Highly hydrolysis-resistant LED epitaxial wafer and preparation method thereof

Abstract

The application relates to the technical field of light emitting diodes, and discloses a high-hydrolysis-resistant LED epitaxial wafer and a preparation method thereof. The high-hydrolysis-resistant LED epitaxial wafer comprises a substrate, and a buffer layer, a U-shaped GaN layer, an N-type semiconductor layer, a superlattice layer, a multi-quantum well layer, an electron blocking layer and a P-type semiconductor layer are sequentially arranged on the substrate; wherein the N-type semiconductor layer is a periodic structure formed by cyclically and alternately growing a GaN layer and a Si-doped AlGaN layer; and the superlattice layer comprises periodically and alternately stacked Si-doped GaN layers and InGaN layers. By implementing the application, the hydrolysis resistance and the light emitting efficiency of a blue-green LED epitaxial wafer can be effectively improved, and the process is simple, and no additional chip process is needed.

Description

Technical Field

[0001] This invention relates to the technical field of light-emitting diodes, and more particularly to a highly hydrolysis-resistant LED epitaxial wafer and its preparation method. Background Technology

[0002] GaN-based LED blue-green epitaxial wafers are key materials widely used in optoelectronic devices. Their epitaxial structures typically include an N-type GaN layer, a quantum well layer, and a P-type GaN layer. In existing technologies, the N-type GaN layer usually employs a Si-doped GaNBULK structure or a cyclic structure of an undoped GaN layer and a Si-doped GaN layer. By doping with Si, the N-type GaN layer exhibits N-polarity, resulting in high electrical and optical performance in LED chip manufacturing. However, this type of LED chip epitaxial structure has poor resistance to hydrolysis. During chip dicing, the dicing path exposes the N-type GaN layer, which is highly susceptible to hydrolysis at high temperatures. This hydrolysis process leads to corrosion of the N-type GaN layer, reduced chip brightness, and in severe cases, electrode detachment, thus affecting the overall performance and lifespan of the LED chip.

[0003] Currently, a common method to improve this situation is to add a deep etching process during chip manufacturing. Deep etching can effectively remove areas that may cause hydrolysis, thereby improving the chip's resistance to hydrolysis. However, deep etching also increases production costs and prolongs process time, negatively impacting the manufacturing efficiency and economic benefits of LED chips. Therefore, for GaN-based LED blue-green epitaxial wafers, adjusting and optimizing their epitaxial structure has become a key research direction for improving their hydrolysis resistance. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a highly hydrolysis-resistant LED epitaxial wafer and its preparation method, which can effectively improve the hydrolysis resistance and luminous efficiency of blue-green LED epitaxial wafers, and the process is simple and does not require additional chip processing.

[0005] To solve the above-mentioned technical problems, the first aspect of the present invention provides a highly hydrolysis-resistant LED epitaxial wafer, comprising a substrate, wherein a buffer layer, a U-type GaN layer, an N-type semiconductor layer, a superlattice layer, a multiple quantum well layer, an electron blocking layer and a P-type semiconductor layer are sequentially disposed on the substrate.

[0006] The N-type semiconductor layer is a periodic structure formed by the alternating growth of GaN and Si-doped AlGaN layers;

[0007] The superlattice layer comprises periodically alternating layers of Si-doped GaN and InGaN.

[0008] As an improvement to the above scheme, the number of cycles of the N-type semiconductor layer is 40-50, and the total thickness of the N-type semiconductor layer is 1.4μm-1.6μm.

[0009] As an improvement to the above scheme, in a single cycle, the thickness of the GaN layer is 15nm-20nm, and the thickness of the Si-doped AlGaN layer is 15nm-20nm.

[0010] As an improvement to the above scheme, in the N-type semiconductor, the Si doping concentration in the Si-doped AlGaN layer is 1×10⁻⁶. 19 atoms / cm 3 -2×10 19 atoms / cm 3 The Al component accounts for 0.1-0.2%.

[0011] As an improvement to the above scheme, the number of periods in the superlattice layer is 3-6, and the total thickness of the superlattice layer is [missing information].

[0012] In a single cycle, the thickness ratio of the Si-doped GaN layer to the InGaN layer is (4-10):1.

[0013] As an improvement to the above scheme, the Si doping concentration in the Si-doped GaN layer is lower than the Si doping concentration in the Si-doped AlGaN layer.

[0014] As an improvement to the above scheme, the Si doping concentration in the Si-doped GaN layer is 4 × 10⁻⁶. 18 atoms / cm 3 -5×10 18 atoms / cm 3 ;

[0015] The InGaN layer contains 0.1-0.2% In content.

[0016] As an improvement to the above scheme, the growth temperature of the GaN layer and the Si-doped AlGaN layer is higher than that of the Si-doped GaN layer and the InGaN layer.

[0017] The growth pressure of the GaN layer and the Si-doped AlGaN layer is greater than that of the Si-doped GaN layer and the InGaN layer.

[0018] The growth rotation speeds of the GaN layer and the Si-doped AlGaN layer are both greater than those of the Si-doped GaN layer and the InGaN layer.

[0019] A second aspect of the present invention also provides a method for preparing the highly hydrolysis-resistant LED epitaxial wafer, comprising:

[0020] Provide a substrate;

[0021] A buffer layer is deposited on the substrate;

[0022] A U-shaped GaN layer is deposited on the buffer layer;

[0023] An N-type semiconductor layer is deposited on the U-shaped GaN layer;

[0024] A superlattice layer is deposited on the N-type semiconductor layer;

[0025] A multi-quantum well layer is deposited on the superlattice layer;

[0026] An electron blocking layer is deposited on the multi-quantum-well layer;

[0027] A P-type semiconductor layer is deposited on the electron blocking layer;

[0028] The N-type semiconductor layer is a periodic structure formed by the alternating growth of GaN and Si-doped AlGaN layers;

[0029] The superlattice layer comprises periodically alternating layers of Si-doped GaN and InGaN.

[0030] As an improvement to the above scheme, in the N-type semiconductor layer, the growth temperature of the GaN layer is 1080℃-1120℃, the growth pressure is 200 torr-400 torr, and the growth rotation speed is 1000 rpm-1200 rpm; the growth temperature of the Si-doped AlGaN layer is 1080℃-1120℃, the growth pressure is 200 torr-400 torr, and the growth rotation speed is 1000 rpm-1200 rpm.

[0031] In the superlattice layer, the Si-doped GaN layer is grown at a temperature of 800℃-850℃, a growth pressure of 100 torr-200 torr, and a growth rotation speed of 400 rpm-600 rpm; the InGaN layer is grown at a temperature of 800℃-850℃, a growth pressure of 100 torr-200 torr, and a growth rotation speed of 400 rpm-600 rpm.

[0032] Implementing this invention has the following beneficial effects:

[0033] In this application, a periodic structure formed by the alternating growth of GaN and Si-doped AlGaN layers is used as the N-type semiconductor layer. Subsequently, a superlattice layer formed by the periodic alternating stacking of Si-doped GaN and InGaN layers is set on the N-type semiconductor layer. By adjusting the epitaxial structure, not only can water molecules be effectively prevented from entering the N-type semiconductor layer and eroding GaN, thus improving the hydrolysis resistance of the blue-green LED epitaxial wafer, but also the cost can be reduced without the need for additional chip processing. Furthermore, the carrier recombination efficiency can be increased, thereby improving the luminous efficiency and reliability of the device. Attached Figure Description

[0034] Figure 1 : A schematic diagram of the structure of a highly hydrolysis-resistant LED epitaxial wafer in this invention;

[0035] Figure 2 : A schematic diagram of the structure of the N-type semiconductor layer in this invention;

[0036] Figure 3 : A schematic diagram of the superlattice layer in this invention.

[0037] Figure label:

[0038] 1-Substrate; 2-Buffer layer; 3-U-type GaN layer; 4-N-type semiconductor layer; 41-GaN layer; 42-Si-doped AlGaN layer; 5-Superlattice layer; 51-Si-doped GaN layer; 52-InGaN layer; 6-Multiple quantum well layer; 7-Electron blocking layer; 8-P-type semiconductor layer. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments will be described in further detail below.

[0040] In the description of this application, it is necessary to understand that the orientation or positional relationship indicated by terms such as "upper", "lower", "top", "bottom", "inner", and "outer" are based on the orientation or positional relationship shown in the accompanying drawings. They are intended only to facilitate the description of the present invention and to simplify the description, and are not intended to indicate or imply that the components referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0041] To address the above problems, the first aspect of this invention provides a highly hydrolysis-resistant LED epitaxial wafer, such as... Figure 1 As shown, the substrate includes a substrate 1, on which a buffer layer 2, a U-type GaN layer 3, an N-type semiconductor layer 4, a superlattice layer 5, a multiple quantum well layer 6, an electron blocking layer 7, and a P-type semiconductor layer 8 are sequentially disposed.

[0042] Among them, such as Figure 2As shown, the N-type semiconductor layer 4 is a periodic structure formed by the alternating growth of GaN layer 41 and Si-doped AlGaN layer 42;

[0043] like Figure 3 As shown, the superlattice layer 5 includes periodically alternating layers of Si-doped GaN layer 51 and InGaN layer 52.

[0044] In this application, a periodic structure formed by the alternating growth of GaN layer 41 and Si-doped AlGaN layer 42 is used as the N-type semiconductor layer 4. Subsequently, a superlattice layer 5 formed by the periodic alternating stacking of Si-doped GaN layer 51 and InGaN layer 52 is set on the N-type semiconductor layer 4. By adjusting the epitaxial structure, not only can water molecules be effectively blocked from entering the N-type semiconductor layer 4 to erode GaN and improve the hydrolysis resistance of the blue-green LED epitaxial wafer without adding additional chip processes and costs, but the carrier recombination efficiency can also be increased, thereby improving the luminous efficiency and reliability of the device.

[0045] Specifically, a periodic structure formed by alternating growth of GaN layer 41 and Si-doped AlGaN layer 42 is used as the N-type semiconductor layer 4. This not only effectively prevents water molecules from entering the N-type semiconductor layer 4 and eroding GaN, but also better expands the current and buffers stress through the different lattices of the alternating layers, thus improving the crystal quality of the N-type semiconductor layer 4. Subsequently, a superlattice layer 5 formed by periodically alternating Si-doped GaN layer 51 and InGaN layer 52 is set on the N-type semiconductor layer 4. This can release the stress superimposed on the N-type semiconductor layer 4, forming a dense barrier layer that prevents water molecules from entering the depth of the N-type semiconductor layer 4, thereby protecting GaN from hydrolysis, maintaining chip performance and stability, and releasing stress during the alternating growth process, reducing defects and dislocations caused by stress concentration. At the same time, due to lattice mismatch, V-shaped pits are formed on the surface, and the sidewalls of the V-shaped pits can form localized potential wells, restricting the diffusion of electrons and holes in the active region, increasing carrier recombination efficiency, and thus improving the luminous efficiency and reliability of the device.

[0046] Preferably, such as Figure 2 As shown, the number of cycles of the N-type semiconductor layer 4 is 40-50, and the total thickness of the N-type semiconductor layer 4 is 1.4μm-1.6μm. Exemplary total thicknesses are 1.4μm, 1.45μm, 1.5μm, 1.55μm, and 1.6μm, but are not limited thereto.

[0047] Furthermore, the surface of the GaN layer 41 is a Ga surface. Although it does not react with water at room temperature or high temperature, the epitaxial layer after Si doping exhibits enhanced N polarity and is highly susceptible to hydrolysis at high temperatures. In this application, Si doping is not performed in the GaN layer 41, but rather in the AlGaN layer, ensuring that the GaN layer 41 is essentially non-hydrolyzed. Moreover, AlGaN does not react with water at low temperatures, but forms an AlOOH structure at high temperatures. This layer prevents water molecules from entering and eroding the GaN, making it less prone to hydrolysis even with Si doping. In a single cycle, the thickness of the GaN layer 41 is 15nm-20nm, and the thickness of the Si-doped AlGaN layer 42 is 15nm-20nm. If the GaN layer 41 is too thick, its dense structure can effectively block the penetration of water molecules and improve hydrolysis resistance, but it may lead to stress accumulation, affecting crystal quality, and may also lead to increased resistance, affecting current spreading performance. If the Si-doped AlGaN layer 42 is too thick, the increased Si doping concentration can improve current spreading performance and form more AlOOH structures, which is beneficial to improving hydrolysis resistance, but it may lead to increased lattice mismatch, generating more defects, reducing hydrolysis resistance, and affecting current spreading performance.

[0048] Furthermore, the Si doping concentration in the Si-doped AlGaN layer 42 is 1×10⁻⁶. 19 atoms / cm 3 -2×10 19 atoms / cm 3 While ensuring hydrolysis resistance, it can improve electron concentration and mobility. The Al component ratio is 0.1-0.2%, which promotes the formation of AlOOH structure, thereby improving the hydrolysis resistance of epitaxial wafer. Moreover, the combination with periodic structure can reduce the dislocation density of GaN layer, thereby improving crystal quality, current spreading performance, increasing the luminous brightness of LED device and reducing operating voltage.

[0049] Preferably, such as Figure 3 As shown, the superlattice layer 5 has 3-6 periods, and the total thickness of the superlattice layer 5 is [missing information]. An exemplary total thickness is But it is not limited to this.

[0050] Furthermore, in the superlattice layer 5, the Si-doped GaN layer 51 introduces Si impurities, increasing the concentration of free electrons in GaN, reducing the device resistance, facilitating current expansion over a wider area, and improving current injection efficiency and device uniformity. Meanwhile, the InGaN layer 52 increases structural complexity and diversity, more effectively releasing stress between epitaxial layers, reducing defects and dislocations caused by stress concentration, and serving as a potential well for charge carriers, providing additional carrier storage space and contributing to improved carrier injection and transport efficiency. In a single cycle, the thickness ratio of the Si-doped GaN layer 51 to the InGaN layer 52 is (4-10):1.

[0051] In some specific and preferred embodiments, the thickness of the Si-doped GaN layer 51 is The thickness of the InGaN layer 52 is

[0052] Preferably, in the superlattice layer 5, the Si doping concentration in the Si-doped GaN layer 51 is lower than the Si doping concentration in the Si-doped AlGaN layer 42, which can improve current spread. The growth temperature of the Si-doped GaN layer 51 is lower than that of the N-type semiconductor layer, and excessively high Si concentration will degrade the crystal quality of the layer.

[0053] Furthermore, in the superlattice layer 5, the Si doping concentration in the Si-doped GaN layer 51 is 4 × 10⁻⁶. 18 atoms / cm 3 -5×10 18 atoms / cm 3 The InGaN layer 52 has an In content of 0.1-0.2%.

[0054] In some specific and preferred embodiments, the growth temperatures of the GaN layer 41 and the Si-doped AlGaN layer 42 are both higher than the growth temperatures of the Si-doped GaN layer 51 and the InGaN layer 52; the growth pressures of the GaN layer 41 and the Si-doped AlGaN layer 42 are both higher than the growth pressures of the Si-doped GaN layer 51 and the InGaN layer 52; and the growth rotation speeds of the GaN layer 41 and the Si-doped AlGaN layer 42 are both higher than the growth rotation speeds of the Si-doped GaN layer 51 and the InGaN layer 52. This promotes effective doping of Si and In, suppresses phase separation of Al and Ga in the Si-doped AlGaN layer 42, improves the uniformity of the material, reduces defects caused by lattice mismatch, and thus improves the crystal quality and hydrolysis resistance of the N-type semiconductor layer 4 and the superlattice layer 5, further improving the luminous performance of the LED device.

[0055] Accordingly, the present invention also provides a method for preparing the highly hydrolysis-resistant LED epitaxial wafer, comprising:

[0056] (1) Provide a substrate 1;

[0057] Optionally, the substrate 1 includes, but is not limited to, a sapphire substrate; preferably, a patterned sapphire substrate (sapphire PSS substrate).

[0058] (2) Deposit a buffer layer 2 on the substrate 1;

[0059] Preferably, the buffer layer 2 is an AlN layer, and the thickness of the buffer layer 2 is 16nm-20nm.

[0060] Furthermore, the buffer is grown using chemical vapor deposition (CVD), specifically:

[0061] The substrate 1 is placed in a CVD setup, the growth temperature is adjusted to 600℃-700℃, the Ar to N2 flow rate ratio is 4:1-6:1, the oxygen flow rate is 1sccm-2sccm, and an Al target is introduced to deposit the buffer layer 2.

[0062] (3) Deposit a U-shaped GaN layer 3 on the buffer layer 2;

[0063] Preferably, the thickness of the U-shaped GaN layer 3 is 2μm-3μm.

[0064] Furthermore, the U-shaped GaN layer 3 is grown using metal-organic chemical vapor deposition (MOCVD), specifically:

[0065] The substrate 1 with the buffer layer 2 deposited is placed in an MOCVD device, and the growth temperature is adjusted to 1100℃-1150℃, the growth pressure to 100 torr-200 torr, and the growth speed to 1000 rpm-1500 rpm. H2 is introduced as the carrier gas, and then N source and Ga source are introduced to grow the U-shaped GaN layer 3.

[0066] Understandably, the subsequent layer structures of the epitaxial wafer are all completed in the MOCVD settings.

[0067] (4) Deposit an N-type semiconductor layer 4 on the U-type GaN layer 3;

[0068] Preferably, the N-type semiconductor layer 4 is a periodic structure formed by alternating growth of GaN layer 41 and Si-doped AlGaN layer 42.

[0069] Furthermore, depositing the N-type semiconductor layer 4 specifically includes:

[0070] The growth temperature was adjusted to 1080℃-1120℃, the growth pressure to 200 torr-400 torr, and the growth speed to 1000 rpm-1200 rpm. H2 was introduced as the carrier gas, followed by the introduction of N source and Ga source to grow GaN layer 41 for 5s-8s. Then, Si-doped AlGaN layer 42 was grown through Si source, Al source, N source and Ga source for 5s-8s. This completed one cycle of growth. Finally, the layer growth was repeated according to the preset number of cycles to obtain N-type semiconductor layer 4 with a periodic structure.

[0071] (5) Deposit a superlattice layer 5 on the N-type semiconductor layer 4;

[0072] Preferably, the superlattice layer 5 comprises periodically alternating layers of Si-doped GaN layer 51 and InGaN layer 52.

[0073] Furthermore, the deposition of the superlattice layer 5 specifically includes:

[0074] The growth temperature was adjusted to 800℃-850℃, the growth pressure to 100 torr-200 torr, and the growth speed to 400 rpm-600 rpm. N2 was introduced as the carrier gas, followed by the introduction of Si, N and Ga sources to grow the Si-doped GaN layer 51. Then, the InGaN layer 52 was grown through the In, N and Ga sources, completing one cycle of growth. Finally, the layer growth was repeated according to the preset number of cycles to obtain the superlattice layer 5 with a periodic structure.

[0075] In this application, Si-doped GaN layer 51 and InGaN layer 52 are grown at low temperature, which promotes the formation of surface V-shaped pits. The sidewalls of the V-shaped pits are then used to form localized potential wells, which can limit the diffusion of electrons and holes in the active region and increase carrier recombination efficiency.

[0076] (6) Deposit a multi-quantum well layer 6 on the superlattice layer 5;

[0077] Preferably, the multiple quantum well layer 6 is a periodic structure of alternating InGaN quantum well layers and Si-doped GaN quantum barrier layers, with a stacking period of 8-10, and the total thickness of the multiple quantum well layer 6 is [missing information]. Within a single cycle, the In composition of the InGaN quantum well layer is 0.1-0.2 (blue) or 0.25-0.35 (green), and the thickness of the InGaN quantum well layer is [missing information]. The Si doping concentration in the Si-doped GaN quantum barrier layer is 1×10⁻⁶. 18 atoms / cm 3 -2×10 18 atoms / cm 3The thickness of the Si-doped GaN quantum barrier layer is

[0078] Furthermore, depositing the multi-quantum-well layer 6 specifically includes:

[0079] The growth temperature was adjusted to 750℃-800℃, the growth pressure to 100 torr-200 torr, and the growth speed to 400 rpm-600 rpm. N2 was introduced as the carrier gas, followed by the introduction of In source, N source and Ga source to grow the InGaN quantum well layer. Then, the Si-doped GaN quantum barrier layer was grown through Si source, N source and Ga source. At this time, one cycle of growth was completed. Finally, the layer growth was repeated according to the preset number of cycles to obtain a multi-quantum well layer 6 with a periodic structure.

[0080] (7) Deposit an electron blocking layer 7 on the multi-quantum well layer 6;

[0081] Preferably, the electron blocking layer 7 is an AlGaN layer, wherein the Al component accounts for 0.2-0.3%, which can effectively prevent electron overflow, and the total thickness of the electron blocking layer 7 is 40nm-60nm.

[0082] Furthermore, depositing the electron blocking layer 7 specifically includes:

[0083] The growth temperature was adjusted to 950℃-1000℃, the growth pressure to 100 torr-200 torr, and the growth speed to 1000 rpm-1200 rpm. N2 was introduced as the carrier gas, followed by the introduction of Al, N and Ga sources to grow the electron blocking layer 7.

[0084] (8) Deposit a P-type semiconductor layer 8 on the electron blocking layer 7;

[0085] Preferably, the P-type semiconductor layer 8 is a P-type GaN layer, and the P-type dopant is preferably Mg, with a doping concentration of 2 × 10⁻⁶. 19 atoms / cm 3 -3×10 19 atoms / cm 3 The thickness of the P-type semiconductor layer 8 is 200nm-300nm, which allows the V-shaped pits to be filled.

[0086] Furthermore, depositing the P-type semiconductor layer 8 specifically includes:

[0087] The growth temperature was adjusted to 900℃-980℃, the growth pressure to 100 torr-200 torr, and the growth speed to 500 rpm-1200 rpm. H2 was introduced as the carrier gas, followed by the introduction of Mg source, N source and Ga source to grow the P-type semiconductor layer 8.

[0088] It should be noted that in this invention, the N source can be high-purity NH3, the Al source can be TMAl (trimethylaluminum), the Ga source can be TEGa (triethylgallium), the In source can be TMIn (trimethylindium), the Si source can be SiH4, and the Mg source can be CP2Mg.

[0089] The present invention will be further described below with reference to specific embodiments:

[0090] Example 1

[0091] This embodiment provides a blue LED epitaxial wafer with high resistance to hydrolysis, including a substrate, on which a buffer layer, a U-type GaN layer, an N-type semiconductor layer, a superlattice layer, a multiple quantum well layer, an electron blocking layer and a P-type semiconductor layer are sequentially disposed;

[0092] The N-type semiconductor layer is a periodic structure formed by alternating growth of GaN and Si-doped AlGaN layers; the number of periods is 45; the thickness of the GaN layer is 17 nm; the thickness of the Si-doped AlGaN layer is 18 nm; and the Si doping concentration is 1.5 × 10⁻⁶. 19 atoms / cm 3 The Al component accounts for 0.15%, and the total thickness of the N-type semiconductor layer is 1.575 μm.

[0093] The superlattice layer comprises periodically alternating layers of Si-doped GaN and InGaN, with a period number of 5. The thickness of the Si-doped GaN layer is [missing information]. The Si doping concentration is 1×10 19 atoms / cm 3 The thickness of the InGaN layer is The In composition ratio is 0.15, and the total thickness of the superlattice layer is...

[0094] The method for preparing the blue light highly hydrolysis-resistant LED epitaxial wafer includes:

[0095] (1) Provide a substrate;

[0096] The substrate is a sapphire PSS substrate.

[0097] (2) Deposit a buffer layer on the substrate;

[0098] The buffer layer is an AlN layer with a thickness of 18 nm.

[0099] Specifically: the substrate is placed in a CVD setup, the growth temperature is adjusted to 650°C, the Ar to N2 flow rate ratio is 5:1, the oxygen flow rate is 1.5 sccm, and an Al target is introduced to deposit a buffer layer.

[0100] (3) Deposit a U-shaped GaN layer on the buffer layer;

[0101] The thickness of the U-shaped GaN layer is 2.5 μm.

[0102] Specifically: The substrate with the deposited buffer layer is placed in the MOCVD equipment, the growth temperature is adjusted to 1125℃, the growth pressure is 150 torr, the growth speed is 1250 rpm, H2 is introduced as the carrier gas, and then N source and Ga source are introduced to grow the U-shaped GaN layer.

[0103] (4) Deposit an N-type semiconductor layer on the U-type GaN layer;

[0104] The N-type semiconductor layer is a periodic structure formed by the alternating growth of GaN and Si-doped AlGaN layers.

[0105] Specifically: the growth temperature was adjusted to 1100℃, the growth pressure to 300 torr, and the growth speed to 1100 rpm. H2 was introduced as the carrier gas, followed by the introduction of N source and Ga source to grow the GaN layer. Then, the Si-doped AlGaN layer was grown through Si source, Al source, N source and Ga source. At this point, one cycle of growth was completed. Finally, the stacked growth was repeated for 44 cycles to obtain an N-type semiconductor layer with a periodic structure.

[0106] (5) Deposit a superlattice layer on the N-type semiconductor layer;

[0107] The superlattice layer comprises periodically alternating layers of Si-doped GaN and InGaN.

[0108] Specifically: the growth temperature was adjusted to 825℃, the growth pressure to 150 torr, and the growth speed to 500 rpm. N2 was introduced as the carrier gas, followed by the introduction of Si, N and Ga sources to grow the Si-doped GaN layer. Then, the InGaN layer was grown through the In, N and Ga sources, thus completing one cycle of growth. Finally, the stacked growth was repeated for 4 cycles to obtain a superlattice layer with a periodic structure.

[0109] (6) Deposit a multi-quantum-well layer on the superlattice layer;

[0110] The multiple quantum well layer is a periodic structure consisting of alternating InGaN quantum well layers and Si-doped GaN quantum barrier layers, with a stacking period of 9. Within a single period, the InGaN quantum well layer has an In composition of 0.15, and its thickness is [missing information]. The Si doping concentration in the Si-doped GaN quantum barrier layer is 1.5 × 10⁻⁶. 18 atoms / cm 3The thickness of the Si-doped GaN quantum barrier layer is The total thickness of the multi-quantum-well layer is

[0111] Specifically: the growth temperature was adjusted to 775℃, the growth pressure to 150 torr, and the growth speed to 500 rpm. N2 was introduced as the carrier gas, followed by the introduction of In source, N source and Ga source to grow the InGaN quantum well layer; then, the Si-doped GaN quantum barrier layer was grown through Si source, N source and Ga source, which completed one cycle of growth. Finally, the stacked growth was repeated for 8 cycles to obtain a multi-quantum well layer with a periodic structure.

[0112] (7) Deposit an electron blocking layer on the multi-quantum-well layer;

[0113] The electron blocking layer is an AlGaN layer, wherein the Al component accounts for 0.25% and the thickness of the electron blocking layer is 50 nm.

[0114] Specifically: the growth temperature was adjusted to 975℃, the growth pressure to 150 torr, the growth speed to 1100 rpm, and N2 was introduced as the carrier gas. Then, Al source, N source and Ga source were introduced to grow the electron blocking layer.

[0115] (8) Deposit a P-type semiconductor layer on the electron blocking layer;

[0116] The P-type semiconductor layer is a P-type GaN layer, the P-type dopant is Mg, and the doping concentration of the P-type dopant is 2.5 × 10⁻⁶. 19 atoms / cm 3 The thickness of the P-type semiconductor layer is 250 nm.

[0117] Specifically: the growth temperature was adjusted to 940℃, the growth pressure to 150 torr, the growth speed to 800 rpm, and H2 was introduced as the carrier gas. Then, Mg source, N source and Ga source were introduced to grow the P-type semiconductor layer.

[0118] Example 2

[0119] This embodiment provides a blue LED epitaxial wafer with high resistance to hydrolysis, which is basically the same as that in Embodiment 1, except that:

[0120] In the superlattice layer, the Si doping concentration of the Si-doped GaN layer is 4.5 × 10⁻⁶. 18 atoms / cm 3 .

[0121] Example 3

[0122] This embodiment provides a blue LED epitaxial wafer with high resistance to hydrolysis, which is basically the same as that in Embodiment 2, except that:

[0123] The thickness of the GaN layer is 15 nm, the thickness of the Si-doped AlGaN layer is 15 nm, and the total thickness of the N-type semiconductor layer is 1.35 μm.

[0124] Example 4

[0125] This embodiment provides a blue LED epitaxial wafer with high resistance to hydrolysis, which is basically the same as that in Embodiment 2, except that:

[0126] In the superlattice layer, the thickness of the Si-doped GaN layer is The thickness of the InGaN layer is The total thickness of the superlattice layer is

[0127] Comparative Example 1

[0128] This comparative example provides a blue LED epitaxial wafer with high resistance to hydrolysis, which is basically the same as that in Example 1, except that:

[0129] The N-type semiconductor layer is a Si-doped GaN layer with a Si doping concentration of 1.5 × 10⁻⁶. 19 atoms / cm 3 The thickness is 1.575μm.

[0130] Comparative Example 2

[0131] This comparative example provides a blue LED epitaxial wafer with high resistance to hydrolysis, which is basically the same as that in Example 1, except that:

[0132] The N-type semiconductor layer is a periodic structure formed by alternating growth of GaN layers and Si-doped GaN layers; the number of periods is 45, the thickness of the GaN layer is 17 nm, the thickness of the Si-doped GaN layer is 18 nm, and the Si doping concentration is 1.5 × 10⁻⁶. 19 atoms / cm 3 The total thickness of the N-type semiconductor layer is 1.575 μm.

[0133] Example 5

[0134] This embodiment provides a green LED epitaxial wafer with high resistance to hydrolysis, which is basically the same as that in Embodiment 1, except that:

[0135] The multiple quantum well layer is a periodic structure consisting of alternating InGaN quantum well layers and Si-doped GaN quantum barrier layers, with a stacking period of 9. Within a single period, the InGaN quantum well layer has an In composition of 0.3, and its thickness is [missing information]. The Si doping concentration in the Si-doped GaN quantum barrier layer is 1.5 × 10⁻⁶.18 atoms / cm 3 The thickness of the Si-doped GaN quantum barrier layer is The total thickness of the multi-quantum-well layer is

[0136] Example 6

[0137] This embodiment provides a green LED epitaxial wafer with high resistance to hydrolysis, which is basically the same as that in Embodiment 5, except that:

[0138] In the superlattice layer, the Si doping concentration of the Si-doped GaN layer is 4.5 × 10⁻⁶. 18 atoms / cm 3 .

[0139] Comparative Example 3

[0140] This comparative example provides a green LED epitaxial wafer with high resistance to hydrolysis, which is basically the same as that in Example 5, except that:

[0141] The N-type semiconductor layer is a Si-doped GaN layer with a Si doping concentration of 1.5 × 10⁻⁶. 19 atoms / cm 3 The thickness is 1.575μm.

[0142] Comparative Example 4

[0143] This comparative example provides a green LED epitaxial wafer with high resistance to hydrolysis, which is basically the same as that in Example 5, except that:

[0144] The N-type semiconductor layer is a periodic structure formed by alternating growth of GaN layers and Si-doped GaN layers; the number of periods is 45, the thickness of the GaN layer is 17 nm, the thickness of the Si-doped GaN layer is 18 nm, and the Si doping concentration is 1.5 × 10⁻⁶. 19 atoms / cm 3 The total thickness of the N-type semiconductor layer is 1.575 μm.

[0145] Performance testing

[0146] 1. Hydrolysis resistance: The LED epitaxial wafers obtained in the examples and comparative examples were made into LED beads with a size of 08mil*08mil and tested for lighting. Subsequently, the obtained LED beads were subjected to a hydrolysis resistance test (high temperature and high humidity, temperature 85℃, humidity 85%, reverse voltage -10V) for 336 hours, and the lighting performance of the obtained chips was tested. The test results are shown in Table 1 below.

[0147] Table 1 Results of hydrolysis resistance test

[0148]

[0149]

[0150] The results above show that by using a periodic structure formed by alternating growth of GaN and Si-doped AlGaN layers as the N-type semiconductor layer, and then setting a superlattice layer formed by periodically alternating Si-doped GaN and InGaN layers on the N-type semiconductor layer, the epitaxial structure can effectively prevent water molecules from entering the N-type semiconductor layer and eroding GaN, thereby improving the hydrolysis resistance of the blue-green LED epitaxial wafer, enabling it to achieve 336 hours without LED failure, and without the need for additional chip processing.

[0151] 2. The LED epitaxial wafers obtained in the examples and comparative examples were made into 08mil*08mil LED beads, and their luminous brightness and forward voltage were tested. The test results are shown in Table 2.

[0152] Table 2 Test results of luminous intensity and forward voltage

[0153] Luminous brightness Forward voltage (V) Example 1 8.01 2.90 Example 2 8.05 2.88 Example 3 7.95 2.91 Example 4 7.89 2.89 Comparative Example 1 7.92 2.93 Comparative Example 2 7.86 2.92 Example 5 6.20 2.81 Example 6 6.25 2.76 Comparative Example 3 6.13 2.76 Comparative Example 4 6.18 2.83

[0154] The results above show that by using a periodic structure formed by alternating growth of GaN and Si-doped AlGaN layers as the N-type semiconductor layer, and then setting a superlattice layer formed by periodically alternating Si-doped GaN and InGaN layers on the N-type semiconductor layer, the current spreading performance can be effectively improved by adjusting the epitaxial structure, thereby improving the electrical performance of the LED chip.

[0155] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A highly hydrolysis-resistant LED epitaxial wafer, characterized in that, The substrate includes a buffer layer, a U-type GaN layer, an N-type semiconductor layer, a superlattice layer, a multiple quantum well layer, an electron blocking layer, and a P-type semiconductor layer, which are sequentially disposed on the substrate. The N-type semiconductor layer is a periodic structure formed by the alternating growth of GaN and Si-doped AlGaN layers; The superlattice layer comprises periodically alternating layers of Si-doped GaN and InGaN.

2. The highly hydrolysis-resistant LED epitaxial wafer as described in claim 1, characterized in that, The number of periods of the N-type semiconductor layer is 40-50, and the total thickness of the N-type semiconductor layer is 1.4μm-1.6μm.

3. The highly hydrolysis-resistant LED epitaxial wafer as described in claim 2, characterized in that, In a single cycle, the thickness of the GaN layer is 15nm-20nm, and the thickness of the Si-doped AlGaN layer is 15nm-20nm.

4. The highly hydrolysis-resistant LED epitaxial wafer as described in any one of claims 1-3, characterized in that, In the N-type semiconductor, the Si doping concentration in the Si-doped AlGaN layer is 1×10⁻⁶. 19 atoms / cm 3 -2×10 19 atoms / cm 3 The Al component accounts for 0.1-0.2%.

5. The highly hydrolysis-resistant LED epitaxial wafer as described in claim 1, characterized in that, The superlattice layer has 3-6 periods, and the total thickness of the superlattice layer is [missing information]. In a single cycle, the thickness ratio of the Si-doped GaN layer to the InGaN layer is (4-10):

1.

6. The highly hydrolysis-resistant LED epitaxial wafer as described in claim 4, characterized in that, The Si doping concentration in the Si-doped GaN layer is lower than the Si doping concentration in the Si-doped AlGaN layer.

7. The highly hydrolysis-resistant LED epitaxial wafer as described in claim 6, characterized in that, The Si doping concentration in the Si-doped GaN layer is 4 × 10⁻⁶. 18 atoms / cm 3 -5×10 18 atoms / cm 3 ; The InGaN layer contains 0.1-0.2% In content.

8. The highly hydrolysis-resistant LED epitaxial wafer as described in claim 1, characterized in that, The growth temperatures of the GaN layer and the Si-doped AlGaN layer are both higher than those of the Si-doped GaN layer and the InGaN layer. The growth pressure of the GaN layer and the Si-doped AlGaN layer is greater than that of the Si-doped GaN layer and the InGaN layer. The growth rotation speeds of the GaN layer and the Si-doped AlGaN layer are both greater than those of the Si-doped GaN layer and the InGaN layer.

9. A method for preparing a highly hydrolysis-resistant LED epitaxial wafer as described in any one of claims 1-8, characterized in that, include: Provide a substrate; A buffer layer is deposited on the substrate; A U-shaped GaN layer is deposited on the buffer layer; An N-type semiconductor layer is deposited on the U-shaped GaN layer; A superlattice layer is deposited on the N-type semiconductor layer; A multi-quantum well layer is deposited on the superlattice layer; An electron blocking layer is deposited on the multi-quantum-well layer; A P-type semiconductor layer is deposited on the electron blocking layer; The N-type semiconductor layer is a periodic structure formed by the alternating growth of GaN and Si-doped AlGaN layers; The superlattice layer comprises periodically alternating layers of Si-doped GaN and InGaN.

10. The method for preparing a highly hydrolysis-resistant LED epitaxial wafer as described in claim 9, characterized in that, In the N-type semiconductor layer, the GaN layer is grown at a temperature of 1080℃-1120℃, a growth pressure of 200 torr-400 torr, and a growth rotation speed of 1000 rpm-1200 rpm; the Si-doped AlGaN layer is grown at a temperature of 1080℃-1120℃, a growth pressure of 200 torr-400 torr, and a growth rotation speed of 1000 rpm-1200 rpm. In the superlattice layer, the growth temperature of the Si-doped GaN layer is 800℃-850℃, the growth pressure is 100 torr-200 torr, and the growth rotation speed is 400 rpm-600 rpm; the growth temperature of the InGaN layer is 800℃-850℃, the growth pressure is 100 torr-200 torr, and the growth rotation speed is 400 rpm-600 rpm.

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