A schottky diode for a radio frequency energy transfer system and a method of making the same

Abstract

The application provides a Schottky diode for a radio frequency energy transmission system and a preparation method thereof, and relates to the technical field of Schottky barrier diodes. The Schottky diode comprises an anode metal electrode and a cathode metal electrode arranged on the left and right sides of a multilayer structure respectively, the anode metal electrode and the cathode metal electrode are respectively electrically connected with a buffer layer and a layer structure above the buffer layer according to a preset equivalent circuit, the upper ends of the anode metal electrode and the cathode metal electrode are clamped on the upper surface of a second barrier layer, and an interlayer 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 flow period, high production cost and large process difficulty in the existing preparation process, significantly reduces the reverse leakage current, simplifies the preparation process, and improves the performance and preparation efficiency of the device.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of Schottky barrier diode, in particular to a Schottky diode for radio frequency energy transmission system and a preparation method thereof. BACKGROUND

[0002] The existing double-channel Schottky barrier diode generally forms a MOS structure by depositing a gate dielectric (P-GaN) in the channel during the wafer processing to achieve the effect of suppressing reverse leakage, so the multilayer structure in the existing double-channel Schottky barrier diode is generally stacked in a ladder shape, the wafer processing is complex, and the P-GaN needs to be handled separately, so multiple etching steps often need to be designed, resulting in a long wafer processing cycle and high production cost, and the P-GaN also needs to be doped with Mg and activated by high temperature, so the overall process is difficult.

[0003] At present, there is no effective technical solution to the above problems. SUMMARY

[0004] The present application aims to provide a Schottky diode for radio frequency energy transmission system and a preparation method thereof, which solves the problems of complex process, long wafer processing cycle, high production cost and difficult process in the preparation process of the existing double-channel Schottky barrier diode, significantly reduces reverse leakage, simplifies the preparation process, and improves the performance and preparation efficiency of the device.

[0005] In a first aspect, the present application provides a Schottky diode for radio frequency energy transmission system, comprising a multilayer structure, 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 in turn, and further comprising an anode metal electrode and a cathode metal electrode arranged on the left and right sides of the multilayer structure respectively, the anode metal electrode and the cathode metal electrode are both electrically connected to the buffer layer and the layer structure above it according to a predetermined equivalent circuit, and the upper ends of the anode metal electrode and the cathode metal electrode are both clamped on the upper surface of the second barrier layer, and an interlayer is further arranged between the anode metal electrode and the second barrier layer as an interlayer.

[0006] The Schottky diode for radio frequency energy transmission system provided by the present application optimizes the structure by designing the interlayer, simplifies the preparation steps in the preparation process, can minimize the factors that may cause yield and device performance to decline in the preparation process, and achieves the effect of further improving the yield of the device.

[0007] Further, the equivalent circuit comprises a field effect transistor composed of the interlayer 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.

[0008] The anode metal electrode is connected with the gate of the field effect transistor, the source of the field effect transistor and the positive electrode of the second Schottky diode as an anode; the drain of the field effect transistor is connected with the positive electrode of the first Schottky diode; and the cathode metal electrode is connected with the negative electrode of the first Schottky diode and the negative electrode of the second Schottky diode as a cathode.

[0009] By precisely controlling the electrical behavior of each component, especially the effective inhibition of the electric field by the field effect transistor under reverse bias, the reverse blocking capability and reliability of the device are significantly improved, which makes it have great potential in low-loss and high-power radio frequency energy transmission systems.

[0010] Further, the interlayer is made of AlTiO material.

[0011] Further, the buffer layer, the first channel layer and the second channel layer are all made of GaN material.

[0012] Further, 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.

[0013] Further, the first barrier layer and the second barrier layer are both made of AlGaN material.

[0014] Further, the thickness of the first barrier layer and the second barrier layer is both 20-30 nm.

[0015] Further, the thickness of the nucleation layer is 200-300 nm.

[0016] Further, the passivation layer is made of SiN material.

[0017] In a second aspect, the present application provides a preparation method for preparing the Schottky diode for radio frequency energy transmission system as described above, comprising the following steps:

[0018] S1. Using a metal organic chemical vapor deposition method, sequentially growing the nucleation layer, the buffer layer, the first channel layer, the first barrier layer, the second channel layer and the second barrier layer on the substrate;

[0019] S2. Marking groove regions of the anode metal electrode and the cathode metal electrode on the multilayer structure by using a photolithography method;

[0020] S3. Obtaining an anode groove of the anode metal electrode and a cathode groove of the cathode metal electrode by etching the multilayer structure downward according to the groove regions by using an ICP dry etching method;

[0021] S4. After acid pickling the cathode groove to remove surface oxides by using hydrochloric acid, and then marking a cathode preparation region of the cathode metal electrode based on the cathode groove by using a photolithography method, performing metal evaporation in the cathode preparation region by using an electron beam evaporation method, and performing annealing treatment on the evaporated metal in an inert gas atmosphere after the metal evaporation is completed, obtaining a cathode ohmic contact metal electrode as the cathode metal electrode;

[0022] S5. Depositing the interlayer on the surface of the second barrier layer;

[0023] S6. After marking an anode preparation region of the anode metal electrode based on the anode groove by using a photolithography method, performing metal evaporation in the anode preparation region by using an electron beam evaporation method, obtaining an anode Schottky metal electrode as the anode metal electrode; and the anode metal electrode is partially deposited above the interlayer so that the interlayer serves as a sandwich layer between the anode metal electrode and the second barrier layer;

[0024] S7. Depositing the passivation layer by using a PECVD method, and etching the passivation layer by using an ICP dry etching method to expose the cathode metal electrode and the anode metal electrode.

[0025] The preparation method can realize low-cost and high-efficiency manufacturing of the double-channel Schottky barrier diode.

[0026] As can be seen from the above, the Schottky diode for the radio frequency energy transmission system provided by the application sets an interlayer as a sandwich layer between the anode metal electrode and the second barrier layer, the interlayer has a performance similar to P-GaN, can effectively pinch off the lower channel, and thus significantly reduces the reverse leakage current. Compared with the complex process of separately processing P-GaN, designing multiple etching steps, performing magnesium doping and high-temperature activation in the prior art, the interlayer of the application only needs to be deposited in the tape-out process, without additional doping and high-temperature activation, greatly simplifying the tape-out process, shortening the tape-out period, and significantly reducing the production cost and process difficulty. Therefore, the application effectively solves the problems of complex process, long tape-out period, high production cost and large process difficulty in the preparation process of the existing double-channel Schottky barrier diode, and provides a more economical and efficient solution.

[0027] Other features and advantages of the present application will be set forth in the description that follows, and in part will be apparent from the description, or can be learned by practice of the application. The purposes and other advantages of the present application will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 A structure schematic diagram of a Schottky diode for a radio frequency energy transmission system provided by an embodiment of the present application.

[0029] Figure 2 An equivalent circuit diagram preset in an embodiment of the present application.

[0030] Figure 3 A flow chart of a preparation method provided by an embodiment of the present application.

[0031] REFERENCE NUMERALS:

[0032] 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, interlayer; 12, first part; 13, second part; 14, field effect transistor; 15, first Schottky diode; 16, second Schottky diode; 17, anode; 18, cathode. DETAILED DESCRIPTION

[0033] Embodiments of the present application are described in detail below with reference to the attached drawings, wherein the same or similar components have the same or similar designations throughout the several figures of the drawings and any alterations to the components or any additions to the figures are indicated by corresponding bond numbers or reference numerals. The embodiments described below are exemplary only and are not intended to be limiting of the present application.

[0034] In the description of the present application, it is to be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like are based on the orientations or positional relationships shown in the drawings, and are merely for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0035] In the description of the present application, it is required to explain that, unless otherwise explicitly specified and limited, the terms "mount", "connect", "connection" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection or can communicate with each other; it can be directly connected, or indirectly connected through intermediate medium, or the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0036] In the present application, unless otherwise explicitly specified and limited, the "upper" or "lower" of the first feature to the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the "upper", "above" and "on" of the first feature to the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The "under", "below" and "under" of the first feature to the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0037] The following disclosure provides many different embodiments or examples for implementing different structures of the present application. In order to simplify the disclosure of the present application, the components and arrangements of specific examples are described in the following. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeatedly refer to the same reference numerals and / or reference letters in different examples, and such repetition is for the purpose of simplification and clarity, and does not indicate the relationship between the various embodiments and / or arrangements discussed. In addition, the present application provides examples of various specific processes and materials, but those skilled in the art can realize the application of other processes and / or the use of other materials.

[0038] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] The Schottky diode of the present application effectively solves the problems of complex process, long flow period, high production cost and difficult process caused by P-GaN gate medium in the prior art through ingenious structural design. The key is that the interlayer 11 is arranged as an interlayer between the anode metal electrode 9 and the second barrier layer 7. The interlayer 11 has a performance similar to P-GaN, and its main function is to pinch off the channel below when the anode metal electrode 9 applies voltage, thereby effectively suppressing reverse leakage. Unlike the traditional P-GaN gate medium, the introduction of the interlayer 11 does not require magnesium (Mg) doping and high-temperature activation treatment, and does not require the design of a complex multi-channel etching step. The interlayer 11 only needs to be implemented through a simple deposition process during the flow process, for example, through atomic layer deposition (ALD) technology to accurately control its thickness and composition. This simplified process flow significantly shortens the flow period, reduces production cost and process difficulty.

[0043] During device operation, the anode metal electrode 9 forms electrical contact with the second barrier layer 7 through the interlayer 11. When the anode metal electrode 9 applies a forward bias, the channel below the interlayer 11 is opened, and the current is transmitted through the first channel layer 4 and the second channel layer 6. When a reverse bias is applied, the pinch-off effect of the interlayer 11 can effectively suppress the reverse current, thereby reducing the leakage. It needs to be particularly emphasized that the anode metal electrode 9 must have a part deposited above the interlayer 11 to ensure that the interlayer 11 can be effectively applied with voltage and play its pinch-off role. If the anode metal electrode 9 fails to contact the interlayer 11, the channel below the interlayer 11 will always be in a pinched-off state, causing the device to fail to conduct, thereby losing its diode function. Therefore, the synergy of the interlayer 11 and the anode metal electrode 9 is the key to achieving low leakage and normal conduction.

[0044] The Schottky diode proposed in the present application exhibits significant technical contribution in solving the problems of the prior art. The traditional existing double-channel Schottky barrier diode usually adopts P-GaN gate medium to suppress reverse leakage, but this leads to complex flow process, separate processing of P-GaN, involves multi-channel etching steps, thereby prolonging the flow period and increasing the production cost. In addition, the preparation of P-GaN also requires magnesium (Mg) doping and high-temperature activation treatment, further increasing the process difficulty.

[0045] In contrast, the present application ingeniously avoids the above problems by introducing the interlayer 11 as an interlayer. The interlayer 11 has a performance similar to P-GaN, which can effectively pinch off the channel below and reduce reverse leakage. However, unlike P-GaN, the preparation process of the interlayer 11 is greatly simplified. The interlayer 11 only needs to be deposited during the flow process, for example, through atomic layer deposition (ALD) technology, without the need for magnesium (Mg) doping and high-temperature activation treatment. This simplified process flow significantly shortens the flow period, reduces production cost and process difficulty.

[0046] Specifically, the Schottky diode of the present application realizes effective control of the channel by setting the interlayer 11 between the anode metal electrode 9 and the second barrier layer 7. The introduction of the interlayer 11 makes the device structure no longer need to be stacked into a complex ladder shape like the traditional P-GaN device, thereby simplifying the overall flow process. For example, during preparation, there is no need to perform multi-channel etching to form a P-GaN gate dielectric, but the interlayer 11 can be directly deposited on the second barrier layer 7, and then part of the anode metal electrode 9 is deposited thereon. This simplification in the process not only improves production efficiency, but also reduces the technical requirements for equipment and operators. Therefore, the Schottky diode of the present application not only maintains or even improves the electrical performance, but also significantly optimizes the preparation process, providing a new solution for the low-cost and high-efficiency manufacturing of high-performance electronic devices.

[0047] Reference is made to the accompanying drawings Figure 2 In some embodiments, the equivalent circuit includes a field effect transistor 14 (here, an E-mode HEMT, i.e., an enhancement-mode high electron mobility field effect transistor, instead of a traditional p-GaN HEMT) composed of the interlayer 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;

[0048] Wherein the anode metal electrode 9 is connected to the gate of the field effect transistor 14, the source of the field effect transistor 14 and the positive pole of the second Schottky diode 16 as the anode 17; the drain of the field effect transistor 14 is connected to the positive pole of the first Schottky diode 15; the cathode metal electrode 10 is connected to the negative pole of the first Schottky diode 15 and the negative pole of the second Schottky diode 16 as the cathode 18;

[0049] The equivalent circuit of the diode is formed by the first part 12 and the second part 13 in parallel, wherein the first part 12 is equivalent to a first Schottky diode 15 and a field effect transistor 14 in series, and the second part 13 is a second Schottky diode 16. The field effect transistor 14 in the first part 12 is in an off state at zero bias. Therefore, when a forward bias is applied to the anode, the forward conduction current mainly flows out of the second Schottky diode 16 when the voltage is greater than the turn-on voltage of the second Schottky diode 16 and less than the threshold voltage of the field effect transistor 14. As the anode voltage gradually increases to be greater than the threshold voltage, the field effect transistor 14 will be in an on state, and at this 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 bear part 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. The diode has the characteristics of low leakage current, super-high breakdown voltage and high stability, and has great potential for application in low-loss and high-power radio frequency energy transmission systems.

[0050] Specifically, the construction of the above-mentioned equivalent circuit aims to optimize the electrical performance of the Schottky diode. Among them, the field effect transistor 14 is composed of the interlayer 11 and the second barrier layer 7, which is designed as an enhanced high electron mobility field effect transistor (E-mode HEMT) to replace the traditional p-GaN HEMT, thereby simplifying the process flow and reducing the cost. The first Schottky diode 15 is composed of the first barrier layer 5, the second channel layer 6 and the second barrier layer 7, and the second Schottky diode 16 is composed of the buffer layer 3, the first channel layer 4 and the first barrier layer 5. The synergistic effect of these components is the key to achieving excellent performance of the device.

[0051] In terms of electrical connection, the anode metal electrode 9, as the anode of the device, is designed to be connected to the gate of the field effect transistor 14, the source of the field effect transistor 14 and the positive electrode of the second Schottky diode 16 at the same time. This connection mode ensures that the anode voltage can control the switching state of the field effect transistor 14 and the conduction of the second Schottky diode 16 at the same time. The drain of the field effect transistor 14 is connected to the positive electrode of the first Schottky diode 15, so that after the field effect transistor 14 is turned on, the current can pass through the first Schottky diode 15. The cathode metal electrode 10, as the cathode of the device, is connected to the negative electrode of the first Schottky diode 15 and the negative electrode of the second Schottky diode 16 at the same time, providing a return path for the current.

[0052] The scheme of the present application builds 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 way. Specifically, the field effect transistor 14 is in an off state at zero bias, ensuring the stability of the device at low voltage. Under forward bias, when the voltage reaches the turn-on voltage of the second Schottky diode 16, the current is first conducted through the second Schottky diode 16, providing an initial conduction path. As the voltage further rises and exceeds the threshold voltage of the field effect transistor 14, the field effect transistor 14 is turned on, allowing the first Schottky diode 15 to also participate in conduction, thereby achieving double-channel cooperative conduction and effectively reducing the forward on-resistance. Under reverse bias, the field effect transistor 14 can withstand part 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 the reverse leakage and improving the breakdown voltage of the device.

[0053] Through the above equivalent circuit design, the Schottky diode of the present application can achieve low leakage, ultra-high breakdown voltage characteristics and high stability. Compared with devices with only basic structures, this scheme precisely controls the electrical behavior of each component, especially the effective suppression of the electric field by the field effect transistor 14 under reverse bias, significantly improving the reverse blocking capability and reliability of the device, making it have great potential for application in low-loss and high-power radio frequency energy transmission systems.

[0054] In some embodiments, the interlayer 11 is made of AlTiO material.

[0055] In some embodiments, the buffer layer 3, the first channel layer 4 and the second channel layer 6 are all made of GaN material.

[0056] Further, the buffer layer 3 is made of C (carbon) doped GaN material, with a doping concentration of 10 18 cm -3 .

[0057] 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.

[0058] In some embodiments, the first barrier layer 5 and the second barrier layer 7 are both made of AlGaN material.

[0059] In some embodiments, the thickness of the first barrier layer 5 and the second barrier layer 7 is both 20-30 nm.

[0060] In some embodiments, the thickness of the nucleation layer 2 is 200-300 nm.

[0061] In some embodiments, the passivation layer 8 is made of SiN material.

[0062] With reference to the accompanying drawings, which depict preferred embodiments of the application, Figure 3 the present application provides a preparation method for preparing the Schottky diode for the radio frequency energy transmission system in the above embodiments, comprising the following steps:

[0063] S1. Using a metal organic chemical vapor deposition method, sequentially growing a nucleation layer, a buffer layer, a first channel layer, a first barrier layer, a second channel layer, and a second barrier layer on a substrate;

[0064] S2. Using a photolithography method, marking a groove area of an anode metal electrode and a cathode metal electrode on the multilayer structure (this process includes using acetone for photoresist stripping and using NH3 plasma for cleaning treatment);

[0065] S3. Using an ICP dry etching method, etching the multilayer structure downward according to the groove area to obtain an anode groove of the anode metal electrode and a cathode groove of the cathode metal electrode;

[0066] S4. Using hydrochloric acid (HCl:H2O=1:10) to acid wash the cathode groove to remove surface oxides, and then based on the cathode groove, using a photolithography method to mark a cathode preparation area of the cathode metal electrode, and then using an electron beam evaporation method (electron beam energy of 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, annealing treatment is performed on the evaporated metal in an inert gas (N2) atmosphere to obtain a cathode ohmic contact metal electrode as the cathode metal electrode;

[0067] S5. Depositing an interlayer on the surface of the second barrier layer; the specific steps of depositing the interlayer include: in an ALD reaction chamber, depositing Al2O3 by trimethylaluminum (TMAl) and H2O, and depositing TiO2 by titanium tetraisopropoxide (TTIP) and H2O, while controlling the metal concentration of Al2O3 and TiO2 by changing the number of TiO2 deposition periods between each Al2O3 deposition period in the Al x Ti 1-x O system, then using a photolithography method to mark an interlayer preparation area on the AlTiO layer, and finally using an ALE atomic layer etching method to remove excess AlTiO layer, and using the remaining AlTiO layer as the interlayer;

[0068] S6. Based on the anode groove, using a photolithography method to mark an anode preparation area of the anode metal electrode, and then using an electron beam evaporation method (electron beam energy of 3KV, vacuum degree P≤10 -3In the anode preparation area, metal evaporation is performed to obtain an anode Schottky metal electrode as the anode metal electrode (this process includes photoresist stripping using acetone); the anode metal electrode is partially deposited above the interlayer so that the interlayer serves as an interlayer between the anode metal electrode and the second barrier layer;

[0069] S7. A passivation layer is deposited using a PECVD method, and the passivation layer is etched by an ICP dry etching method to expose the cathode metal electrode and the anode metal electrode.

[0070] Specifically, in step S1, a metal organic chemical vapor deposition (MOCVD) method is used to precisely control the growth of each layer of material on the substrate 1 to form a high-quality multilayer structure. This method can achieve atomic-level control of layer thickness and optimization of interface quality, 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.

[0071] Further, steps S2 and S3 involve photolithography and ICP dry etching, which aims to precisely define the formation area 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 precision of the device. ICP dry etching is chosen because of its high anisotropy and good etching selectivity, which can effectively form the required groove structure.

[0072] In practical applications, step S4 acid washes the cathode groove, aiming to remove any natural oxides or process residues that may be present on the surface to ensure that the subsequent metal evaporation forms an ohmic contact with low resistance. Subsequently, Ti / Al / Ni / Au alloy is deposited by electron beam evaporation and annealed to form a stable cathode ohmic contact metal electrode. The temperature and time of the annealing process can be optimized according to the selected metal material and the required contact resistance.

[0073] Step S5 is the key to this application, which prepares the interlayer 11 by atomic layer deposition (ALD) method. ALD technology can achieve precise control of film thickness and excellent uniformity. By adjusting the alternating pulses of trimethylaluminum (TMAl) and titanium tetraisopropoxide (TTIP) precursors, the deposition cycle number of Al2O3 and TiO2 can be precisely controlled, and the metal concentration of Al and Ti in the system can be adjusted, thereby obtaining an AlTiO interlayer with specific properties. Subsequently, the AlTiO layer is precisely patterned using atomic layer etching (ALE) method to form the required interlayer structure.

[0074] Further, in step S6, the anode metal electrode 9 is formed by an electron beam evaporation method and is designed to be partially deposited above the interlayer 11. This structure ensures that the interlayer 11 can serve as an interlayer between the anode metal electrode 9 and the second barrier layer 7, thereby achieving effective pinch-off of the underlying channel while ensuring normal conduction of the device. The material of the anode metal electrode 9 is usually selected to be a metal with a high work function to form a Schottky contact.

[0075] Finally, in step S7, the passivation layer 8 is deposited by a PECVD method, which aims to protect the surface of the device from the environment and provide electrical isolation. Subsequently, the passivation layer 8 is patterned by ICP dry etching to expose the anode metal electrode 9 and the cathode metal electrode 10, facilitating subsequent electrical connection and packaging.

[0076] The scheme of the present application effectively solves the complex process challenges faced in the preparation process of the traditional P-GaN layer by introducing atomic layer deposition (ALD) technology to prepare the interlayer 11. Specifically, the ALD method can achieve precise thickness control and component regulation of the AlTiO thin film, avoiding the magnesium doping and high-temperature activation steps required for P-GaN, thereby significantly simplifying the preparation process. It is precisely due to this simplified deposition process that the introduction of the interlayer 11 no longer increases the flow period and production cost, but instead can utilize its similar P-GaN performance 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. At the same time, by precisely controlling the relative position of the anode metal electrode 9 and the interlayer 11, it is ensured that the device can normally conduct under forward bias, avoiding the problem of the channel being always in a pinched-off state.

[0077] Through the above preparation method, the present application can achieve low-cost and high-efficiency manufacturing of Schottky diodes. In particular, by depositing the AlTiO interlayer using ALD technology, the complex doping and high-temperature activation steps in the traditional P-GaN process are avoided, significantly shortening the flow period and reducing production cost and process difficulty. In addition, the device prepared by this method can effectively reduce reverse leakage and maintain ultra-high breakdown voltage and high stability, thereby exhibiting great application potential in low-loss and high-power radio frequency energy transmission systems.

[0078] In this document, relational terms such as first and second and the like can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.

[0079] Reference to terms "one implementation", "some implementations", "certain implementations", "an example", "a specific example", or "some examples" etc., mean that a particular feature, structure, material or characteristic being described is included in at least one implementation or example of the present application. Such appearances of these terms in this specification are not necessarily referring to the same implementation or example. Furthermore, the described features, structures, materials or characteristics can be combined in any suitable manner in one or more implementations or examples.

[0080] The above descriptions are only some embodiments of the present application, and are not used to limit the protection scope of the present application. The present application can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

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 disposed between the anode metal electrode (9) and the second barrier layer (7) as a sandwich layer. The intercalation layer (11) is made of AlTiO material. The intercalation layer (11) covers part of the surface of the second barrier layer (7). The surface of the second barrier layer (7) between the intercalation layer (11) and the cathode metal electrode (10) is covered by the passivation layer (8). The intercalation layer (11) is used to clamp the lower channel under reverse bias to suppress leakage current. The equivalent circuit includes a field-effect transistor (HEMT) composed of the intercalation layer (11) and the second barrier layer (7), a first Schottky diode (SBD1) composed of the first barrier layer (5), the second channel layer (6) and the second barrier layer (7), and a second Schottky diode (SBD2) 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 and is simultaneously connected to the gate of the HEMT, the source of the HEMT, and the positive terminal of the second Schottky diode (SBD2); the drain of the HEMT is connected to the positive terminal of the first Schottky diode (SBD1); and the cathode metal electrode (10) serves as the cathode and is simultaneously connected to the negative terminal of the first Schottky diode (SBD1) and the negative terminal of the second Schottky diode (SBD2).

2. 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.

3. The Schottky diode for a radio frequency power transfer system according to claim 2, 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.

4. 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.

5. The Schottky diode for a radio frequency power transfer system according to claim 4, characterized in that, The thickness of the first barrier layer (5) and the second barrier layer (7) is 20-30 nm.

6. 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.

7. 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.

8. A method for fabricating a Schottky diode for a radio frequency power transfer system as described in any one of claims 1-7, 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.

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