Preparation method of current blocking layer and LED chip

Abstract

The invention discloses a preparation method of a current blocking layer and an LED chip, and the preparation method comprises the steps: taking SiH4, N2O and N2 as reaction gases, employing a first PECVD technology to manufacture a first SiO2 film on a substrate, and in the first PECVD technology, the radio frequency power is 10-50 W, and the radio frequency is 10-60 MHz; siH4, N2O and N2 are taken as reaction gases, a second SiO2 film is deposited on the surface of the first SiO2 film in situ by adopting a high-frequency-low-frequency double-frequency second PECVD (plasma enhanced chemical vapor deposition) process, the radio-frequency power and the radio-frequency frequency of the high frequency are 200-700W and 10-60MHz respectively, and the radio-frequency power and the radio-frequency frequency of the low frequency are 80-300W and 100-500KHz respectively. The current blocking layer manufactured by the invention has relatively high insulativity and compactness, and damage to the P-type semiconductor layer can be avoided.

Description

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] The structural diagram of an existing LED chip is as follows: Figure 1 As shown, from bottom to top, it includes a substrate 10, an N-type semiconductor layer 20, a multiple quantum well layer 30 (Multiple Quantum Well, 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 in the area between the P-type semiconductor layer 40 and the conductive layer 50 facing the P-electrode 60.

[0003] The P-type carriers and the N-type carriers are recombined 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 film, which can prevent the current generated from the P electrode 60 from diffusing toward the conductive layer 50 in the area directly below, increase the current density in other areas of the conductive layer 50, thereby reducing the absorption of the light by the P electrode 60, better extracting photons from the LED chip, and improving the distribution of the current 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 higher dielectric constant (insulation) and higher density.

[0004] Currently, SiO2 films are mainly produced using the PECVD process and deposited under high RF power and low RF frequency. Although this can improve the insulation and density of the SiO2 film, it will damage the epitaxial P-type semiconductor layer 40. In order to avoid damage to the epitaxial 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 decrease. Summary of the invention

[0005] 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 making 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.

[0006] In order 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:

[0007] Using SiH4, N2O and N2 as reaction gases, a first PECVD process is used to form a first SiO2 film on a substrate, wherein in the first PECVD process, the radio frequency power is 10-50W and the radio frequency frequency is 10-60MHz;

[0008] Using SiH4, N2O and N2 as reaction gases, a second SiO2 film is deposited on the surface of the first SiO2 film by an in-situ high-frequency-low-frequency dual-frequency second PECVD process, wherein in the second PECVD process, the high-frequency RF power is 200-700W, the high-frequency RF frequency is 10-60MHz, the low-frequency RF power is 80-300W, and the low-frequency RF frequency is 100-500KHz.

[0009] Optionally, after depositing a second SiO2 film on the surface of the first SiO2 film by the in-situ high-frequency-low-frequency dual-frequency second PECVD process, the method further comprises:

[0010] 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.

[0011] Optionally, after the first SiO2 film is formed on the substrate by the first PECVD process, the method further includes:

[0012] 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.

[0013] Optionally, the surface treatment gas includes He and O2.

[0014] Optionally, in the surface treatment process, the RF power of the ignition is 100-500W, and the RF frequency is 13.56MHz.

[0015] Optionally, the flow rate of He is 5000-8000 sccm, and the ratio of the flow rate of He to the flow rate of O2 is 2000:1-5000:1.

[0016] Optionally, in the surface treatment process, the chamber pressure is 800-1500mT.

[0017] Optionally, in the step of preparing the first SiO2 film, the flow rate of SiH4 is 5-35 sccm, the flow rate of N2O is 500-1700 sccm, and the flow rate of N2 is 800-2400 sccm.

[0018] Optionally, in the step of preparing the first SiO2 film, the chamber pressure is 400-1200 mT.

[0019] Optionally, in the step of preparing the second SiO2 film, the flow rate of SiH4 is 10-60sccm, the flow rate of N2O is 1000-3000sccm, and the flow rate of N2 is 900-2800sccm.

[0020] Optionally, in the step of preparing the second SiO2 film, the chamber pressure is 600-1200mT.

[0021] In the second aspect, an embodiment of the present application provides an LED chip, comprising, from bottom to top, a substrate, 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, a current blocking layer is provided in a region between the P-type semiconductor layer and the conductive layer facing the P electrode, and the current blocking layer is characterized in that the current blocking layer is prepared by the preparation method described in the above embodiments.

[0022] As described above, 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 preparation. Through two PECVD processes, the first SiO2 film is first prepared by a 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 SiO2 film is deposited on the surface of the first SiO2 film in situ by a second PECVD process with high-frequency-low-frequency dual frequency. The high-frequency part 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 compactness of the film, and the first SiO2 film can be used 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. The current blocking layer prepared in this embodiment not only has high insulation and compactness, but also can avoid damage to the P-type semiconductor layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present application, and are used together with the specification 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 drawings required for use in the description of the embodiments are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor.

[0024] Figure 1 It is a structural schematic diagram of an existing LED chip;

[0025] Figure 2 It is a schematic flow chart of a method for preparing a current blocking layer provided by an embodiment of the present application;

[0026] Figure 3 is a schematic flow chart of a method for preparing a current blocking layer provided in another embodiment of the present application;

[0027] Figure 4 It is a schematic diagram of a preferred method for preparing a current blocking layer provided in an embodiment of the present application.

[0028] The realization of the purpose, functional features and advantages of this application will be further described in conjunction with the embodiments and with reference to the accompanying drawings. The above-mentioned drawings have shown clear embodiments of this application, which will be described in more detail later. These drawings and textual descriptions are not intended to limit the scope of the concept of this application in any way, but to illustrate the concept of this application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0029] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0030] It should be noted that, in this article, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes 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 "includes a ..." does not exclude the existence of other identical elements in the process, method, article or device including 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.

[0031] 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.

[0032] 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 only used to distinguish information of the same type from each other. For example, without departing from the scope of this document, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, as used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless otherwise indicated in the context.

[0033] It should be understood that the orientations or positional relationships indicated by terms such as "top", "bottom", "up", "down", "vertical", and "horizontal" 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. They 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 should not be understood as a limitation on the present application.

[0034] Before preparing the current blocking layer of this embodiment, a light-emitting functional layer may be formed on the surface of the substrate.

[0035] In some optional embodiments, the substrate 10 may be sapphire, silicon carbide, silicon, a silicon-containing substrate, an epitaxial silicon substrate, silicon on insulator (SOI), lithium niobate, diamond or other materials.

[0036] 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 sequentially formed on the surface of the substrate 10. The P-type carriers in the P-type semiconductor layer 40 and the N-type carriers in the N-type semiconductor layer 20 are recombined 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.

[0037] 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.

[0038] See also Figure 2 , Figure 2 It is a schematic flow chart of a method for preparing a current blocking layer provided in an embodiment of the present application. The preparation method may include S110-S120.

[0039] S110, using SiH4, N2O and N2 as reaction gases, adopting a first PECVD process to form a first SiO2 film on the substrate, wherein in the first PECVD process, the RF power is 10-50W, and the RF frequency is 10-60MHz.

[0040] Plasma Enhance Chemical Vapour Deposition (PECVD) is a process that uses plasma formed by glow discharge to influence the deposition process during low-pressure chemical vapor deposition to prepare a thin film on a substrate.

[0041] In this embodiment, SiH4, N2O and N2 are used as reaction gases, wherein N2 is used as a diluent gas, and the Si source provided by SiH4 and the O source provided by N2O react to generate SiO2, and the first SiO2 film can be formed on the local area of ​​the top surface of the P-type semiconductor layer of the substrate. As mentioned above, when the SiO2 film is made by the traditional PECVD process, high RF power and low RF frequency will cause damage to the P-type semiconductor layer 40. This is because the plasma density excited by the low RF frequency power supply is low, the free path of the particles is long, the collision probability between the particles is small, and the bombardment energy of the particles on the P-type semiconductor layer 40 is large, thereby causing damage to the surface of the P-type semiconductor layer.

[0042] In the first PECVD process of this embodiment, low RF power and high RF frequency (HF) are used to form the first SiO2 film, which can avoid ion bombardment from causing damage to the surface of the P-type semiconductor layer. For example, the RF power can be 10-50W, and the RF frequency can be 10-60MHz. For example, HF can use a commonly used RF frequency of 13.56MHz.

[0043] In one embodiment, in the preparation step of the first SiO2 film, the flow rate of SiH4 can be 5-35sccm, the flow rate of N2O can be 500-1700sccm, and the flow rate of N2 can be 800-2400sccm. As an example, the chamber background vacuum can be evacuated to 3-5mT first, and the deposition temperature range of the SiO2 film can be set to 100℃-200℃. SiH4, N2O and N2 with the above flow rates are used as reaction gases, and the deposition reaction is carried out under the conditions of a high frequency of 13.56MHz and a radio frequency power of 10-50W. When depositing the first SiO2 film, the chamber pressure range of the chamber can be controlled within the range of 400-1200mT. The thickness of the first SiO2 film can be

[0044] S120. Using SiH4, N2O and N2 as reaction gases, a second SiO2 film is deposited on the surface of the first SiO2 film by an in-situ high-frequency-low-frequency dual-frequency second PECVD process. In the second PECVD process, the high-frequency RF power is 200-700W, the high-frequency RF frequency is 10-60MHz, the low-frequency RF power is 80-300W, and the low-frequency RF frequency is 100-500KHz.

[0045] After the first layer of SiO2 film is deposited on the P-type semiconductor layer 40, a second PECVD process of high frequency (HF)-low frequency (LF) dual frequency is used in situ to deposit a second SiO2 film on the surface of the first SiO2 film. 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. For example, the radio frequency power and radio frequency of the high frequency can be 200-700W and 10-60MHz, respectively. As an example, the frequency of the high frequency can be a commonly used radio frequency frequency of 13.56MHz. However, the SiO2 film formed only by high frequency has poor density, which will affect the insulation of the SiO2 film. 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 be used 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.

[0046] In one embodiment, in the preparation step of the second SiO2 film, the flow rate of SiH4 can be 10-60sccm, the flow rate of N2O can be 1000-3000sccm, and the flow rate of N2 can be 900-2800sccm. As an example, with the above-mentioned flow rates of SiH4, N2O and N2 as reaction gases, the deposition reaction is carried out under the conditions that the high-frequency RF power and RF frequency are 200-700W and 10-60MHz respectively, and the low-frequency RF power and RF frequency are 80-300W and 100-500KHz respectively. When depositing the second SiO2 film, the chamber pressure range of the chamber can be controlled within the range of 600-1200mT. The thickness of the second SiO2 film can be

[0047] As described above, the preparation method of the current blocking layer of this embodiment is to divide the entire current blocking layer into two layers (a first SiO2 film and a second SiO2 film) for preparation. Through two PECVD processes, the first SiO2 film is first prepared by a 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 SiO2 film is deposited on the surface of the first SiO2 film by a second PECVD process with high-frequency-low-frequency dual frequency in situ. The high-frequency part 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 compactness of the film, and the first SiO2 film can be used 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. The current blocking layer prepared in this embodiment not only has high insulation and compactness, but also can avoid damage to the P-type semiconductor layer.

[0048] It should be noted that the reaction principle of preparing SiO2 using SiH4, N2O and N2 as reaction gases in this embodiment is as follows:

[0049] In SiH4 plasma, SiH4 collides with electrons to decompose, and the reaction formula is as follows:

[0050] e+ SiH4→SiH2+H2+e (1)

[0051] e+ SiH4→SiH3+H+e (2)

[0052] e+ SiH4→Si+2H2+e (3)

[0053] e+SiH4→SiH+H2+H+e (4)

[0054] In the above reaction formulas (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 low energy is easier to react. The reaction is mainly (1) and a small amount of reaction (2). There is very little Si base. In addition, some high-energy electrons in the plasma may also undergo the following reactions:

[0055] e+SiH4→SiH2 + +H2+e (5)

[0056] In addition to the above-mentioned ionization reactions, secondary reactions between ions and molecules are also important:

[0057] SiH2 + +SiH4→SiH3++SiH3(6)

[0058] Therefore, the concentration of SiH3 neutral active groups is the highest in SiH4 plasma.

[0059] In N2O plasma, N2O collides with electrons to dissociate, and the reaction equation is as follows:

[0060] e+N2O→NO+N+e (7)

[0061] e+NO→N+O+e (8)

[0062] The formation of SiO2 is mainly the reaction of O active groups with SiH2 and SiH3 groups. The reaction formula is as follows:

[0063] (SiH3)x+(O)x→SiO2+H2+H2O (9)

[0064] (SiH2)x+(O)x→SiO2+H2+H2O (10)

[0065] In the plasma used for preparing SiO2 film by PECVD using SiH4 / N2O / N2, most of the groups present are 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.

[0066] To further improve the insulation of the current blocking layer, see Figure 3 , Figure 3is a schematic flow chart of a method for preparing a current blocking layer provided in yet another embodiment of the present application. The method for preparing a current blocking layer may further include S111 and / or S121.

[0067] For example, in one embodiment, after step S110 , step S111 may be included to perform surface treatment on the first SiO 2 film.

[0068] S111, introducing a surface treatment gas in situ and igniting to form plasma, performing surface treatment on the first SiO2 film to reduce the conductivity of the surface of the first SiO2 film.

[0069] It should be noted that the surface treatment gas is mainly used to break the Si-H bonds and combine with the Si dangling bonds to eliminate the microconductivity on the surface of the SiO2 film.

[0070] For example, the surface treatment gas can be N2O. After the first SiO2 film is deposited, N2O is introduced for ignition treatment in situ. The N atoms introduced during N2O ignition can break the Si-H bonds and eliminate Si dangling bonds, thereby improving the insulation of the first SiO2 film.

[0071] However, in the above embodiment, N atoms combine with the dangling bonds of Si to form Si-N bonds. The existence of Si-N bonds will increase the light absorption of the first SiO2 film and reduce the light extraction efficiency of the LED chip.

[0072] Therefore, preferably, the surface treatment gas is He and O2. He and O2 form He ions and O ions after ignition. He ions bombard the film surface, breaking Si-H bonds, and O ions can combine with Si hanging bonds and are used to combine H ions and their active substances to generate byproducts that are extracted from the chamber. At the same time, due to the light molecular weight of He atoms, the surface of the SiO2 film is less damaged.

[0073] In one embodiment, the RF power of the ignition after the in-situ introduction of He and O2 is 100-500W, and the RF frequency is 13.56MHz. The flow rate of He can be 5000-8000sccm, and the ratio of the flow rate of He to the flow rate of O2 is 2000:1-5000:1. The flow rate of O2 is relatively low because the activity of O ions is relatively high and it is easy to damage the SiO2 film, so the flow rate should not be too high.

[0074] In one embodiment, when He and O2 are introduced in situ for surface treatment, the chamber pressure is preferably set to 800-1500 mT. Maintaining a low chamber pressure is conducive to He ions breaking Si-H bonds on the surface of the SiO2 film.

[0075] For example, in another embodiment, after step S120, step S121 may be included to perform surface treatment on the second SiO2 film.

[0076] S121. Introduce a surface treatment gas in situ and ignite to form plasma, and perform surface treatment on the second SiO2 film to reduce the conductivity of the surface of the second SiO2 film.

[0077] The specific implementation of S121 can refer to the implementation of S111, which will not be described in detail here.

[0078] See also Figure 1 and Figure 4 , Figure 4 It 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 S110-S120, and after completing step S110, step S111 is first performed to perform surface treatment on the first SiO2 film, then step S120 is performed, and finally step S121 is performed to perform surface treatment on the second SiO2 film. By performing surface treatment on 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, which can avoid the problem that N2O will combine with Si hanging bonds to form Si-N, resulting in low light extraction efficiency.

[0079] according to Figure 4 The production process of the embodiment is to prepare a current blocking layer using N2O as the surface treatment gas (control example), and to prepare a current blocking layer using He and O2 as the surface treatment gas (embodiment). The performance of the two current blocking layers is tested, and the test results are shown in Table 1.

[0080] Table 1 Performance test results of the current blocking layer prepared in the control example and the embodiment

[0081] sample Working voltage(V) Light output efficiency (ml / W) Comparison Example 2.974 95.83 Example 3.213 110.26

[0082] 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.

[0083] 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.

[0084] The present application also provides an LED chip. Figure 1The LED chip includes, from bottom to top, a substrate 10, 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. A current blocking layer 80 is provided in a region between the P-type semiconductor layer 40 and the conductive layer 50 facing the P-electrode 60. The current blocking layer 80 is prepared by the preparation method described in any of the above embodiments.

[0085] 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.

[0086] In summary, the preparation method of the current blocking layer of the present application divides the entire current blocking layer into two layers (a first SiO2 film and a second SiO2 film) for preparation. Through two PECVD processes, the first SiO2 film is first prepared by a 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 SiO2 film is deposited on the surface of the first SiO2 film by a second PECVD process with high-frequency-low-frequency dual frequency in situ. The high-frequency part 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 compactness of the film, and the first SiO2 film can be used 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. The current blocking layer prepared in this embodiment not only has high insulation and compactness, but also can avoid damage to the P-type semiconductor layer. Furthermore, the present application can also perform surface treatment on the first SiO2 film and the second SiO2 film respectively to improve the insulation of the current blocking layer. Furthermore, the present application can improve the insulation of the current blocking layer without reducing the light extraction efficiency of the current blocking layer by using He and O2 as surface treatment gases.

[0087] The above is a detailed introduction to a method for preparing a current blocking layer and an LED chip provided by the present application. This article uses specific examples to illustrate the principle and implementation of the present application. It should be noted that in the present application, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0088] The above are only preferred embodiments of the present application, and are not intended to 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: Using SiH4, N2O and N2 as reaction gases, a first PECVD process is used to form a first SiO2 film on a substrate, wherein in the first PECVD process, the radio frequency power is 10-50W and the radio frequency frequency is 10-60MHz; Using SiH4, N2O and N2 as reaction gases, a second SiO2 film is deposited on the surface of the first SiO2 film by an in-situ high-frequency-low-frequency dual-frequency second PECVD process, wherein in the second PECVD process, the high-frequency RF power is 200-700W, the high-frequency RF frequency is 10-60MHz, the low-frequency RF power is 80-300W, and the low-frequency RF frequency is 100-500KHz.

2. The preparation method according to claim 1, characterized in that: After depositing the second SiO2 film on the surface of the first SiO2 film by the in-situ high-frequency-low-frequency dual-frequency second PECVD process, the method further includes: 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.

3. 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.

4. The preparation method according to claim 2 or 3, characterized in that: The surface treatment gas includes He and O2.

5. The preparation method according to claim 4, characterized in that: In the surface treatment process, the ignition radio frequency power is 100-500W, and the radio frequency is 13.56MHz.

6. The preparation method according to claim 5, characterized in that: The flow rate of He is 5000-8000 sccm, and the ratio of the flow rate of He to the flow rate of O2 is 2000:1-5000:

1.

7. The preparation method according to claim 6, characterized in that: In the surface treatment process, the chamber pressure is 800-1500mT.

8. The preparation method according to any one of claims 1 to 3, characterized in that: In the step of preparing the first SiO2 film, the flow rate of SiH4 is 5-35 sccm, the flow rate of N2O is 500-1700 sccm, and the flow rate of N2 is 800-2400 sccm.

9. The preparation method according to claim 8, characterized in that: In the step of preparing the first SiO2 film, the chamber pressure is 400-1200 mT.

10. The preparation method according to claim 8, characterized in that: In the step of preparing the second SiO2 film, the flow rate of SiH4 is 10-60sccm, the flow rate of N2O is 1000-3000sccm, and the flow rate of N2 is 900-2800sccm.

11. The preparation method according to claim 10, characterized in that: In the step of preparing the second SiO2 film, the chamber pressure is 600-1200 mT.

12. An LED chip, comprising, from bottom to top, a substrate, 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, wherein a current blocking layer is provided 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 11.

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