoped BAlN barrier layer.

[0049] Optionally, the substrate 10 is sapphire; the nitride buffer layer 20 is AlN; the nitride transition layer 30 is AlGaN; the n-type nitride layer 40 is an n-AlGaN layer; and the contact layer 70 is AlN.

[0050] The deep-ultraviolet LED epitaxial wafer in this embodiment utilizes a BAIN barrier layer instead of a conventional p-type AlGaN electron-blocking layer, reducing interface defects with the quantum well and avoiding the p-type doping issues associated with high-Al content AlGaN EBLs. Furthermore, the low-doped or undoped BAIN barrier layer offers excellent electron leakage blocking and hole injection assistance, significantly mitigating the droop effect.

[0051] At the same time, the last quantum well structure adopts AlGaN / BAlN, which improves the wave function overlap rate compared with the traditional AlGaN / AlGaN quantum well structure, overcoming the defects caused by replacing the highly doped traditional AlGaN electron blocking layer with an undoped BAlN barrier layer; improving the radiation recombination efficiency of the deep ultraviolet LED quantum well region, thereby improving the power and efficiency of the deep ultraviolet LED.

[0052] Example 2

[0053] like Figure 6 As shown, this embodiment discloses a deep ultraviolet LED epitaxial wafer, which includes a nitride buffer layer 20, a nitride transition layer 30, an n-type nitride layer 40, a quantum well active layer 50, an electron blocking layer 60, and a contact layer 70 grown in sequence on a substrate 10;

[0054] The electron blocking layer 60 is a BAlN blocking layer; the quantum well active layer 50 includes a plurality of alternately grown AlGaN quantum well layers / AlGaN quantum barrier layers, and the last quantum well structure is AlGaN / BAlN 51 .

[0055] In this embodiment, the deep ultraviolet LED epitaxial wafer further includes a BAlN roughening layer 80. The BAlN roughening layer 80 is located before the BAlN barrier layer and is grown between the last quantum well structure AlGaN / BAlN and the BAlN barrier layer. The thickness of the BAlN roughening layer 80 is preferably 2nm-5nm.

[0056] Alternatively, the BAlN barrier layer comprises undoped BAlN. Replacing p-AlGaN with an undoped BAlN barrier layer can lead to low quantum well wave function overlap. Using AlGaN / BAlN as the final quantum well layer not only reduces dislocations but also, by adding a roughening layer, reduces stress in the quantum well structure and the electron barrier layer, allowing for electron and hole wave function overlap, achieving two goals at once.

[0057] Optionally, the substrate 10 is sapphire; the nitride buffer layer 20 is AlN; the nitride transition layer 30 is AlGaN; the n-type nitride layer 40 is an n-AlGaN layer; and the contact layer 70 is AlN.

[0058] The BAlN roughened layer 80 in this embodiment can increase the effective electron barrier height and reduce electron leakage. Furthermore, after roughening, the BAlN roughened layer 80 can block the lateral expansion of electrons. Furthermore, by first growing the BAlN roughened layer 80 and then growing the undoped BAlN electron blocking layer 60, the surface stress of the BAlN electron blocking layer 60 can be reduced, thereby improving the surface morphology.

[0059] Figure 7 Figure 1 shows the output power of different structures at different currents. Figure a shows a conventional p-type AlGaN electron blocking layer; Figure b shows a low-doped BAlN blocking layer; Figure c shows the undoped BAlN blocking layer in Example 1; and Figure d shows the undoped BAlN blocking layer with a BAlN roughening layer grown on the bottom in Example 2.

[0060] The comparison of output power shows that the undoped BAlN has a higher output power than the doped BAlN. The higher luminous intensity of the undoped BAlN after adding the BAlN roughening layer 80 is due to the BAlN roughening layer 80 storing electrons in the active region, further reducing the problem of electron overflow in the active region.

[0061] Example 3

[0062] This embodiment discloses a deep ultraviolet LED epitaxial wafer, such as Figure 6 As shown, this embodiment discloses a deep ultraviolet LED epitaxial wafer, which includes a nitride buffer layer 20, a nitride transition layer 30, an n-type nitride layer 40, a quantum well active layer 50, an electron blocking layer 60, and a contact layer 70 grown in sequence on a substrate 10;

[0063] The electron blocking layer 60 is a BAlN blocking layer; the quantum well active layer 50 includes a plurality of alternately grown AlGaN quantum well layers / AlGaN quantum barrier layers, and the last quantum well structure is AlGaN / BAlN 51 .

[0064] In this embodiment, the deep ultraviolet LED epitaxial wafer further includes a BAlN roughening layer, which is located before the BAlN barrier layer and is formed by roughening the BAlN quantum barrier layer in the last quantum well structure AlGaN / BAlN. Figure 10 In the third embodiment of the present invention, when BAlN replaces the traditional p-AlGaN, the last quantum well layer in the AlGaN / AlGaN multi-quantum well is AlGaN / BAlN, and the wave function overlap rate after roughening is increased to 39.26%.

[0065] Optionally, the substrate 10 is sapphire; the nitride buffer layer 20 is AlN; the nitride transition layer 30 is AlGaN; the n-type nitride layer 40 is an n-AlGaN layer; and the contact layer 70 is AlN.

[0066] Example 4

[0067] This embodiment discloses a deep ultraviolet LED epitaxial wafer, such as Figure 6 As shown, this embodiment discloses a deep ultraviolet LED epitaxial wafer, which includes a nitride buffer layer 20, a nitride transition layer 30, an n-type nitride layer 40, a quantum well active layer 50, an electron blocking layer 60, and a contact layer 70 grown in sequence on a substrate 10;

[0068] The electron blocking layer 60 is a BAlN blocking layer; the quantum well active layer 50 includes a plurality of alternately grown AlGaN quantum well layers / AlGaN quantum barrier layers, and the last quantum well structure is AlGaN / BAlN 51 .

[0069] In this embodiment, the deep ultraviolet LED epitaxial wafer also includes a BAlN roughening layer, which is part of the BAlN barrier layer. The BAlN barrier layer includes a first barrier layer and a second barrier layer, the first barrier layer being the BAlN roughening layer and the second barrier layer being the BAlN unroughening layer. The second barrier layer is thicker than the first barrier layer, and the first barrier layer is located between the last quantum well structure AlGaN / BAlN layer and the second barrier layer. The thickness of the BAlN roughening layer is preferably 1 / 4 of the BAlN barrier layer, preferably 2nm-20nm.

[0070] Compared to Example 1, this embodiment roughens the lower portion of the original BAlN barrier layer by 1 / 4 of its thickness, forming a BAlN roughened layer. The thickness of the roughened layer is less than that of the unroughened layer. A comparison of output power reveals that roughening the lower portion of the original BAlN barrier layer further increases luminescence intensity. This is because the roughened BAlN layer stores electrons in the active region, further reducing the problem of electron overflow in the active region. Experiments have shown that excessively thick roughened layers can affect the flatness of the epitaxial wafer and reduce its quality. However, when the thickness of the BAlN roughened layer is less than or equal to 1 / 4 of the overall thickness of the BAlN barrier layer, electron overflow in the active region can be further reduced while maintaining epitaxial wafer quality.

[0071] Optionally, the substrate 10 is sapphire; the nitride buffer layer 20 is AlN; the nitride transition layer 30 is AlGaN; the n-type nitride layer 40 is an n-AlGaN layer; and the contact layer 70 is AlN.

[0072] Example 5

[0073] This embodiment discloses a deep ultraviolet LED epitaxial wafer, such as Figure 6 As shown, this embodiment discloses a deep ultraviolet LED epitaxial wafer, which includes a nitride buffer layer 20, a nitride transition layer 30, an n-type nitride layer 40, a quantum well active layer 50, an electron blocking layer 60, and a contact layer 70 grown in sequence on a substrate 10;

[0074] The electron blocking layer 60 is a BAlN blocking layer; the quantum well active layer 50 includes a plurality of alternately grown AlGaN quantum well layers / AlGaN quantum barrier layers, and the last quantum well structure is AlGaN / BAlN 51 .

[0075] In this embodiment, the deep ultraviolet LED epitaxial wafer further includes a BAlN roughening layer, which is located before the BAlN barrier layer and is formed by roughening the BAlN quantum barrier layer in the last quantum well structure AlGaN / BAlN.

[0076] See also Figure 11 When BAlN replaces the traditional p-AlGaN, the last quantum well layer in the AlGaN / AlGaN multi-quantum well is AlGaN / BAlN. After the last BAlN is roughened, its wave function overlap rate is increased to 40.02%, which is equivalent to that in Example 1. This may be because when the roughening layer is located in the BAlN of the last quantum well structure, the stress between the quantum well structure and the electron blocking layer is reduced, causing the electron and hole wave functions to overlap.

[0077] Furthermore, in this embodiment, the BAlN quantum barrier layer can be doped with Si, with the Si doping concentration being no greater than 1E18 / cm3. The wave function overlap ratio after Si doping is 40.99%. This is likely due to the reverse electric field generated by the activated silicon impurities effectively shielding the polarization electric field of the quantum barrier itself, thereby reducing the band tilt in the quantum well active region and increasing the wave function overlap ratio of carriers within the quantum well. This increases the probability of radiative recombination and improves the internal quantum efficiency of the deep ultraviolet LED.

[0078] Among them, in Examples 2, 3, and 4, after BAlN replaces the traditional p-AlGaN, the last quantum well in the AlGaN / AlGaN multiple quantum well is AlGaN / BAlN, which is provided with a roughening layer and is not doped with Si. The wave function overlap rates of the last quantum well of the three embodiments, which are AlGaN / BAlN, are not much different and are all between Example 1 and Example 5.

[0079] It can be seen that when BAlN replaces the traditional p-AlGaN, the wave function overlap ratio is improved when AlGaN / BAlN is used as the final quantum well structure, compared to when the final quantum well structure uses AlGaN / AlGaN. The superposition of electron-hole wave functions in the quantum well active region improves the radiative recombination efficiency in the quantum well region of the deep ultraviolet LED, thereby improving the power and efficiency of the deep ultraviolet LED.

[0080] At the same time, the BAlN quantum barrier layer in the final quantum well AlGaN / BAlN layer has been roughened to further increase the wave function overlap rate, further overcoming the defects caused by replacing the traditional highly doped AlGaN electron barrier layer with an undoped BAlN barrier layer.

[0081] Furthermore, after roughening the BAlN quantum barrier layer in the final quantum well AlGaN / BAlN layer and then doping it with Si, the wave function overlap ratio can be further improved. This is because the reverse electric field generated by the activation of the Si impurities can effectively shield the polarization electric field of the quantum barrier itself, thereby reducing the degree of band tilt in the quantum well active region and increasing the wave function overlap ratio of the carriers within the quantum well. This increases the probability of radiative recombination and achieves an improvement in the quantum efficiency of the deep ultraviolet LED.

[0082] Example 6

[0083] This embodiment discloses a method for preparing a deep ultraviolet LED epitaxial wafer, which is used to prepare the deep ultraviolet LED epitaxial wafer described in Example 1, comprising the following steps:

[0084] S1. growing a nitride buffer layer on a substrate;

[0085] S3, growing a nitride transition layer on the nitride buffer layer;

[0086] S4, growing an n-type nitride layer on the nitride transition layer;

[0087] S5, growing an alternating AlGaN quantum well layer / AlGaN quantum barrier layer on the n-type nitride layer, and growing an AlGaN / BAlN layer as the last quantum well structure to form a quantum well active layer;

[0088] S6, growing a BAlN barrier layer on the last quantum well structure AlGaN / BAlN layer;

[0089] S7. Growing a contact layer on the BAlN barrier layer.

[0090] Example 7

[0091] This embodiment discloses a method for preparing a deep ultraviolet LED epitaxial wafer, which is used to prepare the deep ultraviolet LED epitaxial wafer described in Example 2, comprising the following steps:

[0092] S1. growing a nitride buffer layer on a substrate;

[0093] S3, growing a nitride transition layer on the nitride buffer layer;

[0094] S4, growing an n-type nitride layer on the nitride transition layer;

[0095] S5, growing an alternating AlGaN quantum well layer / AlGaN quantum barrier layer on the n-type nitride layer, and growing an AlGaN / BAlN layer as the last quantum well structure to form a quantum well active layer;

[0096] S6, growing a BAlN roughening layer on the last quantum well structure AlGaN / BAlN layer;

[0097] S7, growing a BAlN barrier layer on the BAlN roughened layer;

[0098] S8. Growing a contact layer on the BAlN barrier layer.

[0099] Example 8

[0100] This embodiment discloses a method for preparing a deep ultraviolet LED epitaxial wafer, which is used to prepare the deep ultraviolet LED epitaxial wafer described in Example 3, comprising the following steps:

[0101] S1. growing a nitride buffer layer on a substrate;

[0102] S3, growing a nitride transition layer on the nitride buffer layer;

[0103] S4, growing an n-type nitride layer on the nitride transition layer;

[0104] S5, growing an alternating AlGaN quantum well layer / AlGaN quantum barrier layer on the n-type nitride layer, and growing an AlGaN / BAlN layer as the last quantum well structure to form a quantum well active layer; and roughening the BAlN quantum barrier layer in the last quantum well AlGaN / BAlN layer;

[0105] S6, growing a BAlN barrier layer on the last quantum well structure AlGaN / BAlN layer;

[0106] S7. Growing a contact layer on the BAlN barrier layer.

[0107] Embodiment 9

[0108] This embodiment discloses a method for preparing a deep ultraviolet LED epitaxial wafer, which is used to prepare the deep ultraviolet LED epitaxial wafer described in Example 4, comprising the following steps:

[0109] S1. growing a nitride buffer layer on a substrate;

[0110] S3, growing a nitride transition layer on the nitride buffer layer;

[0111] S4, growing an n-type nitride layer on the nitride transition layer;

[0112] S5, growing an alternating AlGaN quantum well layer / AlGaN quantum barrier layer on the n-type nitride layer, and growing an AlGaN / BAlN layer as the last quantum well structure to form a quantum well active layer;

[0113] S6, growing the first barrier layer on the last quantum well structure AlGaN / BAlN layer;

[0114] S7, growing the second barrier layer on the first barrier layer;

[0115] S8. Growing the contact layer on the second barrier layer.

[0116] Example 10

[0117] This embodiment discloses a method for preparing a deep ultraviolet LED epitaxial wafer, which is used to prepare the deep ultraviolet LED epitaxial wafer described in Example 5, comprising the following steps:

[0118] S1. growing a nitride buffer layer on a substrate;

[0119] S3, growing a nitride transition layer on the nitride buffer layer;

[0120] S4, growing an n-type nitride layer on the nitride transition layer;

[0121] S5, growing an alternating AlGaN quantum well layer / AlGaN quantum barrier layer on the n-type nitride layer, and growing an AlGaN / BAlN layer as the last quantum well structure to form a quantum well active layer; and roughening the BAlN quantum barrier layer in the last quantum well AlGaN / BAlN layer, and doping the BAlN quantum barrier layer with Si;

[0122] S6, growing a BAlN barrier layer on the last quantum well structure AlGaN / BAlN layer;

[0123] S7. Growing a contact layer on the BAlN barrier layer.

[0124] Example 11

[0125] This embodiment discloses a semiconductor device, which includes the deep ultraviolet LED epitaxial wafer as described in any one of Embodiments 1 to 5.

[0126] The above embodiments are merely preferred embodiments for the purpose of fully illustrating the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

Claims

1. A deep ultraviolet LED epitaxial wafer, characterized in that: It includes a nitride buffer layer, a nitride transition layer, an n-type nitride layer, a quantum well active layer, an electron blocking layer, and a contact layer grown in sequence on a substrate; Among them, the electron blocking layer is a BAlN blocking layer; the quantum well active layer includes multiple alternately grown AlGaN quantum well layers / AlGaN quantum barrier layers, and the last quantum well structure is AlGaN / BAlN; the BAlN blocking layer includes undoped BAlN, and the wave function overlap rate of the last quantum well structure is 35.73%.

2. The deep ultraviolet LED epitaxial wafer according to claim 1, wherein: The method further comprises a BAlN roughening layer, wherein the BAlN roughening layer is located before the BAlN barrier layer; or the BAlN roughening layer is a part of the BAlN barrier layer.

3. The deep ultraviolet LED epitaxial wafer according to claim 2, wherein: The thickness of the BAlN roughened layer is 2 nm to 20 nm.

4. The deep ultraviolet LED epitaxial wafer according to claim 2, wherein: When the BAlN roughening layer is located before the BAlN barrier layer, the BAlN roughening layer is grown between the last quantum well structure AlGaN / BAlN and the BAlN barrier layer.

5. The deep ultraviolet LED epitaxial wafer according to claim 2, wherein: When the BAlN roughening layer is located before the BAlN barrier layer, the BAlN roughening layer is formed by roughening the BAlN quantum barrier layer in the last quantum well structure AlGaN / BAlN.

6. The deep ultraviolet LED epitaxial wafer according to claim 2, wherein: When the BAlN roughened layer is part of the BAlN barrier layer, the BAlN barrier layer includes a first barrier layer and a second barrier layer, the first barrier layer is the BAlN roughened layer, and the second barrier layer is a BAlN non-roughened layer; the thickness of the second barrier layer is greater than that of the first barrier layer, and the first barrier layer is located between the last quantum well structure AlGaN / BAlN and the second barrier layer.

7. The deep ultraviolet LED epitaxial wafer according to claim 1, wherein: The BAlN quantum barrier layer in the last quantum well structure AlGaN / BAlN is doped with Si, and the doping concentration of Si is not greater than 1E18 / cm 3 .

8. A method for preparing a deep ultraviolet LED epitaxial wafer, characterized in that: The method for preparing a deep ultraviolet LED epitaxial wafer according to any one of claims 1 to 7 comprises the following steps: S1. growing a nitride buffer layer on a substrate; S3, growing a nitride transition layer on the nitride buffer layer; S4, growing an n-type nitride layer on the nitride transition layer; S5, growing an alternating AlGaN quantum well layer / AlGaN quantum barrier layer on the n-type nitride layer, and growing an AlGaN / BAlN layer as the last quantum well structure to form a quantum well active layer; S6, growing a BAlN barrier layer on the last quantum well structure AlGaN / BAlN layer; S7. Growing a contact layer on the BAlN barrier layer.

9. A semiconductor device, characterized in that It comprises the deep ultraviolet LED epitaxial wafer as described in any one of claims 1-7.

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