Preparation method for current blocking layer, and LED chip

Abstract

Disclosed in the present application are a preparation method for a current barrier layer, and an LED chip. The preparation method comprises: using a first PECVD process to make a first SiO2 thin film on a substrate; and using a second PECVD process in situ to deposit a second SiO2 thin film on a surface of the first SiO2 thin film, wherein the first PECVD process uses high-frequency radio frequency power; the second PECVD process uses high-frequency and low-frequency double-frequency radio frequency power; and the high-frequency radio frequency power used by the first PECVD process is lower than the high-frequency radio frequency power used by the second PECVD process. A current blocking layer made in the present application has relatively high insulating property and compactness, and can also avoid damage to a P-type semiconductor layer.

Description

A preparation method of current blocking layer and LED chip Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a method for preparing a current blocking layer and an LED chip. Background Art

[0002] Figure 1 is a schematic diagram of the structure of a conventional LED chip. As shown in Figure 1 , from bottom to top, it includes a substrate 10, an N-type semiconductor layer 20, a multiple quantum well layer 30 (MQW), a P-type semiconductor layer 40, a conductive layer 50, a P-electrode 60 connected to the conductive layer 50, and an N-electrode 70 connected to the N-type semiconductor layer 20. A current blocking layer 80 is provided between the P-type semiconductor layer 40 and the conductive layer 50, facing the P-electrode 60.

[0003] P-type carriers and N-type carriers recombine in the multi-quantum well layer 30 to generate photons. The N-type semiconductor layer 20, the multi-quantum well layer 30, and the P-type semiconductor layer 40 constitute the light-emitting functional layer of the LED chip. The current blocking layer 80 is generally a SiO2 thin film, which can prevent the current generated by the P electrode 60 from diffusing toward the conductive layer 50 in the area directly below, increasing the current density in other areas of the conductive layer 50, thereby reducing the P electrode 60's blockage and absorption of light, better extracting photons from the LED chip, and improving the current distribution on the conductive layer 50, thereby alleviating the current crowding phenomenon below the P electrode 60 and improving the internal quantum efficiency and light extraction efficiency of the LED chip. This requires the SiO2 film to have a high dielectric constant (insulation) and high density.

[0004] Currently, SiO2 films are mainly produced using the Plasma Enhanced Chemical Vaper Deposition (PECVD) process. Deposition is performed at high RF power and low RF frequency. Although this can improve the insulation and density of the SiO2 film, it will damage the P-type semiconductor layer 40. In order to avoid damaging the P-type semiconductor layer 40, if low RF power and high RF frequency are used for deposition, the insulation and density of the SiO2 film will be reduced.

[0005] Summary of the Invention

[0006] In response to the above technical problems, the present application provides a method for preparing a current blocking layer and an LED chip, which can improve the problem that the existing process for manufacturing the current blocking layer cannot take into account both avoiding damage to the P-type semiconductor layer and ensuring the insulation and density of the current blocking layer.

[0007] To solve the above technical problems, in a first aspect, an embodiment of the present application provides a method for preparing a current blocking layer, comprising:

[0008] forming a first SiO2 thin film on a substrate by a first PECVD process;

[0009] Depositing a second SiO2 film on the surface of the first SiO2 film using a second PECVD process in situ;

[0010] Among them, the first PECVD process adopts high-frequency RF power, the second PECVD process adopts high-frequency-low-frequency dual-frequency RF power, and the high-frequency RF power adopted by the first PECVD process is lower than the high-frequency RF power adopted by the second PECVD process.

[0011] In some embodiments, in the first PECVD process, the high-frequency RF power is 10W-50W, and the high-frequency RF frequency is 10MHz-60MHz.

[0012] In some embodiments, in the second PECVD process, the high-frequency RF power is 200W-700W, and the high-frequency RF frequency is 10MHz-60MHz.

[0013] In some embodiments, in the second PECVD process, the low-frequency RF power is 80W-300W, and the low-frequency RF frequency is 100KHz-500KHz.

[0014] In some embodiments, the reaction gases used in the first PECVD process and the second PECVD process include SiH4, N2O and N2.

[0015] In some embodiments, after depositing a second SiO2 film on the surface of the first SiO2 film using a second PECVD process in situ, the method further includes:

[0016] A surface treatment gas is introduced in situ and ignited to form plasma, so as to perform surface treatment on the second SiO2 film to reduce the conductivity of the surface of the second SiO2 film.

[0017] In some embodiments, after forming the first SiO2 film on the substrate using the first PECVD process, the method further includes:

[0018] A surface treatment gas is introduced in situ and ignited to form plasma, so as to perform surface treatment on the first SiO2 film to reduce the surface conductivity of the first SiO2 film.

[0019] In some embodiments, the surface treatment gas includes He and O2.

[0020] In some embodiments, in the surface treatment process, the ignition radio frequency power is 100W-500W, and the radio frequency is 13.56MHz.

[0021] In some embodiments, the flow rate of He is 5000 sccm-8000 sccm, and the ratio of the flow rate of He to the flow rate of O 2 is 2000:1-5000:1.

[0022] In some embodiments, during the surface treatment process, the chamber pressure is 800 mT-1500 mT.

[0023] In some embodiments, in the first PECVD process, the flow rate of SiH4 is 5 sccm-35 sccm, the flow rate of N2O is 500 sccm-1700 sccm, and the flow rate of N2 is 800 sccm-2400 sccm.

[0024] In some embodiments, during the first PECVD process, the chamber pressure is 400 mT-1200 mT.

[0025] In some embodiments, in the second PECVD process, the flow rate of SiH4 is 10 sccm-60 sccm, the flow rate of N2O is 1000 sccm-3000 sccm, and the flow rate of N2 is 900 sccm-2800 sccm.

[0026] In some embodiments, during the second PECVD process, the chamber pressure is 600 mT-1200 mT.

[0027] In a second aspect, an embodiment of the present application provides an LED chip, comprising a substrate and an N-type semiconductor layer, a multi-quantum well layer, a P-type semiconductor layer, a conductive layer, a P-electrode connected to the conductive layer, and an N-electrode connected to the N-type semiconductor layer, which are arranged in sequence on the substrate in a direction away from the substrate. A current blocking layer is provided in an area between the P-type semiconductor layer and the conductive layer facing the P-electrode, and the current blocking layer is prepared using the preparation method described in the above embodiments.

[0028] As described above, the preparation method of the current blocking layer provided by the present application divides the entire current blocking layer into two layers (a first SiO2 film and a second SiO2 film) for preparation, and uses two PECVD processes. First, the first PECVD process uses high-frequency RF power, and the high-frequency RF power used in the first PECVD process is lower than that in the second PECVD process, that is, the first SiO2 film is prepared by the first PECVD process with low RF power and high RF frequency (HF), which can avoid the high-energy particles generated by the traditional low RF frequency (LF) preparation process from damaging the surface of the P-type semiconductor layer. Then, the second PECVD process is used. The VD process uses a high-frequency and low-frequency dual-frequency RF power, and uses a higher high-frequency RF power than the first PECVD process. That is, the second PECVD process uses a high-frequency and low-frequency dual-frequency in situ to deposit the second SiO2 film on the surface of the first SiO2 film. The high-frequency portion can obtain a higher density plasma to improve the deposition efficiency and thickness uniformity of the second SiO2 film. The low-frequency portion can enhance the bombardment of the first and second SiO2 films, improving the density of the films. The first SiO2 film can also serve as a protective layer to prevent the high-energy particles generated by the low-frequency portion from directly bombarding the P-type semiconductor layer and causing damage. The current blocking layer produced in this embodiment not only has high insulation and density, but also can avoid damage to the P-type semiconductor layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings herein are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present application, and together with the specification, are used to explain the principles of the present application. In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for describing the embodiments. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without inventive work.

[0030] FIG1 is a schematic structural diagram of an existing LED chip;

[0031] FIG2 is a schematic flow chart of a method for preparing a current blocking layer according to an embodiment of the present application;

[0032] FIG3 is a schematic flow chart of a method for preparing a current blocking layer according to another embodiment of the present application;

[0033] FIG4 is a schematic diagram of a preferred method for preparing a current blocking layer provided in an embodiment of the present application.

[0034] The purpose of this application, its features, and advantages will be further described in conjunction with the embodiments and with reference to the accompanying drawings. The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and the accompanying text are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of this application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0035] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0036] It should be noted that, in this document, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element. In addition, components, features, and elements with the same name in different embodiments of the present application may have the same meaning or different meanings, and their specific meanings need to be determined by their explanation in the specific embodiment or further combined with the context of the specific embodiment.

[0037] It should be further understood that the terms "comprising" and "including" indicate the presence of the described features, steps, operations, elements, components, items, kinds, and / or groups, but do not exclude the presence, occurrence, or addition of one or more other features, steps, operations, elements, components, items, kinds, and / or groups. The terms "or", "and / or", "including at least one of the following", etc. used in this application may be interpreted as inclusive, or mean any one or any combination. For example, "including at least one of the following: A, B, C" means "any one of the following: A; B; C; A and B; A and C; B and C; A and B and C", and for another example, "A, B or C" or "A, B and / or C" means "any one of the following: A; B; C; A and B; A and C; B and C; A and B and C". Exceptions to this definition will only occur when the combination of elements, functions, steps or operations is inherently mutually exclusive in some way.

[0038] It should be understood that although the terms first, second, third, etc. may be used herein to describe various information, such information should not be limited to these terms. These terms are merely used to distinguish information of the same type from one another. For example, first information could also be referred to as second information, and similarly, second information could also be referred to as first information without departing from the scope of this document. Depending on the context, as used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context indicates otherwise.

[0039] It should be understood that the terms "top", "bottom", "up", "down", "vertical", "horizontal", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0040] Before preparing the current blocking layer of this embodiment, a light-emitting functional layer may be formed on the surface of the substrate.

[0041] In some embodiments, as shown in FIG. 1 , the substrate 10 may be made of sapphire, silicon carbide, silicon, a silicon-containing substrate, an epitaxial silicon substrate, silicon on insulator (SOI), lithium niobate, diamond, or other materials.

[0042] The light-emitting functional layer may include an N-type semiconductor layer 20, a multi-quantum well layer 30, and a P-type semiconductor layer 40, formed sequentially on the surface of the substrate 10 from bottom to top. P-type carriers in the P-type semiconductor layer 40 recombine with N-type carriers in the N-type semiconductor layer 20 in the multi-quantum well layer 30 to generate photons. Therefore, the multi-quantum well layer 30 is also called a light-emitting layer. The current blocking layer of the present application is located on the surface of the P-type semiconductor layer 40.

[0043] As an example, the substrate 10 may be a conventional patterned sapphire substrate (CPSS), the N-type semiconductor layer 20 may be N-GaN, and the P-type semiconductor layer 40 may be P-GaN.

[0044] Please refer to FIG. 2 , which is a schematic flow chart of a method for preparing a current blocking layer provided by an embodiment of the present application. The preparation method may include step S110 and step S120 .

[0045] S110, forming a first SiO2 thin film on the substrate by using a first PECVD process;

[0046] Plasma Enhanced Chemical Vapour Deposition (PECVD) is a method of preparing thin films on substrates by using plasma formed by glow discharge to influence the deposition process during low-pressure chemical vapor deposition.

[0047] The first PECVD process uses high-frequency RF power, and the high-frequency RF power used in the first PECVD process is lower than that in the second PECVD process. That is, the first SiO2 film is prepared by the first PECVD process using low RF power and high RF frequency (HF). This can avoid the high-energy particles generated by the traditional low RF frequency (LF) preparation process from damaging the surface of the P-type semiconductor layer.

[0048] In some embodiments, the reaction gases used in the first PECVD process include SiH 4 , N 2 O, and N 2 .

[0049] In this embodiment, SiH4, N2O, and N2 are used as reaction gases, with N2 serving as a diluent gas. The Si source provided by SiH4 and the O source provided by N2O react to generate SiO2. A first SiO2 film can be formed on a localized region of the top surface of the P-type semiconductor layer of the substrate. As described above, when a conventional PECVD process is used to produce a SiO2 film, high RF power and low RF frequency can damage the P-type semiconductor layer 40. This is because the plasma density excited by a low RF frequency power source is low, the free path of the particles is long, the probability of collision between the particles is low, and the bombardment energy of the particles on the P-type semiconductor layer 40 is high, thereby damaging the surface of the P-type semiconductor layer.

[0050] In some embodiments, in the first PECVD process, the high-frequency RF power is 10W-50W, and the high-frequency RF frequency is 10MHz-60MHz.

[0051] In the first PECVD process of this embodiment, a high-frequency RF power is used. The high-frequency RF power used in the first PECVD process is lower than that used in the second PECVD process, thereby preventing ion bombardment from damaging the surface of the P-type semiconductor layer. For example, the high-frequency RF power may be 10W-50W, and the high-frequency RF frequency may be 10MHz-60MHz. For example, the high RF frequency (HF) may be a commonly used RF frequency of 13.56MHz.

[0052] In one embodiment, in the preparation step of the first SiO2 film, the flow rate of SiH4 can be 5sccm-35sccm, the flow rate of N2O can be 500sccm-1700sccm, and the flow rate of N2 can be 800sccm-2400sccm. As an example, the chamber can be evacuated to achieve a background vacuum (for example, 3mT-5mT), and the deposition temperature range of the first SiO2 film is set to 100°C-200°C. SiH4, N2O and N2 of the above flow rates are used as reaction gases, and the deposition reaction is carried out under the conditions of a high-frequency radio frequency of 13.56MHz and a high-frequency radio frequency power of 10W-50W. The range of chamber pressure when depositing the first SiO2 film can be controlled within the range of 400mT-1200mT. The thickness of the first SiO2 film can be

[0053] S120, depositing a second SiO2 film on the surface of the first SiO2 film using a second PECVD process in situ.

[0054] After depositing the first SiO2 film on the P-type semiconductor layer 40, a second SiO2 film is deposited in situ on the surface of the first SiO2 film using a second PECVD process with a high-frequency (HF) and low-frequency (LF) dual-frequency. Specifically, the second PECVD process uses a high-frequency and low-frequency RF power, and the high-frequency RF power used in the second PECVD process is higher than that in the first PECVD process.

[0055] The high-frequency part in the second PECVD process can obtain a higher density plasma to improve the deposition efficiency and thickness uniformity of the second SiO2 film. The low-frequency part can enhance the bombardment of the first SiO2 film and the second SiO2 film, improve the density of the film, and the first SiO2 film can serve as a protective layer to prevent the high-energy particles generated by the low-frequency part from directly bombarding the P-type semiconductor layer and causing damage.

[0056] The current blocking layer manufactured in this embodiment not only has high insulation and compactness, but also can avoid causing damage to the P-type semiconductor layer.

[0057] In some embodiments, the second PECVD process uses reactant gases including SiH4, N2O, and N2. A high-frequency-low-frequency dual-frequency second PECVD process is used in situ to deposit a second SiO2 film on the surface of the first SiO2 film using SiH4, N2O, and N2 as reactant gases.

[0058] In some embodiments, in the second PECVD process, the high-frequency RF power is 200W-700W, and the high-frequency RF frequency is 10MHz-60MHz.

[0059] In the dual-frequency process, the high-frequency part can obtain a higher density plasma to improve the deposition efficiency and thickness uniformity of the second SiO2 film. As an example, the high-frequency RF frequency can be a commonly used RF frequency of 13.56 MHz. However, the SiO2 film formed only by high frequency has poor density, which will affect the insulation of the SiO2 film. To solve this problem, in some embodiments, in the second PECVD process, the low-frequency RF power is 80W-300W, and the low-frequency RF frequency is 100KHz-500KHz. The low-frequency part of this embodiment can enhance the bombardment of the first SiO2 film and the second SiO2 film, improve the density of the film, and the improvement of the density also enhances the insulation of the film; and the first SiO2 film can serve as a protective layer to prevent the high-energy particles generated by the low-frequency part from directly bombarding the P-type semiconductor layer and causing damage. For example, the low-frequency RF power and RF frequency can be 80-300W and 100-500KHz, respectively.

[0060] In one embodiment, in the preparation step of the second SiO2 film (i.e., the second PECVD process), the flow rate of SiH4 can be 10sccm-60sccm, the flow rate of N2O can be 1000sccm-3000sccm, and the flow rate of N2 can be 900sccm-2800sccm. As an example, using SiH4, N2O and N2 with the above flow rates as reaction gases, the deposition reaction is carried out under the conditions that the high-frequency RF power and RF frequency are 200W-700W, 10MHz-60MHz, and the low-frequency RF power and low-frequency RF frequency are 80W-300W, 100KHz-500KHz respectively. The range of chamber pressure when depositing the second SiO2 film can be controlled within the range of 600mT-1200mT. The thickness of the second SiO2 film can be

[0061] As described above, the preparation method of the current blocking layer provided in this embodiment divides the entire current blocking layer into two layers (a first SiO2 film and a second SiO2 film) for preparation, and two PECVD processes are performed. First, the first PECVD process uses high-frequency RF power, and the high-frequency RF power used in the first PECVD process is lower than that in the second PECVD process, that is, the first SiO2 film is prepared by the first PECVD process with low RF power and high RF frequency (HF), which can avoid the high-energy particles generated by the traditional low RF frequency (LF) preparation process from damaging the surface of the P-type semiconductor layer. Then, the second PECVD process is used. The VD process uses a high-frequency and low-frequency dual-frequency RF power, and uses a higher high-frequency RF power than the first PECVD process. That is, the second PECVD process uses a high-frequency and low-frequency dual-frequency in situ to deposit the second SiO2 film on the surface of the first SiO2 film. The high-frequency portion can obtain a higher density plasma to improve the deposition efficiency and thickness uniformity of the second SiO2 film. The low-frequency portion can enhance the bombardment of the first and second SiO2 films, improving the density of the films. The first SiO2 film can also serve as a protective layer to prevent the high-energy particles generated by the low-frequency portion from directly bombarding the P-type semiconductor layer and causing damage. The current blocking layer produced in this embodiment not only has high insulation and density, but also can avoid damage to the P-type semiconductor layer.

[0062] It should be noted that the reaction principle of preparing SiO2 thin film using SiH4, N2O and N2 as reaction gases in this embodiment is as follows:

[0063] In SiH4 plasma, SiH4 collides with electrons and decomposes. The reaction equations are as follows: e+SiH4→SiH2+H2+e (1) e+SiH4→SiH3+H+e (2) e+SiH4→Si+2H2+e (3) e+SiH4→SiH+H2+H+e (4)

[0064] In the above reaction equations (1)-(4), the energy required for each ionization reaction is 2.1eV, 4.1eV, 4.4eV and 5.9eV respectively. Due to the difference in reaction energy, the probability of each reaction (1)-(4) occurring is extremely uneven. The reaction with lower energy is easier to react. The reaction is mainly (1) and a small amount of reaction (2). The Si group is very rare. In addition, some high-energy electrons in the plasma may also undergo the following reaction: e+SiH4→SiH2++H2+e (5)

[0065] In addition to the above-mentioned ionization reactions, the secondary reaction between ions and molecules is also important: SiH2++SiH4→SiH3++SiH3 (6)

[0066] Therefore, the concentration of SiH3 neutral active groups is the highest in SiH4 plasma.

[0067] In N2O plasma, N2O collides with electrons to dissociate, and the reaction equations are as follows: e+N2O→NO+N+e (7) e+NO→N+O+e (8)

[0068] The formation of SiO2 is mainly the reaction of O active groups with SiH2 and SiH3 groups. The reaction formula is as follows: (SiH3)x+(O)x→SiO2+H2+H2O (9) (SiH2)x+(O)x→SiO2+H2+H2O (10)

[0069] In the PECVD process, most of the plasma in which SiH4, N2O and N2 are used to prepare SiO2 films is composed of SiH2 and SiH3 groups, while there are very few Si groups (especially when SiH4 is excessive). Therefore, almost no Si-N bonds are formed in the SiO2 film deposition reaction. However, there will be some Si-H bonds and Si dangling bonds on the surface of the film, such as reaction equations (3) and (4). This will cause the SiO2 film to be micro-conductive, reducing the insulation of the current blocking layer.

[0070] In order to further improve the insulation of the current blocking layer, please refer to Figure 3, which is a flow chart of a method for preparing a current blocking layer provided in another embodiment of the present application. The method for preparing the current blocking layer may further include step S111 and / or step S121.

[0071] For example, in one embodiment, after step S110 , step S111 may be included to perform surface treatment on the first SiO 2 film.

[0072] S111, introducing a surface treatment gas in situ and igniting to form plasma, performing surface treatment on the first SiO2 film to reduce the surface conductivity of the first SiO2 film.

[0073] It should be noted that the surface treatment gas is mainly used to break Si-H bonds and combine with Si dangling bonds to eliminate micro-conductivity on the surface of the first SiO2 film.

[0074] For example, the surface treatment gas can be N2O. After the first SiO2 film is deposited, N2O is introduced in situ for ignition treatment. The N atoms introduced during N2O ignition can break the Si-H bonds and eliminate Si dangling bonds, thereby improving the insulation properties of the first SiO2 film.

[0075] However, in the above embodiment, N atoms combine with the dangling bonds of Si to form Si-N bonds. The presence of Si-N bonds increases the light absorption of the first SiO2 film, thereby reducing the light extraction efficiency of the LED chip.

[0076] Therefore, the preferred surface treatment gases are He and O2. He and O2 ignite to form He and O ions. The He ions bombard the film surface, breaking Si-H bonds. The O ions can then combine with Si dangling bonds and, in turn, combine with H ions and their active species to form byproducts that are then extracted from the chamber. Furthermore, due to the light molecular weight of He atoms, they cause minimal damage to the SiO2 film surface.

[0077] In one embodiment, during the surface treatment process, the RF power for ignition after in-situ introduction of He and O₂ is 100 W to 500 W, and the RF frequency is 13.56 MHz. The He flow rate can be 5000 sccm to 8000 sccm, and the ratio of He flow rate to O₂ flow rate is 2000:1 to 5000:1. The O₂ flow rate is relatively low because O ions are highly reactive and can easily damage the SiO₂ film, so it should not be too high.

[0078] In one embodiment, when He and O2 are introduced in situ for surface treatment, the chamber pressure is preferably set to 800mT-1500mT. Maintaining a low chamber pressure is conducive to He ions breaking Si-H bonds on the surface of the SiO2 film.

[0079] For example, in another embodiment, after step S120, step S121 may be included to perform surface treatment on the second SiO2 film.

[0080] S121. Introduce surface treatment gas in situ and ignite to form plasma, and perform surface treatment on the second SiO2 film to reduce the surface conductivity of the second SiO2 film.

[0081] The specific implementation of S121 can refer to the implementation of S111, which will not be repeated here.

[0082] Please refer to Figures 1 and 4. Figure 4 is a schematic diagram of a preferred method for preparing a current blocking layer provided in an embodiment of the present application. The preparation method may include steps S110 and S120, and after completing step S110, step S111 is first performed to surface treat the first SiO2 film, then step S120 is performed, and finally step S121 is performed to surface treat the second SiO2 film. By surface treating the first SiO2 film and the second SiO2 film respectively, the micro-conductivity on the surface of the SiO2 film can be eliminated, and the insulation of the current blocking layer can be further improved. In addition, the surface treatment gas is selected from He and O2 to avoid the problem that N2O will combine with Si dangling bonds to form Si-N, resulting in low light extraction efficiency.

[0083] According to the production process of the embodiment of Figure 4, a current blocking layer was prepared using N2O as the surface treatment gas (control example), and a current blocking layer was prepared using He and O2 as the surface treatment gas (example). The performance of the two current blocking layers was tested, and the test results are shown in Table 1.

[0084] Table 1, Performance test results of the current blocking layers prepared in the control example and the embodiment

[0085] The principle of the electrical performance test is: since the current blocking layer exists between the conductive layer and the P-type semiconductor layer, the existence of the current blocking layer reduces the ohmic contact area between the conductive layer and the P-type semiconductor layer, so that the current blocking layer is equivalent to a series resistor in the transmission path. Therefore, when the test current is constant, the increase in the operating voltage can indicate the improvement of the insulation performance of the current blocking layer.

[0086] It can be seen from the test data in Table 1 that the insulation and light extraction efficiency of the current blocking layer of the embodiment are better than those of the current blocking layer of the control example.

[0087] An embodiment of the present application also provides an LED chip, please refer to Figure 1, the LED chip includes a substrate 10 and an N-type semiconductor layer 20, a multi-quantum well layer 30, a P-type semiconductor layer 40, a conductive layer 50, a P-electrode 60 connected to the conductive layer 50, and an N-electrode 70 connected to the N-type semiconductor layer 20, which are arranged in sequence on the substrate 10 along a direction away from the substrate 10 (i.e., from bottom to top). A current blocking layer 80 is provided in the area between the P-type semiconductor layer 40 and the conductive layer 50 facing the P-electrode 60, and the current blocking layer 80 is prepared using the preparation method described in any of the above embodiments.

[0088] For other working principles and processes of the LED chip of this embodiment, please refer to the description of the preparation method of the current blocking layer in the aforementioned embodiment of the present invention, which will not be repeated here.

[0089] In summary, the preparation method of the current blocking layer of the present application is to divide the entire current blocking layer into two layers (a first SiO2 film and a second SiO2 film) for production, and to perform two PECVD processes. First, the first PECVD process uses high-frequency RF power, and the high-frequency RF power used in the first PECVD process is lower than that in the second PECVD process, that is, the first SiO2 film is prepared by the first PECVD process with low RF power and high RF frequency (HF), which can avoid the high-energy particles generated by the traditional low RF frequency (LF) preparation process from damaging the surface of the P-type semiconductor layer. Then, the second PECVD process is used. The D process uses a high-frequency and low-frequency dual-frequency RF power, and uses a higher high-frequency RF power than the first PECVD process. That is, the second PECVD process using a high-frequency and low-frequency dual-frequency in situ is used to deposit the second SiO2 film on the surface of the first SiO2 film. The high-frequency portion can obtain a higher density plasma to improve the deposition efficiency and thickness uniformity of the second SiO2 film. The low-frequency portion can enhance the bombardment of the first and second SiO2 films, improving the density of the films. The first SiO2 film can also serve as a protective layer to prevent the high-energy particles generated by the low-frequency portion from directly bombarding the P-type semiconductor layer and causing damage. The current blocking layer produced in this embodiment not only has high insulation and density, but also avoids damage to the P-type semiconductor layer. Furthermore, the present application can also perform surface treatment on the first and second SiO2 films separately to improve the insulation of the current blocking layer. Furthermore, by using He and O2 as surface treatment gases, the present application can improve the insulation of the current blocking layer while not reducing the light extraction efficiency of the current blocking layer.

[0090] The above describes in detail the method for preparing a current blocking layer and the LED chip provided by this application. This article uses specific examples to illustrate the principles and implementation methods of this application. It should be noted that the descriptions of each embodiment in this application have their own emphases. For portions not detailed or described in one embodiment, please refer to the relevant descriptions of other embodiments.

[0091] The above are only preferred embodiments of the present application and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for preparing a current blocking layer, characterized in that: include: forming a first SiO2 film on a substrate by using a first PECVD process; In-situ depositing a second SiO2 film on the surface of the first SiO2 film using a second PECVD process; Among them, the first PECVD process adopts high-frequency RF power, the second PECVD process adopts high-frequency-low-frequency dual-frequency RF power, and the high-frequency RF power adopted by the first PECVD process is lower than the high-frequency RF power adopted by the second PECVD process.

2. The preparation method according to claim 1, characterized in that: In the first PECVD process, the high-frequency RF power is 10W-50W, and the high-frequency RF frequency is 10MHz-60MHz.

3. The preparation method according to claim 1, characterized in that: In the second PECVD process, the high-frequency RF power is 200W-700W, and the high-frequency RF frequency is 10MHz-60MHz.

4. The preparation method according to claim 1, characterized in that: In the second PECVD process, the low-frequency RF power is 80W-300W, and the low-frequency RF frequency is 100KHz-500KHz.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The reaction gases used in the first PECVD process and the second PECVD process include SiH4, N2O and N2.

6. The preparation method according to claim 1, characterized in that: After depositing a second SiO2 film on the surface of the first SiO2 film by a second PECVD process in situ, the method further includes: The surface treatment gas is introduced in situ and ignited to form plasma, and the second SiO2 film is treated Surface treatment is performed to reduce the conductivity of the surface of the second SiO2 film.

7. The preparation method according to claim 1, characterized in that: After the first SiO2 film is formed on the substrate by the first PECVD process, the method further comprises: A surface treatment gas is introduced in situ and ignited to form plasma, so as to perform surface treatment on the first SiO2 film to reduce the conductivity of the surface of the first SiO2 film.

8. The preparation method according to claim 6 or 7, characterized in that: The surface treatment gas includes He and O2.

9. The preparation method according to claim 8, characterized in that: In the surface treatment process, the ignition radio frequency power is 100W-500W, and the radio frequency is 13.56MHz.

10. The preparation method according to claim 9, characterized in that: The flow rate of He is 5000sccm-8000sccm, and the ratio of the flow rate of He to the flow rate of O2 is 2000:1-5000:

1.

11. The preparation method according to claim 10, characterized in that: In the surface treatment process, the chamber pressure is 800mT-1500mT.

12. The preparation method according to claim 5, characterized in that: In the first PECVD process, the flow rate of SiH4 is 5sccm-35sccm, the flow rate of N2O is 500sccm-1700sccm, and the flow rate of N2 is 800sccm-2400sccm.

13. The preparation method according to any one of claims 1 to 4, characterized in that: In the first PECVD process, the chamber pressure is 400mT-1200mT.

14. The preparation method according to claim 5, characterized in that: In the second PECVD process, the flow rate of SiH4 is 10sccm-60sccm, the flow rate of N2O is 1000sccm-3000sccm, and the flow rate of N2 is 900sccm-2800sccm.

15. The preparation method according to any one of claims 1 to 4, characterized in that: In the second PECVD process, the chamber pressure is 600mT-1200mT.

16. An LED chip, comprising a substrate and an N-type semiconductor layer, a multi-quantum well layer, a P-type semiconductor layer, a conductive layer, a P-electrode connected to the conductive layer, and an N-electrode connected to the N-type semiconductor layer, which are sequentially arranged on the substrate in a direction away from the substrate, wherein a current blocking layer is arranged in a region between the P-type semiconductor layer and the conductive layer facing the P-electrode, characterized in that: The current blocking layer is prepared by the preparation method according to any one of claims 1 to 15.

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