Schottky diode for radio frequency energy transmission system and preparation method thereof

Abstract

The invention provides a Schottky diode for a radio frequency energy transmission system and a preparation method of the Schottky diode, and relates to the technical field of Schottky barrier diodes. Comprising an anode metal electrode and a cathode metal electrode which are arranged on the left side and the right side of the multi-layer structure respectively, the anode metal electrode and the cathode metal electrode are electrically connected with the buffer layer and the layer structure on the buffer layer respectively according to a preset equivalent circuit, and the upper end of the anode metal electrode and the upper end of the cathode metal electrode are buckled on the upper surface of the second barrier layer. And an intercalation layer is arranged between the anode metal electrode and the second barrier layer as an interlayer. The Schottky diode aims to solve the problems of complex process, long tape-out period, high production cost, high process difficulty and the like in the existing preparation process, reverse electric leakage is remarkably reduced, the preparation process is simplified, and the performance and preparation efficiency of the device are improved.

Description

Technical Field

[0001] This invention relates to the field of Schottky barrier diode technology, and more specifically, to a Schottky diode for radio frequency power transmission systems and its fabrication method. Background Technology

[0002] In existing dual-channel Schottky barrier diodes, a MOS structure is typically formed by depositing a gate dielectric (P-GaN) in the channel during the tape-out process to suppress reverse leakage. Therefore, the multilayer structure in existing dual-channel Schottky barrier diodes is generally stacked in a stepped shape, which makes the tape-out process complex. Furthermore, P-GaN needs to be processed separately, so multiple etching steps are often required, resulting in a long tape-out cycle and high production cost. At the same time, P-GaN also needs to be doped with Mg and activated at high temperature, which makes the overall process more difficult.

[0003] There is currently no effective technical solution to the above problems. Summary of the Invention

[0004] The purpose of this invention is to provide a Schottky diode for radio frequency power transmission systems and its fabrication method, aiming to solve the problems of complex processes, long tape-out cycles, high production costs, and high process difficulty faced by existing dual-channel Schottky barrier diodes in the fabrication process, significantly reducing reverse leakage current and simplifying the fabrication process, thereby improving device performance and fabrication efficiency.

[0005] In a first aspect, the present invention provides a Schottky diode for a radio frequency power transmission system, comprising a multilayer structure, wherein the multilayer structure comprises a substrate, a nucleation layer, a buffer layer, a first channel layer, a first barrier layer, a second channel layer, a second barrier layer, and a passivation layer stacked sequentially, and further comprising an anode metal electrode and a cathode metal electrode respectively disposed on the left and right sides of the multilayer structure, wherein the anode metal electrode and the cathode metal electrode are electrically connected to the buffer layer and the layer structure above it according to a preset equivalent circuit, and the upper ends of the anode metal electrode and the cathode metal electrode are fastened to the upper surface of the second barrier layer, and an intercalation layer is further disposed between the anode metal electrode and the second barrier layer as a sandwich layer.

[0006] The Schottky diode for radio frequency power transmission systems provided by this invention optimizes the structure through intercalation design, simplifying the fabrication process and minimizing factors that may degrade yield and device performance during fabrication, thereby further improving device yield.

[0007] Furthermore, the equivalent circuit includes a field-effect transistor composed of the intercalation layer and the second barrier layer, a first Schottky diode composed of the first barrier layer, the second channel layer and the second barrier layer, and a second Schottky diode composed of the buffer layer, the first channel layer and the first barrier layer. The anode metal electrode serves as the anode and is simultaneously connected to the gate of the field-effect transistor, the source of the field-effect transistor, and the positive terminal of the second Schottky diode; the drain of the field-effect transistor is connected to the positive terminal of the first Schottky diode; and the cathode metal electrode serves as the cathode and is simultaneously connected to the negative terminal of both the first and second Schottky diodes.

[0008] By precisely controlling the electrical behavior of each component, especially the effective suppression of electric fields by the field-effect transistor under reverse bias, the reverse blocking capability and reliability of the device are significantly improved, making it a promising candidate for application in low-loss and high-power radio frequency energy transmission systems.

[0009] Furthermore, the intercalation layer is made of AlTiO material.

[0010] Furthermore, the buffer layer, the first channel layer, and the second channel layer are all made of GaN material.

[0011] Furthermore, the thickness of the buffer layer is 2–3 µm; the thickness of the first channel layer is 40–60 nm; and the thickness of the second channel layer is 30–45 nm.

[0012] Furthermore, both the first barrier layer and the second barrier layer are made of AlGaN material.

[0013] Furthermore, the thickness of both the first barrier layer and the second barrier layer is 20–30 nm.

[0014] Furthermore, the thickness of the nucleation layer is 200–300 nm.

[0015] Furthermore, the passivation layer is made of SiN material.

[0016] Secondly, the present invention provides a method for fabricating the aforementioned Schottky diode for a radio frequency power transmission system, comprising the following steps: S1. Using a metal-organic chemical vapor deposition method, the nucleation layer, the buffer layer, the first channel layer, the first barrier layer, the second channel layer, and the second barrier layer are sequentially grown on the substrate; S2. Using photolithography, mark the groove regions of the anode metal electrode and the cathode metal electrode on the multilayer structure; S3. Using the ICP dry etching method, the multilayer structure is etched downwards along the groove region to obtain the anode groove of the anode metal electrode and the cathode groove of the cathode metal electrode; S4. The cathode groove is acid-washed with hydrochloric acid to remove surface oxides. Then, based on the cathode groove, the cathode preparation area of ​​the cathode metal electrode is marked by photolithography. Then, metal is deposited in the cathode preparation area by electron beam evaporation. After the metal is deposited, the deposited metal is annealed in an inert gas atmosphere to obtain a cathode ohmic contact metal electrode as the cathode metal electrode. S5. Deposit the intercalation layer on the upper surface of the second barrier layer; S6. Based on the anode groove, after marking the anode preparation area of ​​the anode metal electrode using photolithography, metal is deposited in the anode preparation area using electron beam evaporation to obtain an anode Schottky metal electrode as the anode metal electrode; the anode metal electrode is partially deposited above the intercalation layer so that the intercalation layer serves as an interlayer between the anode metal electrode and the second barrier layer; S7. The passivation layer is deposited using the PECVD method, and the passivation layer is etched using the ICP dry etching method to expose the cathode metal electrode and the anode metal electrode.

[0017] The preparation method of the present invention enables low-cost and high-efficiency manufacturing of dual-channel Schottky barrier diodes.

[0018] As can be seen from the above, the Schottky diode for radio frequency power transmission systems provided by this invention uses an intercalation layer as a sandwich between the anode metal electrode and the second barrier layer. This intercalation layer has performance similar to P-GaN, effectively clamping the lower channel and thus significantly reducing reverse leakage current. Compared to the complex processes required for P-GaN in the prior art, which involve separate processing, designing multiple etching steps, magnesium doping, and high-temperature activation, the intercalation layer in this application only needs to be deposited during the wafer fabrication process, without additional doping and high-temperature activation. This greatly simplifies the wafer fabrication process, shortens the wafer fabrication cycle, and significantly reduces production costs and process difficulty. Therefore, this application effectively solves the problems of complex processes, long wafer fabrication cycles, high production costs, and high process difficulty faced by existing dual-channel Schottky barrier diodes during fabrication, providing a more economical and efficient solution.

[0019] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing embodiments of the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a Schottky diode for a radio frequency power transmission system provided in an embodiment of the present invention.

[0021] Figure 2 This is a preset equivalent circuit diagram in the embodiments of the present invention.

[0022] Figure 3 This is a flowchart of a preparation method provided in an embodiment of the present invention.

[0023] Label Explanation: 1. Substrate; 2. Nucleation layer; 3. Buffer layer; 4. First channel layer; 5. First barrier layer; 6. Second channel layer; 7. Second barrier layer; 8. Passivation layer; 9. Anode metal electrode; 10. Cathode metal electrode; 11. Intercalation layer; 12. First part; 13. Second part; 14. Field-effect transistor; 15. First Schottky diode; 16. Second Schottky diode; 17. Anode; 18. Cathode. Detailed Implementation

[0024] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0025] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element 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 this invention.

[0026] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0027] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0028] The following disclosure provides many different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0030] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Also, in the description of this invention, the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance.

[0031] It should be noted that the terms "up and down" and "left and right" mentioned below are in conjunction with the provided text. Figure 1 The arrows are for reference.

[0032] Reference Appendix Figure 1 This invention provides a Schottky diode for a radio frequency power transmission system, comprising a multilayer structure. The multilayer structure includes a substrate 1, a nucleation layer 2, a buffer layer 3, a first channel layer 4, a first barrier layer 5, a second channel layer 6, a second barrier layer 7, and a passivation layer 8 stacked sequentially. It also includes an anode metal electrode 9 and a cathode metal electrode 10 respectively disposed on the left and right sides of the multilayer structure. Both the anode metal electrode 9 and the cathode metal electrode 10 are electrically connected to the buffer layer 3 and the layer structure above it according to a preset equivalent circuit. The upper ends of both the anode metal electrode 9 and the cathode metal electrode 10 are fastened to the upper surface of the second barrier layer 7. An intercalation layer 11 is further disposed between the anode metal electrode 9 and the second barrier layer 7 as a sandwich layer. Having similar performance to P-GaN, it can effectively clamp the underlying channel, thereby reducing reverse leakage current. In this process, the fabrication process of conventional devices is complex, and P-GaN requires separate processing. However, the intercalation layer 11 only needs to be deposited during the fabrication process, and there is no need for Mg doping and high-temperature activation. Therefore, the fabrication cycle is shorter, the production cost is lower, and the process difficulty is lower. It should be noted that the design of the position of the intercalation layer 11 requires that a part of the anode metal electrode 9 needs to be deposited on top of the intercalation layer 11 so that the intercalation layer 11 exists as a sandwich between the anode metal electrode 9 and the second barrier layer 7. Otherwise, since the anode metal electrode 9 does not contact the intercalation layer 11 to apply voltage, the channel below the intercalation layer 11 will always be in a clamped state, causing the device to fail to conduct.

[0033] The Schottky diode of this application effectively solves the problems of complex processes, long tape-out cycles, high production costs, and high manufacturing difficulty caused by P-GaN gate dielectrics in existing technologies through ingenious structural design. The key lies in the intercalation layer 11 placed between the anode metal electrode 9 and the second barrier layer 7. The intercalation layer 11 has similar performance to P-GaN, and its main function is to effectively suppress reverse leakage by clamping the underlying channel through its electric field effect when a voltage is applied to the anode metal electrode 9. Unlike traditional P-GaN gate dielectrics, the introduction of the intercalation layer 11 does not require magnesium (Mg) doping and high-temperature activation treatment, nor does it require complex multi-stage etching steps. The intercalation layer 11 can be implemented through a simple deposition process during tape-out, such as precise control of its thickness and composition using atomic layer deposition (ALD) technology. This simplified process significantly shortens the tape-out cycle and reduces production costs and manufacturing difficulty.

[0034] During device operation, the anode metal electrode 9 forms an electrical contact with the second barrier layer 7 through the intercalation layer 11. When a forward bias is applied to the anode metal electrode 9, the channel beneath the intercalation layer 11 is opened, allowing current to flow through the first channel layer 4 and the second channel layer 6. When a reverse bias is applied, the pinch-off effect of the intercalation layer 11 effectively suppresses reverse current, thereby reducing leakage current. It is particularly important to emphasize that a portion of the anode metal electrode 9 must be deposited above the intercalation layer 11 to ensure that the intercalation layer 11 can be effectively voltage-applied and perform its pinch-off function. If the anode metal electrode 9 fails to contact the intercalation layer 11, the channel beneath the intercalation layer 11 will remain pinch-off, causing the device to fail to conduct and thus losing its diode function. Therefore, the synergistic effect of the intercalation layer 11 and the anode metal electrode 9 is crucial for achieving low leakage current and normal conduction.

[0035] The Schottky diode proposed in this application demonstrates a significant technological contribution in solving existing technical problems. Traditional dual-channel Schottky barrier diodes typically use P-GaN gate dielectric to suppress reverse leakage, but this leads to complex fabrication processes, requiring separate processing of P-GaN and involving multiple etching steps, thus extending the fabrication cycle and increasing production costs. Furthermore, the preparation of P-GaN also requires magnesium (Mg) doping and high-temperature activation, further increasing the process difficulty.

[0036] In contrast, this application cleverly circumvents the aforementioned problems by introducing an intercalation layer 11 as a sandwich layer. The intercalation layer 11 exhibits performance similar to P-GaN, effectively clamping the underlying channel and reducing reverse leakage. However, unlike P-GaN, the fabrication process of the intercalation layer 11 is significantly simplified. The intercalation layer 11 only needs to be deposited during the wafer fabrication process, for example, using atomic layer deposition (ALD) technology, without the need for magnesium (Mg) doping and high-temperature activation. This simplified process significantly shortens the wafer fabrication cycle and reduces production costs and process complexity.

[0037] Specifically, the Schottky diode of this application achieves effective channel control by placing an intercalation layer 11 between the anode metal electrode 9 and the second barrier layer 7. The introduction of the intercalation layer 11 eliminates the need for the complex stepped structure required for traditional P-GaN devices, thus simplifying the overall fabrication process. For example, during fabrication, instead of performing multiple etching passes to form the P-GaN gate dielectric, the intercalation layer 11 can be deposited directly on the second barrier layer 7, followed by the deposition of a portion of the anode metal electrode 9. This simplification not only improves production efficiency but also reduces the technical requirements for equipment and operators. Therefore, the Schottky diode of this application significantly optimizes the fabrication process while maintaining or even improving electrical performance, providing a new solution for the low-cost, high-efficiency manufacturing of high-performance electronic devices.

[0038] Reference Appendix Figure 2 In some embodiments, the equivalent circuit includes a field-effect transistor 14 (an E-mode HEMT, i.e., an enhancement-mode high electron mobility field-effect transistor, is used instead of a traditional p-GaN HEMT) composed of an intercalation layer 11 and a second barrier layer 7, a first Schottky diode 15 composed of a first barrier layer 5, a second channel layer 6 and a second barrier layer 7, and a second Schottky diode 16 composed of a buffer layer 3, a first channel layer 4 and a first barrier layer 5; In this configuration, the anode metal electrode 9 serves as the anode 17 and is simultaneously connected to the gate of the field-effect transistor 14, the source of the field-effect transistor 14, and the positive terminal of the second Schottky diode 16; the drain of the field-effect transistor 14 is connected to the positive terminal of the first Schottky diode 15; and the cathode metal electrode 10 serves as the cathode 18 and is simultaneously connected to the negative terminal of the first Schottky diode 15 and the negative terminal of the second Schottky diode 16. Its equivalent circuit is formed by a first part 12 and a second part 13 connected in parallel. The first part 12 is equivalent to a first Schottky diode 15 connected in series with a field-effect transistor 14, while the second part 13 is a second Schottky diode 16. The field-effect transistor 14 in the first part 12 is in the off state at zero bias. Therefore, when a forward bias is applied to the anode, if the voltage is greater than the turn-on voltage of the second Schottky diode 16 but less than the threshold voltage of the field-effect transistor 14, the forward conduction current mainly flows out from the second Schottky diode 16. As the anode voltage gradually increases to be greater than the threshold voltage, the field-effect transistor 14 will be in the on state, at which time the first Schottky diode 15 also participates in conduction. Conversely, when a reverse bias is applied to the anode, the field-effect transistor 14 can withstand a portion of the reverse voltage, thereby effectively suppressing the high electric field of the Schottky junction of the first Schottky diode 15 and the second Schottky diode 16. This diode has the characteristics of low leakage current, ultra-high breakdown voltage, and high stability, and has great potential for application in low-loss and high-power radio frequency energy transmission systems.

[0039] Specifically, the construction of the aforementioned equivalent circuit aims to optimize the electrical performance of the Schottky diode. The field-effect transistor 14, composed of intercalation layer 11 and a second barrier layer 7, is designed as an enhancement-mode high electron mobility field-effect transistor (E-mode HEMT) to replace the traditional p-GaN HEMT, thereby simplifying the manufacturing process and reducing costs. The first Schottky diode 15 consists of a first barrier layer 5, a second channel layer 6, and a second barrier layer 7, while the second Schottky diode 16 consists of a buffer layer 3, a first channel layer 4, and a first barrier layer 5. The synergistic effect of these components is key to achieving the superior performance of the device.

[0040] In terms of electrical connections, the anode metal electrode 9, serving as the anode of the device, is designed to be connected simultaneously to the gate of the field-effect transistor 14, the source of the field-effect transistor 14, and the anode of the second Schottky diode 16. This connection ensures that the anode voltage can simultaneously control the switching state of the field-effect transistor 14 and the conduction of the second Schottky diode 16. The drain of the field-effect transistor 14 is connected to the anode of the first Schottky diode 15, allowing current to flow through the first Schottky diode 15 when the field-effect transistor 14 is turned on. The cathode metal electrode 10, serving as the cathode of the device, is connected simultaneously to the cathode of the first Schottky diode 15 and the cathode of the second Schottky diode 16, providing a return path for the current.

[0041] The solution in this application constructs an optimized equivalent circuit by electrically connecting the field-effect transistor 14, the first Schottky diode 15, and the second Schottky diode 16 in a specific manner. Specifically, the field-effect transistor 14 is in the off state at zero bias, ensuring the stability of the device under low voltage. Under forward bias, when the voltage reaches the turn-on voltage of the second Schottky diode 16, current first flows through the second Schottky diode 16, providing the initial conduction path. As the voltage further increases and exceeds the threshold voltage of the field-effect transistor 14, the field-effect transistor 14 is turned on, causing the first Schottky diode 15 to also participate in conduction, thereby achieving dual-channel synergistic conduction and effectively reducing the forward conduction resistance. Under reverse bias, the field-effect transistor 14 can withstand a portion of the reverse voltage, significantly suppressing the high electric field at the Schottky junction of the first Schottky diode 15 and the second Schottky diode 16, thereby effectively reducing reverse leakage current and improving the breakdown voltage of the device.

[0042] Through the above equivalent circuit design, the Schottky diode of this application achieves low leakage current, ultra-high breakdown voltage, and high stability. Compared to devices with only a basic structure, this scheme significantly improves the reverse blocking capability and reliability of the device by precisely controlling the electrical behavior of each component, especially the effective suppression of the electric field by the field-effect transistor 14 under reverse bias, making it highly promising for application in low-loss and high-power radio frequency energy transfer systems.

[0043] In some embodiments, the intercalation layer 11 is made of AlTiO material.

[0044] In some embodiments, the buffer layer 3, the first channel layer 4, and the second channel layer 6 are all made of GaN material.

[0045] Furthermore, buffer layer 3 is made of C-doped GaN material with a doping concentration of 10. 18 cm -3 .

[0046] In some embodiments, the thickness of the buffer layer 3 is 2–3 µm; the thickness of the first channel layer 4 is 40–60 nm; and the thickness of the second channel layer 6 is 30–45 nm.

[0047] In some embodiments, both the first barrier layer 5 and the second barrier layer 7 are made of AlGaN material.

[0048] In some embodiments, the thickness of both the first barrier layer 5 and the second barrier layer 7 is 20-30 nm.

[0049] In some embodiments, the thickness of the nucleation layer 2 is 200–300 nm.

[0050] In some embodiments, the passivation layer 8 is made of SiN material.

[0051] Reference Appendix Figure 3 The present invention provides a method for fabricating a Schottky diode for a radio frequency power transfer system as described in the above embodiments, comprising the following steps: S1. A core layer, a buffer layer, a first channel layer, a first barrier layer, a second channel layer, and a second barrier layer are sequentially grown on a substrate using a metal-organic chemical vapor deposition method. S2. Using photolithography, the groove regions of the anode metal electrode and the cathode metal electrode are marked on the multilayer structure (this process includes photoresist stripping with acetone and cleaning with NH3 plasma). S3. Using the ICP dry etching method, the anode groove of the anode metal electrode and the cathode groove of the cathode metal electrode are obtained by etching a multi-layer structure downward according to the groove area. S4. The cathode groove is acid-washed with hydrochloric acid (HCl:H2O=1:10) to remove surface oxides. Then, based on the cathode groove, the cathode preparation area of ​​the cathode metal electrode is marked by photolithography. Finally, electron beam evaporation is performed (electron beam energy 3KV, vacuum degree P≤10). -3 Pa), metal evaporation (Ti / Al / Ni / Au alloy evaporation) is performed in the cathode preparation area, and after the metal evaporation is completed, the evaporated metal is annealed in an inert gas (N2) atmosphere to obtain a cathode ohmic contact metal electrode as the cathode metal electrode; S5. Deposit intercalation on the surface of the second barrier layer; the specific steps of the intercalation deposition include: depositing Al2O3 in the ALD reaction chamber using trimethylaluminum (TMAl) and H2O, and depositing TiO2 using titanium tetraisopropoxide (TTIP) and H2O, while simultaneously changing the Al... x Ti 1-xThe number of TiO2 deposition cycles between each Al2O3 deposition cycle in the O system controls the metal concentration of Al2O3 and TiO2 to obtain an AlTiO layer. Then, the preparation area for intercalation is marked on the AlTiO layer using photolithography. Finally, the excess AlTiO layer is removed using the ALE atomic layer etching method, and the remaining AlTiO layer is used as the intercalation layer. S6. Based on the anode groove, after marking the anode fabrication area of ​​the anode metal electrode using photolithography, electron beam evaporation (electron beam energy 3KV, vacuum degree P≤10) is used. -3 In the anode preparation region, metal evaporation is performed to obtain an anode Schottky metal electrode as the anode metal electrode (this process includes photoresist stripping with acetone); the anode metal electrode is partially deposited on top of the intercalation layer so that the intercalation layer serves as an interlayer between the anode metal electrode and the second barrier layer. S7. A passivation layer is deposited using the PECVD method, and then etched using the ICP dry etching method to expose the cathode metal electrode and the anode metal electrode.

[0052] Specifically, in step S1, metal-organic chemical vapor deposition (MOCVD) is used to precisely control the growth of each layer of material on substrate 1 to form a high-quality multilayer structure. This method enables atomic-level layer thickness control and interface quality optimization, laying the foundation for subsequent device performance. The materials and thicknesses of the nucleation layer 2, the buffer layer 3, the first channel layer 4, the first barrier layer 5, the second channel layer 6, and the second barrier layer 7 can be selected and adjusted according to actual needs.

[0053] Furthermore, steps S2 and S3 involve photolithography and ICP dry etching, the purpose of which is to precisely define the formation areas of the anode metal electrode 9 and the cathode metal electrode 10, ensuring good contact between the electrodes and the multilayer structure and the geometric accuracy of the device. ICP dry etching is chosen because of its high anisotropy and good etching selectivity, which can effectively form the desired groove structure.

[0054] In practical applications, step S4 involves acid pickling of the cathode groove to remove any natural oxides or process residues that may be present on the surface, ensuring that subsequent metal evaporation forms a low-resistance ohmic contact. Subsequently, a Ti / Al / Ni / Au alloy is deposited by electron beam evaporation and annealed to form a stable cathode ohmic contact metal electrode. The annealing temperature and time can be optimized based on the selected metal material and the desired contact resistance.

[0055] Step S5 is the key step in this application, where the intercalation layer 11 is prepared using atomic layer deposition (ALD). ALD technology enables precise control of film thickness and excellent uniformity. By adjusting the alternating pulses of trimethylaluminum (TMAl) and tetraisopropoxide titanium (TTIP) precursors, the number of deposition cycles for Al2O3 and TiO2 can be precisely controlled, thereby regulating the metal concentrations of Al and Ti in the system to obtain an AlTiO intercalation layer with specific properties. Subsequently, the AlTiO layer is precisely patterned using atomic layer etching (ALE) to form the desired intercalation structure.

[0056] Further, in step S6, the anode metal electrode 9 is formed by electron beam evaporation and is designed to be partially deposited above the intercalation layer 11. This structure ensures that the intercalation layer 11 can act as a sandwich between the anode metal electrode 9 and the second barrier layer 7, thereby effectively pinching off the underlying channel while ensuring normal device conduction. The anode metal electrode 9 is typically made of a metal with a high work function to form a Schottky contact.

[0057] Finally, in step S7, the passivation layer 8 is deposited using the PECVD method to protect the device surface from environmental influences and provide electrical isolation. Subsequently, the passivation layer 8 is patterned using ICP dry etching to expose the anode metal electrode 9 and the cathode metal electrode 10, facilitating subsequent electrical connections and packaging.

[0058] The proposed solution utilizes atomic layer deposition (ALD) technology to fabricate the intercalation layer 11, effectively addressing the complex process challenges inherent in traditional P-GaN layer fabrication. Specifically, the ALD method enables precise thickness control and compositional regulation of the AlTiO thin film, avoiding the magnesium doping and high-temperature activation steps required for P-GaN, thus significantly simplifying the fabrication process. This simplified deposition process means that the introduction of the intercalation layer 11 does not increase the wafer fabrication cycle or production cost. Instead, it leverages its P-GaN-like properties to form an effective interlayer between the anode metal electrode 9 and the second barrier layer 7, thereby pinching off the underlying channel under reverse bias and suppressing leakage current. Simultaneously, by precisely controlling the relative position of the anode metal electrode 9 and the intercalation layer 11, normal device conduction under forward bias is ensured, avoiding the problem of the channel always being pinched off.

[0059] The above-described fabrication method enables the low-cost, high-efficiency manufacturing of Schottky diodes. In particular, by employing ALD technology to deposit AlTiO intercalation layers, the complex doping and high-temperature activation steps of traditional P-GaN processes are avoided, significantly shortening the wafer fabrication cycle and reducing production costs and process complexity. Furthermore, the devices fabricated using this method effectively reduce reverse leakage current while maintaining ultra-high breakdown voltage and high stability, thus demonstrating significant application potential in low-loss, high-power radio frequency energy transfer systems.

[0060] In this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, without necessarily requiring or implying any such actual relationship or order between these entities or operations.

[0061] The use of terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refers to specific features, structures, materials, or characteristics described in connection with the described embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0062] The above description is merely an embodiment of the present invention and is not intended to limit the scope of protection of the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A Schottky diode for a radio frequency power transfer system, comprising a multilayer structure, said multilayer structure comprising a substrate (1), a nucleation layer (2), a buffer layer (3), a first channel layer (4), a first barrier layer (5), a second channel layer (6), a second barrier layer (7), and a passivation layer (8) stacked sequentially, characterized in that, It also includes an anode metal electrode (9) and a cathode metal electrode (10) respectively disposed on the left and right sides of the multilayer structure. The anode metal electrode (9) and the cathode metal electrode (10) are electrically connected to the buffer layer (3) and the layer structure above it according to a preset equivalent circuit. The upper ends of the anode metal electrode (9) and the cathode metal electrode (10) are fastened to the upper surface of the second barrier layer (7). An intercalation layer (11) is also provided between the anode metal electrode (9) and the second barrier layer (7) as a sandwich layer.

2. The Schottky diode for a radio frequency power transfer system according to claim 1, characterized in that, The equivalent circuit includes a field-effect transistor (14) composed of the intercalation layer (11) and the second barrier layer (7), a first Schottky diode (15) composed of the first barrier layer (5), the second channel layer (6) and the second barrier layer (7), and a second Schottky diode (16) composed of the buffer layer (3), the first channel layer (4) and the first barrier layer (5). The anode metal electrode (9) serves as the anode (17) and is simultaneously connected to the gate of the field-effect transistor (14), the source of the field-effect transistor (14), and the positive terminal of the second Schottky diode (16); the drain of the field-effect transistor (14) is connected to the positive terminal of the first Schottky diode (15); and the cathode metal electrode (10) serves as the cathode (18) and is simultaneously connected to the negative terminal of the first Schottky diode (15) and the negative terminal of the second Schottky diode (16).

3. The Schottky diode for a radio frequency power transfer system according to claim 1, characterized in that, The intercalation layer (11) is made of AlTiO material.

4. The Schottky diode for a radio frequency power transfer system according to claim 1, characterized in that, The buffer layer (3), the first channel layer (4) and the second channel layer (6) are all made of GaN material.

5. The Schottky diode for a radio frequency power transfer system according to claim 4, characterized in that, The thickness of the buffer layer (3) is 2-3µm; the thickness of the first channel layer (4) is 40-60nm; and the thickness of the second channel layer (6) is 30-45nm.

6. The Schottky diode for a radio frequency power transfer system according to claim 1, characterized in that, Both the first barrier layer (5) and the second barrier layer (7) are made of AlGaN material.

7. The Schottky diode for a radio frequency power transfer system according to claim 6, characterized in that, The thickness of the first barrier layer (5) and the second barrier layer (7) is 20-30 nm.

8. The Schottky diode for a radio frequency power transfer system according to claim 1, characterized in that, The thickness of the nucleation layer (2) is 200-300 nm.

9. The Schottky diode for a radio frequency power transfer system according to claim 1, characterized in that, The passivation layer (8) is made of SiN material.

10. A method for fabricating a Schottky diode for a radio frequency power transfer system as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Using a metal-organic chemical vapor deposition method, the nucleation layer, the buffer layer, the first channel layer, the first barrier layer, the second channel layer, and the second barrier layer are sequentially grown on the substrate; S2. Using photolithography, mark the groove regions of the anode metal electrode and the cathode metal electrode on the multilayer structure; S3. Using the ICP dry etching method, the multilayer structure is etched downwards along the groove region to obtain the anode groove of the anode metal electrode and the cathode groove of the cathode metal electrode; S4. The cathode groove is acid-washed with hydrochloric acid to remove surface oxides. Then, based on the cathode groove, the cathode preparation area of ​​the cathode metal electrode is marked by photolithography. Then, metal is deposited in the cathode preparation area by electron beam evaporation. After the metal is deposited, the deposited metal is annealed in an inert gas atmosphere to obtain a cathode ohmic contact metal electrode as the cathode metal electrode. S5. Deposit the intercalation layer on the upper surface of the second barrier layer; S6. Based on the anode groove, after marking the anode preparation area of ​​the anode metal electrode using photolithography, metal is deposited in the anode preparation area using electron beam evaporation to obtain an anode Schottky metal electrode as the anode metal electrode; the anode metal electrode is partially deposited above the intercalation layer so that the intercalation layer serves as an interlayer between the anode metal electrode and the second barrier layer; S7. The passivation layer is deposited using the PECVD method, and the passivation layer is etched using the ICP dry etching method to expose the cathode metal electrode and the anode metal electrode.

Images