N-polarity GaNAlGaN heterojunction transverse SBD with mixed metal anode and preparation method of N-polarity GaNAlGaN heterojunction transverse SBD

Abstract

The invention discloses an N-polarity GaNAlGaN heterojunction transverse SBD with a mixed metal anode and a preparation method. The N-polarity GaNAlGaN heterojunction transverse SBD comprises a substrate layer, and an unintentionally doped N-polarity GaN buffer layer, a Si doped N-polarity AlGaN barrier layer, an unintentionally doped N-polarity AlGaN barrier layer and an unintentionally doped N-polarity GaN channel layer which are sequentially positioned on the substrate layer, the cathode is located on the N-polarity GaN channel layer and is of a circular structure; the passivation layer is located on the cathode and the remaining N-polarity GaN channel layer; the mixed anode penetrates through the passivation layer in the central region of the annular structure until reaching the upper surface of the N-polarity GaN channel layer; the mixed anode comprises a high work function metal and a plurality of low work function metals distributed at intervals; each low-work-function metal is located on the N-polarity GaN channel layer; the high work function metal is located on the N-polarity GaN channel layer, all the low work function metal and part of the passivation layer.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductors, and particularly relates to an N-polarity GaN_AlGaN heterojunction lateral SBD with a hybrid metal anode and a preparation method thereof. Background Art

[0002] Most of the existing rectifier diodes and power devices rely on silicon (Si)-based materials. However, with the continuous improvement of the requirements for power density, efficiency, and miniaturization in modern electronic devices, the traditional Si-based materials have gradually approached the limit of their intrinsic material properties, resulting in increasingly obvious limitations under the demands of high performance, compactness, and high power density. Compared with the traditional Si-based materials, GaN-based semiconductor materials have shown significant advantages in the manufacture of high-power, high-frequency, and high-temperature electronic devices and optoelectronic devices due to their large bandgap, high electron saturation velocity, excellent thermal conductivity, outstanding high-temperature and high-pressure characteristics, and excellent corrosion resistance. In addition, the excellent thermal conductivity, temperature stability, and corrosion resistance of GaN make its reliability under extreme working conditions significantly better than that of silicon materials. Therefore, GaN devices are widely regarded as an ideal choice for high-frequency, high-power, and high-performance applications, especially suitable for fields such as radio frequency power amplifiers, electric vehicle power supplies, solar inverters, and 5G communication base stations.

[0003] In recent years, devices based on N-polarity GaN / AlGaN heterojunctions have developed rapidly and attracted extensive attention in the academic community due to characteristics such as low contact resistance, strong two-dimensional electron gas (2DEG) confinement, excellent gate control ability, and high-frequency response. However, the continuous progress of power electronics technology and the expansion of its application fields have put forward higher requirements for the performance, efficiency, and reliability of power devices. The technical challenges faced by the existing N-polarity GaN / AlGaN heterojunction Schottky diodes mainly stem from their unique material structure and polarity characteristics. The channel layer of this type of diode is located above the device, and the metal is in direct contact with the channel layer. The high surface state density of the N-polarity GaN material results in a low Schottky barrier when the metal contacts GaN. This characteristic causes a large leakage current in the device under reverse bias, reducing the breakdown voltage ability and making it unable to effectively withstand a high reverse voltage. Therefore, the N-polarity GaN / AlGaN heterojunction Schottky diode often faces poor stability and reliability problems in high-temperature, high-power, or high-voltage applications. Thus, the breakdown voltage and reliability of N-polarity GaN / AlGaN heterojunction devices face severe challenges, and there is an urgent need to design an N-polarity GaN / AlGaN heterojunction Schottky diode with high breakdown voltage and reliability at the same time. Summary of the Invention

[0004] To solve the above problems existing in the prior art, the present invention provides an N-polarity GaN_AlGaN heterojunction lateral SBD with a hybrid metal anode and a preparation method thereof. The technical problems to be solved by the present invention are realized through the following technical solutions:

[0005] In a first aspect, an embodiment of the present invention provides an N-polarity GaN_AlGaN heterojunction lateral SBD with a hybrid metal anode, and the N-polarity GaN_AlGaN heterojunction lateral SBD includes:

[0006] A substrate layer, an unintentionally doped N-polarity GaN buffer layer, a Si-doped N-polarity AlGaN barrier layer, an unintentionally doped N-polarity AlGaN barrier layer, and an unintentionally doped N-polarity GaN channel layer that are sequentially located on the substrate layer;

[0007] A cathode, which is located on the unintentionally doped N-polarity GaN channel layer and has an annular structure;

[0008] An ISO isolation layer, which penetrates the unintentionally doped N-polarity GaN channel layer around the device and reaches inside the unintentionally doped N-polarity GaN buffer layer;

[0009] A passivation layer, which is located on the ISO isolation layer, the cathode, and the remaining unintentionally doped N-polarity GaN channel layer;

[0010] A hybrid anode, which penetrates the passivation layer in the central region of the annular structure and reaches the upper surface of the unintentionally doped N-polarity GaN channel layer; wherein, the hybrid anode includes a high work function metal and several low work function metals distributed at intervals; each low work function metal is located on the unintentionally doped N-polarity GaN channel layer at intervals; the high work function metal is located on the unintentionally doped N-polarity GaN channel layer, all the low work function metals, and a part of the passivation layer, and has a comb-like structure.

[0011] In an embodiment of the present invention, the thickness of the unintentionally doped N-polarity GaN buffer layer is 300 nm to 600 nm.

[0012] In an embodiment of the present invention, the thickness of the Si-doped N-polarity AlGaN barrier layer is 20 nm to 50 nm, the Si doping concentration is 5×10 17 cm -3 ~8×10 18 cm -3 , and the Al component range is 0.2 to 0.35.

[0013] In an embodiment of the present invention, the thickness of the unintentionally doped N-polarity AlGaN barrier layer is 10 nm to 30 nm, and the Al component range is 0.2 to 0.35.

[0014] In one embodiment of the present invention, the thickness of the unintentionally doped N-polar GaN channel layer is 10 nm to 100 nm.

[0015] In one embodiment of the present invention, the distance between the hybrid anode and the inner ring of the cathode is 10 μm to 60 μm.

[0016] In one embodiment of the present invention, the width of each low work function metal is 2 μm to 5 μm, and the thickness is 20 nm to 40 nm.

[0017] In one embodiment of the present invention, the distance between adjacent low work function metals is 1 μm to 8 μm.

[0018] Second, an embodiment of the present invention provides a method for manufacturing an N-polar GaN_AlGaN heterojunction lateral SBD with a hybrid metal anode. The manufacturing method includes:

[0019] Obtain a substrate layer;

[0020] Successively grow an unintentionally doped N-polar GaN buffer layer, a Si-doped N-polar AlGaN barrier layer, an unintentionally doped N-polar AlGaN barrier layer, and an unintentionally doped N-polar GaN channel layer on the substrate layer;

[0021] Form a cathode with an annular structure on the unintentionally doped N-polar GaN channel layer;

[0022] Perform ion implantation on the unintentionally doped N-polar GaN channel layer around the device until an ISO isolation layer is formed in the unintentionally doped N-polar GaN buffer layer;

[0023] Deposit a passivation layer on the ISO isolation layer, the cathode, and the remaining unintentionally doped N-polar GaN channel layer;

[0024] Etch away the passivation layer in the central region of the annular structure until the upper surface of the unintentionally doped N-polar GaN channel layer forms an anode region, and deposit a number of low work function metals distributed at intervals in the anode region;

[0025] Deposit a high work function metal on the unintentionally doped N-polar GaN channel layer, all low work function metals, and a part of the passivation layer. The high work function metal has a comb-like structure, so as to form a hybrid anode composed of the high work function metal and a number of low work function metals distributed at intervals.

[0026] In one embodiment of the present invention, the manufacturing method further includes:

[0027] Etch away a part of the passivation layer on the cathode to form a cathode opening region.

[0028] Advantages of the present invention:

[0029] The N-polarity GaN_AlGaN heterojunction lateral SBD with a hybrid metal anode proposed by the present invention can significantly improve the performance of the N-polarity GaN / AlGaN heterojunction lateral SBD in high-power, high-voltage, and high-frequency application scenarios. Specifically: a hybrid structure of a low-work-function metal and a high-work-function metal is adopted at the anode, enabling the device to have a lower turn-on voltage and conduction loss under forward bias. At the same time, under reverse bias, the high Schottky barrier of the high-work-function metal suppresses the reverse leakage current and enhances the breakdown voltage of the device, making the proposed Schottky diode have better high-frequency, high-power, and high-voltage application capabilities, providing strong support for further promoting the application of GaN / AlGaN heterojunction diodes in high-efficiency and high-reliability electronic systems; the present invention realizes the combination with the existing N-polarity GaN / AlGaN heterojunction HEMT device, and further realizes the power integration of the N-polarity GaN / AlGaN heterostructure. This design scheme not only effectively reduces the volume of the power module, but also significantly improves the processing efficiency and reliability of the device. Generally speaking, through this technological innovation, the present invention can provide a feasible technical path for the large-scale application of N-polarity GaN / AlGaN heterojunction devices, and promote the wide application of such devices in high-efficiency and high-reliability power electronic systems.

[0030] The present invention will be further described in detail below with reference to the drawings and embodiments. Description of the Drawings

[0031] Figure 1 is a schematic structural diagram of an N-polarity GaN_AlGaN heterojunction lateral SBD with a hybrid metal anode provided by an embodiment of the present invention;

[0032] Figure 2 is a schematic flow chart of a preparation method of an N-polarity GaN_AlGaN heterojunction lateral SBD with a hybrid metal anode provided by an embodiment of the present invention;

[0033] Figures 3(a) to 3(l) is based on the embodiment of the present invention Figure 2 Schematic structural diagrams corresponding to each step in the preparation process.

[0034] Description of the Reference Numerals:

[0035] 1 - Substrate layer; 2 - Unintentionally doped N-polarity GaN buffer layer; 3 - Si-doped N-polarity AlGaN barrier layer; 4 - Unintentionally doped N-polarity AlGaN barrier layer; 5 - Unintentionally doped N-polarity GaN channel layer; 6 - Cathode; 7 - ISO isolation layer; 8 - Passivation layer; 9 - Low-work-function metal; 10 - High-work-function metal. Detailed Embodiments

[0036] The present invention will be further described in detail below with reference to specific embodiments, but the implementation manners of the present invention are not limited thereto.

[0037] Please refer to Figure 1 , an embodiment of the present invention provides an N-polarity GaN_AlGaN heterojunction lateral SBD with a hybrid metal anode. The N-polarity GaN_AlGaN heterojunction lateral SBD includes:

[0038] A substrate layer 1, an unintentionally doped N-polarity GaN buffer layer 2, a Si-doped N-polarity AlGaN barrier layer 3, an unintentionally doped N-polarity AlGaN barrier layer 4, and an unintentionally doped N-polarity GaN channel layer 5, which are sequentially located on the substrate layer 1;

[0039] A cathode 6, which is located on the unintentionally doped N-polarity GaN channel layer and has an annular structure;

[0040] An ISO isolation layer 7, which penetrates the unintentionally doped N-polarity GaN channel layer 5 around the device and extends into the unintentionally doped N-polarity GaN buffer layer 2;

[0041] A passivation layer 8, which is located on the ISO isolation layer 7, the cathode 6, and the remaining unintentionally doped N-polarity GaN channel layer 5;

[0042] A hybrid anode, which penetrates the passivation layer 8 in the central region of the annular structure and reaches the upper surface of the unintentionally doped N-polarity GaN channel layer 5; wherein, the hybrid anode includes a high work function metal 10 and a plurality of low work function metals 9 distributed at intervals; each low work function metal 9 is located on the unintentionally doped N-polarity GaN channel layer 5 at intervals; the high work function metal 10 is located on the unintentionally doped N-polarity GaN channel layer 5, all the low work function metals 9, and a part of the passivation layer 8 and has a comb-like structure.

[0043] In the embodiment of the present invention, the substrate layer 1 can be selected from Al2O3 (sapphire), SiC (silicon carbide), etc.

[0044] In the embodiment of the present invention, the thickness of the unintentionally doped N-polarity GaN buffer layer 2 is 300 nm to 600 nm, which is used to ensure the high-quality epitaxial growth of the device.

[0045] In the embodiment of the present invention, the thickness of the Si-doped N-polarity AlGaN barrier layer 3 is 20 nm to 50 nm, and the Si doping concentration is 5×10 17 cm -3 to 8×10 18 cm -3 , and the Al component range is 0.2 to 0.35. Here, a graded barrier layer can also be used to optimize the electrical characteristics of the device.

[0046] In the embodiment of the present invention, the thickness of the unintentionally doped N-polar AlGaN barrier layer 4 is 10 nm to 30 nm, and the Al composition range is 0.2 to 0.35, so as to further improve the interface performance of the device.

[0047] In the embodiment of the present invention, the thickness of the unintentionally doped N-polar GaN channel layer 5 is 10 nm to 100 nm.

[0048] In the embodiment of the present invention, the material of the passivation layer 8 can be SiN, and the thickness is 3 nm to 120 nm.

[0049] In the embodiment of the present invention, for the mixed anode, the low work function metal 9 can be Mo or W, etc., the high work function metal 10 can be Ni / Au or Pt / Au, etc., and the cathode 6 can be an ohmic metal stack such as Ti / Al / Ni / Au to ensure the current conduction and reliability of the device.

[0050] In the embodiment of the present invention, the distance between the cathode 6 and the mixed anode can be adjusted according to the breakdown voltage design requirements. Usually, the distance between the mixed anode and the inner ring of the cathode 6 is 10 μm to 60 μm. The width of each low work function metal 9 in the mixed anode is 2 μm to 5 μm, the thickness is 20 nm to 40 nm, and the distance between adjacent low work function metals 9 is 1 μm to 8 μm. The specific width combination can be optimized according to the breakdown voltage and current conduction requirements. The number of low work function metals 9 can be flexibly designed according to the current conduction requirements of the device. There is no strict requirement for the layer thickness of the high work function metal 10 under the premise of ensuring good coverage. When the cathode 6 is Ti / Al / Ni / Au, the corresponding thickness is 10 nm to 30 nm / 100 nm to 200 nm / 35 nm to 65 nm / 30 nm to 50 nm, the inner ring radius of the circular ring structure is 90 μm to 1000 μm, and the outer ring radius is 120 μm to 1500 μm.

[0051] In addition, the N-polar GaN_AlGaN heterojunction lateral SBD with a mixed metal anode proposed by the present invention may further include an AlGaN cap layer, which is located on the unintentionally doped N-polar GaN channel layer 5, and then a passivation layer 8 is designed on the AlGaN cap layer.

[0052] The N-polar GaN_AlGaN heterojunction lateral SBD with a mixed metal anode designed in the embodiment of the present invention can be in various shapes such as circular, rectangular or hexagonal.

[0053] In summary, the N-polarity GaN_AlGaN heterojunction lateral SBD with a hybrid metal anode proposed in the embodiments of the present invention can significantly improve the performance of the N-polarity GaN / AlGaN heterojunction lateral SBD in high-power, high-voltage, and high-frequency application scenarios. Specifically: a hybrid structure of a low-work-function metal 9 and a high-work-function metal 10 is adopted at the anode, enabling the device to have a lower turn-on voltage and conduction loss under forward bias. At the same time, under reverse bias, the high Schottky barrier of the high-work-function metal 10 suppresses the reverse leakage current and enhances the breakdown voltage of the device, making the proposed Schottky diode have better high-frequency, high-power, and high-voltage application capabilities, providing strong support for further promoting the application of GaN / AlGaN heterojunction diodes in high-efficiency and high-reliability electronic systems; the present invention realizes the combination with the existing N-polarity GaN / AlGaN heterojunction HEMT device, thereby realizing the power integration of the N-polarity GaN / AlGaN heterostructure. This design scheme not only effectively reduces the volume of the power module but also significantly improves the processing efficiency and reliability of the device. Generally speaking, through this technological innovation, the present invention can provide a feasible technical path for the large-scale application of N-polarity GaN / AlGaN heterojunction devices and promote the wide application of such devices in high-efficiency and high-reliability power electronic systems.

[0054] In a second aspect, please refer to Figure 2 , the embodiments of the present invention provide a preparation method for an N-polarity GaN_AlGaN heterojunction lateral SBD with a hybrid metal anode. The preparation method includes:

[0055] S10. Obtain a substrate layer 1.

[0056] As shown in FIG. 3(a), the substrate layer 1 obtained in the embodiments of the present invention can be Al2O3, SiC, etc., and the obtained substrate layer 1 is cleaned and acid-treated.

[0057] S20. Sequentially grow an unintentionally doped N-polarity GaN buffer layer 2, an Si-doped N-polarity AlGaN barrier layer 3, an unintentionally doped N-polarity AlGaN barrier layer 4, and an unintentionally doped N-polarity GaN channel layer 5 on the substrate layer 1.

[0058] In the embodiment of the present invention, the MOCVD (Metal-Organic Chemical Vapor Deposition) process is used to grow an unintentionally doped N-polar GaN buffer layer 2, an Si-doped N-polar AlGaN barrier layer 3, an unintentionally doped N-polar AlGaN barrier layer 4, and an unintentionally doped N-polar GaN channel layer 5 on the substrate layer 1 in sequence. Among them, the grown unintentionally doped N-polar GaN buffer layer 2 is shown in Fig. 3(b), and its thickness is 300 nm to 600 nm; the grown Si-doped N-polar AlGaN barrier layer 3 is shown in Fig. 3(c), and its thickness is 20 nm to 50 nm, and the Si doping concentration is 5×10 17 cm -3 ~8×10 18 cm -3 , and the Al component range is 0.2 to 0.35; the grown unintentionally doped N-polar AlGaN barrier layer 4 is shown in Fig. 3(d), and its thickness is 10 nm to 30 nm, and the Al component range is 0.2 to 0.35; the grown unintentionally doped N-polar GaN channel layer 5 is shown in Fig. 3(e), and its thickness is 10 nm to 100 nm.

[0059] S30. A cathode 6 with an annular structure is formed on the unintentionally doped N-polar GaN channel layer 5.

[0060] In the embodiment of the present invention, the device structure obtained in S20 is cleaned, and a layer of photoresist is spin-coated and exposed on the surface of the device obtained in S20. Through the photolithography process, a cathode region is formed on the unintentionally doped N-polar GaN channel layer 5. The cathode region has an annular structure, the inner ring radius of the annular structure is 90 μm to 1000 μm, and the outer ring radius is 120 μm to 1500 μm. Then, an ohmic metal stack such as Ti / Al / Ni / Au is deposited in the cathode region by electron beam evaporation to form a cathode. The corresponding cathode 6 with a thickness of 10 nm to 30 nm / 100 nm to 200 nm / 35 nm to 65 nm / 30 nm to 50 nm is shown in Fig. 3(f), and it is annealed in an N2 atmosphere. The annealing temperature is 780 °C, and the annealing time is 30 s. All the photoresist is removed.

[0061] S40. The unintentionally doped N-polar GaN channel layer 5 around the device is ion-implanted until an ISO isolation layer 7 is formed in the unintentionally doped N-polar GaN buffer layer 2.

[0062] In the embodiment of the present invention, an ion implantation process is adopted to perform ion implantation, such as N (nitrogen) ion implantation, on the unintentionally doped N-polar GaN channel layer 5 around the device obtained in S30, and the implantation depth reaches into the unintentionally doped N-polar GaN buffer layer 2 to form an ISO isolation layer 7 as shown in FIG. 3(g). Here, the adopted ion implantation method realizes the isolation between devices by destroying the lattice structures of GaN and AlGaN and destroying the polarization two-dimensional electron gas.

[0063] S50. Deposit a passivation layer 8 on the ISO isolation layer 7, the cathode 6, and the remaining unintentionally doped N-polar GaN channel layer 5.

[0064] In the embodiment of the present invention, a passivation layer 8 made of SiN with a thickness of 3 nm to 120 nm is deposited on the ISO isolation layer 7, the cathode 6, and the remaining unintentionally doped N-polar GaN channel layer 5 by using a PECVD (Plasma Enhanced Chemical Vapor Deposition) process as shown in FIG. 3(h).

[0065] In the embodiment of the present invention, a layer of photoresist is spin-coated on the surface of the passivation layer 8 and exposed, and a part of the passivation layer 8 on the cathode 6 is etched away through a lithography process to form a cathode opening region as shown in FIG. 3(i). Remove all the photoresist.

[0066] S60. Etch away the passivation layer 8 in the central region of the circular ring structure until the upper surface of the unintentionally doped N-polar GaN channel layer 5 forms an anode region, and deposit a plurality of low work function metals 9 distributed at intervals in the anode region.

[0067] In the embodiment of the present invention, a layer of photoresist is spin-coated on the surface of the device obtained in S50 and exposed, and the passivation layer 8 in the central region of the circular ring structure is etched away through a lithography process until the upper surface of the unintentionally doped N-polar GaN channel layer 5 forms an anode region as shown in FIG. 3(j). Remove all the photoresist.

[0068] Continue to spin-coat a layer of photoresist on the surface of the device and expose it, and form a low work function metal region in the anode region through a lithography process. Then, a low work function metal such as Mo or W is deposited in the low work function metal region by using a sputtering process to deposit a plurality of low work function metals 9 distributed at intervals in the anode region as shown in FIG. 3(k), and the width of each low work function metal 9 is 2 μm to 5 μm and the thickness is 20 nm to 40 nm. Remove all the photoresist.

[0069] S70. A high work function metal 10 is deposited on the unintentionally doped N-polar GaN channel layer 5, all the low work function metals 9, and a part of the passivation layer 8. The high work function metal 10 has a comb-like structure, so as to form a hybrid anode composed of the high work function metal 10 and several low work function metals 9 distributed at intervals.

[0070] In the embodiment of the present invention, a layer of photoresist is spin-coated on the surface of the device obtained in S60 and exposed, and the entire anode region is etched through a photolithography process. Within the anode region, a high work function metal 10 such as Ni / Au or Pt / Au is deposited on the unintentionally doped N-polar GaN channel layer 5, all the low work function metals 9, and a part of the passivation layer 8 by an electron beam evaporation process as shown in Fig. 3(l). The high work function metal 10 has a comb-like structure. All the photoresist is removed.

[0071] For the embodiment of the preparation method of the second aspect, since it is basically similar to the device embodiment of the first aspect, the description is relatively simple. For the relevant parts, refer to the partial description of the device embodiment of the first aspect.

[0072] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more, unless otherwise specifically defined.

[0073] Although the present invention has been described in conjunction with various embodiments herein, however, in the process of implementing the claimed invention, those skilled in the art can understand and achieve other variations of the disclosed embodiments by referring to the description of the specification and its drawings. In the specification, the term "comprising" does not exclude other components or steps, and "a" or "one" does not exclude a plurality of cases. Certain measures are recited in different embodiments, but this does not mean that these measures cannot be combined to produce good results.

[0074] The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, several simple deductions or substitutions can be made, and all should be regarded as belonging to the protection scope of the present invention.

Claims

1. An N-polar GaN / AlGaN heterojunction lateral SBD with a hybrid metal anode, characterized in that, The N-polarity GaN_AlGaN heterojunction lateral SBD includes: A substrate layer, an unintentionally doped N-polarity GaN buffer layer, a Si-doped N-polarity AlGaN barrier layer, an unintentionally doped N-polarity AlGaN barrier layer, and an unintentionally doped N-polarity GaN channel layer that are sequentially located on the substrate layer; A cathode, which is located on the unintentionally doped N-polarity GaN channel layer and has an annular structure; An ISO isolation layer that penetrates the unintentionally doped N-polarity GaN channel layer around the device and extends into the unintentionally doped N-polarity GaN buffer layer; A passivation layer that is located on the ISO isolation layer, the cathode, and the remaining unintentionally doped N-polarity GaN channel layer; A hybrid anode that penetrates the passivation layer in the central region of the annular structure and reaches the upper surface of the unintentionally doped N-polarity GaN channel layer; wherein the hybrid anode includes a high work function metal and a plurality of low work function metals that are spaced apart; each low work function metal is spaced on the unintentionally doped N-polarity GaN channel layer; the high work function metal is located on the unintentionally doped N-polarity GaN channel layer, all the low work function metals, and a part of the passivation layer and has a comb-like structure.

2. The N-polar GaN_AlGaN heterojunction lateral SBD with a mixed metal anode according to claim 1, wherein The thickness of the unintentionally doped N-polarity GaN buffer layer is 300 nm to 600 nm.

3. The N-polar GaN_AlGaN heterojunction lateral SBD with a mixed metal anode according to claim 1, characterized in that, The thickness of the Si-doped N-polar AlGaN barrier layer is 20 nm to 50 nm, and the Si doping concentration is 5×10 17 cm -3 ~8×10 18 cm -3 , and the Al component range is 0.2 to 0.

35.

4. The N-polar GaN_AlGaN heterojunction lateral SBD with a mixed metal anode according to claim 1, characterized in that, The thickness of the unintentionally doped N-polarity AlGaN barrier layer is 10 nm to 30 nm, and the Al component range is 0.2 to 0.

35.

5. The N-polar GaN / AlGaN heterojunction lateral SBD with a hybrid metal anode according to claim 1, characterized in that, The thickness of the unintentionally doped N-polarity GaN channel layer is 10 nm to 100 nm.

6. The N-polar GaN / AlGaN heterojunction lateral SBD with a mixed metal anode according to claim 1, characterized in that, The distance between the hybrid anode and the inner ring of the cathode is 10 μm to 60 μm.

7. The N-polar GaN_AlGaN heterojunction lateral SBD with a mixed metal anode according to claim 1, characterized in that, The width of each low work function metal is 2 μm to 5 μm, and the thickness is 20 nm to 40 nm.

8. The N-polar GaN / AlGaN heterojunction lateral SBD with a mixed metal anode according to claim 1, characterized in that, The distance between adjacent low work function metals is 1 μm to 8 μm.

9. A preparation method of an N-polar GaN / AlGaN heterojunction lateral SBD with a mixed metal anode, characterized in that, The preparation method includes: Obtaining a substrate layer; Sequentially growing an unintentionally doped N-polarity GaN buffer layer, a Si-doped N-polarity AlGaN barrier layer, an unintentionally doped N-polarity AlGaN barrier layer, and an unintentionally doped N-polarity GaN channel layer on the substrate layer; Forming an annular cathode on the unintentionally doped N-polarity GaN channel layer; Performing ion implantation on the unintentionally doped N-polarity GaN channel layer around the device until an ISO isolation layer is formed in the unintentionally doped N-polarity GaN buffer layer; Depositing a passivation layer on the ISO isolation layer, the cathode, and the remaining unintentionally doped N-polarity GaN channel layer; Etching away the passivation layer in the central region of the annular structure until the upper surface of the unintentionally doped N-polarity GaN channel layer forms an anode region, and evaporating a plurality of low work function metals that are spaced apart in the anode region; Evaporating a high work function metal on the unintentionally doped N-polarity GaN channel layer, all the low work function metals, and a part of the passivation layer, and the high work function metal has a comb-like structure to form a hybrid anode composed of the high work function metal and a plurality of low work function metals that are spaced apart.

10. The preparation method of the N-polar GaN_AlGaN heterojunction lateral SBD with a mixed metal anode according to claim 9, characterized in that, The preparation method further includes: Etching away a part of the passivation layer on the cathode to form a cathode opening region.

Images