A high-performance vertical GaN-based alpha particle detector and its preparation method

Abstract

The present application provides a high-performance vertical GaN-based alpha particle detector and a preparation method thereof, comprising a stacked second contact electrode, a GaN substrate, a GaN epitaxial layer, a first contact electrode, a guard ring and a passivation layer. By setting the GaN substrate as a heavily Si-doped GaN substrate, the GaN epitaxial layer as a lightly Si-doped GaN epitaxial layer, optimizing the thickness of the first contact electrode, and designing a guard ring, the key performance indicators of the alpha particle detector in terms of sensitivity, charge collection efficiency, energy resolution, response speed and long-term reliability are improved, providing reliable technical support and broad application prospects for the practical application of high-performance GaN-based alpha particle detectors.

Description

Technical Field

[0001] The present application relates to the technical field of alpha particle detection, and in particular to a high-performance vertical GaN-based alpha particle detector and a preparation method thereof. Background Art

[0002] Alpha particles are radioactive particles that are widely used in nuclear radiation detection, nuclear safety monitoring, and environmental radiation detection. As the core component of the alpha particle detection system, the performance of the alpha particle detector directly affects the sensitivity, energy resolution, and reliability of the detection system. Traditional alpha particle detectors mainly use high-purity silicon materials, such as lithium drift silicon, ion implanted silicon, and gold silicon surface barrier detectors. Lithium drift silicon and ion implanted silicon detectors achieve energy collection and signal conversion of alpha particles through the PN junction of silicon, while gold silicon surface barrier detectors rely on Schottky surface barriers to accomplish the same function. However, with the increasing complexity of the application environment, especially under extreme conditions such as strong radiation and high temperature, silicon-based detectors have exposed a variety of problems, such as poor radiation resistance, high temperature performance degradation, and insufficient signal stability.

[0003] In order to overcome the limitations of traditional alpha particle detectors, gallium nitride (GaN) materials have gradually become an ideal choice for the new generation of high-performance alpha particle detector materials due to their wide bandgap (3.4 eV), high breakdown electric field (3 MV / cm), excellent radiation resistance and good thermal stability. However, in the process of alpha particle detection, the existing GaN-based alpha particle detectors have the problems of the energy of the incident alpha particles cannot be effectively converted into electron-hole pairs, and the GaN structure has insufficient charge binding ability, resulting in high charge recombination rate and low charge collection efficiency. Summary of the invention

[0004] The present application aims to solve one of the technical problems in the related art at least to some extent.

[0005] To this end, the first purpose of this application is to propose a high-performance vertical GaN-based α-particle detector and its preparation method, which can further improve the detection sensitivity, energy resolution and response speed of the detector α particles, and also have strong environmental adaptability and long-term reliability.

[0006] To achieve the above objectives, the first embodiment of the present application proposes a high-performance vertical GaN-based α-particle detector, comprising:

[0007] GaN substrate, wherein the GaN substrate is a heavily Si-doped GaN substrate;

[0008] A GaN epitaxial layer is formed on the GaN substrate, wherein the GaN epitaxial layer is a lightly Si-doped GaN epitaxial layer;

[0009] A contact electrode connected to an external circuit; the contact electrode comprises a first contact electrode and a second contact electrode, the first contact electrode is formed on the GaN epitaxial layer, and the second contact electrode is formed on a side of the GaN substrate away from the GaN epitaxial layer;

[0010] A passivation layer is formed on the GaN epitaxial layer and covers the surface of the GaN epitaxial layer exposed around the first contact electrode.

[0011] Optionally, the first contact electrode includes a first contact portion and a second contact portion, the first contact portion is a metal thin layer formed on the GaN epitaxial layer, the second contact portion is a metal column formed on the first contact portion, and the external circuit is electrically connected to the first contact portion through the second contact portion.

[0012] Optionally, the thickness of the first contact portion ranges from 5 nm to 20 nm, and the thickness of the second contact portion ranges from 50 nm to 500 nm.

[0013] Optionally, the doping concentration of the lightly doped Si element in the GaN epitaxial layer ranges from 1 10 14 cm -3 ~ 5 10 15 cm -3 between.

[0014] Optionally, the doping concentration of the heavily doped Si element in the GaN substrate ranges from 1 10 18 cm -3 ~ 1 10 20 cm -3 between.

[0015] Optionally, the α-particle detector further includes a plurality of guard rings spaced apart from each other, wherein the plurality of guard rings are arranged in a ring shape around the periphery of the first contact electrode and extend through the passivation layer to contact the GaN epitaxial layer.

[0016] Optionally, the number of the plurality of mutually spaced protection rings is between 1 and 5.

[0017] Optionally, the material of the contact electrode includes at least one or more alloys of Ti, Hf, Al, Ni, Mo, Pd, Au, and Ag.

[0018] Optionally, the thickness of the GaN epitaxial layer ranges from 10 μm to 30 μm.

[0019] To achieve the above-mentioned purpose, the first embodiment of the present application proposes a method for preparing a high-performance vertical GaN-based α-particle detector, which is used to prepare the α-particle detector described in any of the above embodiments, comprising:

[0020] Providing a GaN substrate, wherein the GaN substrate is a heavily Si-doped GaN substrate;

[0021] Forming a GaN epitaxial layer on the GaN substrate, wherein the GaN epitaxial layer is a lightly Si-doped GaN epitaxial layer;

[0022] forming a second contact electrode on a surface of the GaN substrate away from the GaN epitaxial layer, and forming a first contact electrode and a guard ring on the GaN epitaxial layer, wherein the guard ring is formed around the first contact electrode;

[0023] A passivation layer is formed on the GaN epitaxial layer, wherein the passivation layer covers the surface of the GaN epitaxial layer exposed around the first contact electrode and the guard ring.

[0024] The high-performance vertical GaN-based α-particle detector and its preparation method provided by the present application include at least the following beneficial effects:

[0025] The present application provides a high-performance vertical GaN-based alpha particle detector and a preparation method thereof, comprising a stacked second contact electrode, a GaN substrate, a GaN epitaxial layer, a first contact electrode, a guard ring and a passivation layer. By setting the GaN substrate as a heavily Si-doped GaN substrate, the GaN epitaxial layer as a lightly Si-doped GaN epitaxial layer, optimizing the thickness of the first contact electrode, and designing a guard ring, the key performance indicators of the alpha particle detector in terms of sensitivity, charge collection efficiency, energy resolution, response speed and long-term reliability are improved, providing reliable technical support and broad application prospects for the practical application of high-performance GaN-based alpha particle detectors.

[0026] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0028] Figure 1 Schematic diagram of a top-down structure of a high-performance vertical GaN-based α-particle detector according to an embodiment of the present application.

[0029] Figure 2 Based on Figure 1Schematic diagram of the cross-sectional structure of a high-performance vertical GaN-based α-particle detector taken along the AA' line.

[0030] Figure 3 It is a schematic flow chart of a method for preparing a GaN-based α-particle detector according to an embodiment of the present application.

[0031] 100 GaN substrate; 200 GaN epitaxial layer; 310 first contact electrode; 311 first contact portion; 312 second contact portion; 320 second contact electrode; 400 passivation layer; 500 guard ring. DETAILED DESCRIPTION

[0032] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0033] Alpha particles are common particles produced during the decay of radioactive materials. They are helium nuclei formed by two protons and two neutrons. Alpha particle detectors are widely used in the fields of nuclear radiation detection and nuclear safety monitoring. For example, in nuclear radiation detection, alpha particle detectors are mainly used to identify and quantify the decay signals of radioactive isotopes, especially to monitor radioactive residues during the operation and decommissioning of nuclear facilities. For another example, in nuclear safety monitoring, alpha particle detectors are widely used in environmental radiation monitoring, which can effectively detect and quantify radioactive pollutants in the air, water and soil, and help to timely discover potential radiation risks. By accurately assessing the level of radioactive contamination, alpha particle detectors provide a scientific basis for the formulation of radiation control measures and environmental remediation plans. At the same time, during the transportation, storage and disposal of nuclear materials, alpha particle detectors can monitor the leakage risk of radioactive materials in real time to ensure the safety of nuclear materials and the protection of the surrounding environment. Especially in sensitive areas and scenarios with high safety requirements, high-performance detectors are a core component of the nuclear safety system.

[0034] GaN is a wide bandgap semiconductor material with excellent physical and electrical properties, which makes it show significant advantages in the field of alpha particle detection. First, GaN's wide bandgap (about 3.4 eV) effectively suppresses the dark current generated by thermal excitation, significantly reduces the background noise of the detector, and thus improves the signal-to-noise ratio and sensitivity. Secondly, GaN has a high breakdown electric field (about 3 MV / cm) and can operate under high bias to form a wider depletion region, thereby significantly improving the charge collection efficiency and energy resolution. Thirdly, GaN materials exhibit excellent radiation resistance in radiation environments, can operate stably for a long time, and are not easily degraded by high-energy radiation damage, which makes it particularly suitable for the field of nuclear radiation detection. Finally, GaN materials have excellent physical and chemical stability such as high hardness, corrosion resistance, and high temperature resistance, and can maintain reliable performance in extreme environments.

[0035] Based on the above advantages of GaN materials in α-particle detectors, the present application provides a high-performance vertical GaN-based α-particle detector and a preparation method thereof, which can further meet the high performance requirements of GaN-based α-particle detectors in the α-particle detection process in practical applications.

[0036] The first aspect of the present application provides a high-performance vertical GaN-based α-particle detector, such as Figure 1~Figure 2 As shown, the alpha particle detector includes a GaN substrate 100, a GaN epitaxial layer 200 formed on the GaN substrate 100, a second contact electrode 320 formed on the side of the GaN substrate 100 away from the GaN epitaxial layer 200, and a first contact electrode 310 and a passivation layer 400 formed on the GaN epitaxial layer 200, wherein the passivation layer 400 is formed around the first contact electrode 310 and covers the surface of the GaN epitaxial layer 200 exposed around the first contact electrode 310. The GaN substrate 100 is a heavily Si-doped GaN substrate, and the GaN epitaxial layer 200 is a lightly Si-doped GaN epitaxial layer.

[0037] It can be understood that the α-particle detector provided in the present application is used to detect the incident energy of α-particles in the surrounding environment. When the incident α-particles pass through the first contact electrode 310 and enter the GaN epitaxial layer 200, the α-particles will Coulomb interaction with the shell electrons of the atoms in the GaN epitaxial layer 200 to generate electron-hole pairs. At the same time, the contact electrode composed of the first contact electrode 310 and the second contact electrode 320 can generate an electric field in a vertical direction (in the thickness direction of the GaN substrate 100 and the GaN epitaxial layer 200) between the GaN substrate 100 and the GaN epitaxial layer 200 by connecting to an external circuit, thereby enabling the electrons and holes generated by the α-particle incident in the GaN epitaxial layer 200 to drift in opposite directions under the action of the electric field, and finally generate corresponding electrical signals through the external circuit. Thus, the incident energy of the α-particles in the environment can be calculated by receiving the electrical signal.

[0038] As an example, the positive electrode of the external circuit is electrically connected to the second contact electrode 320, and the negative electrode of the external circuit is electrically connected to the first contact electrode 310, thereby generating a vertical direction from the GaN substrate 100 to the GaN epitaxial layer 200 between the GaN substrate 100 and the GaN epitaxial layer 200, thereby causing the electrons generated by the incident α particles in the GaN epitaxial layer 200 to drift in a direction toward the second contact electrode 320 under the action of the electric field, and at the same time, causing the holes generated by the incident α particles in the GaN epitaxial layer 200 to drift in a direction toward the first contact electrode 310 under the action of the electric field.

[0039] Since the carrier concentration in the GaN epitaxial layer 200 directly affects the width of the depletion region, and the higher carrier concentration in the GaN epitaxial layer 200 will limit the width of the depletion region, thereby reducing the collection efficiency and detection sensitivity of the charges (electrons and holes) generated by the α-particle incident. Therefore, the present application sets the GaN epitaxial layer 200 as a lightly Si-doped GaN epitaxial layer, uses the GaN epitaxial layer 200 to lightly dope the Si element, and reduces the carrier concentration in the GaN epitaxial layer 200, which provides an important condition for achieving a larger depletion region. A large depletion region can not only significantly enhance the collection efficiency of the α-particle detector for the charges generated by α-particles, but also effectively reduce charge recombination and signal loss, thereby improving the energy collection efficiency and energy resolution of the GaN-based α-particle detector. At the same time, the lower carrier concentration in the GaN epitaxial layer 200 can also reduce parasitic capacitance, further improve the response speed of the detector, effectively reduce the background noise, improve the signal quality, and thus improve the overall performance of the detector.

[0040] As an example, the thickness of the GaN epitaxial layer 200 is in the range of 10 μm to 30 μm, and the doping concentration of the lightly doped Si element in the GaN epitaxial layer 200 is in the range of 1 10 14 cm -3 ~ 5 10 15 cm -3 In this example, the thickness of the GaN epitaxial layer 200 is 20 μm, and the doping concentration of the lightly doped Si element inside the GaN epitaxial layer 200 is 6 10 14 cm -3 .

[0041] Since metal electrodes and GaN materials generally have high contact resistance, high contact resistance will cause large voltage loss in the transmission process of electrical signals, reduce the integrity and stability of the signal, and high contact resistance will also increase the power consumption of the α-particle detector due to thermal effects, thereby affecting the reliability of the long-term operation of the α-particle detector. Therefore, the present application sets the GaN substrate 100 as a heavily Si-doped GaN substrate, and uses the heavily doped Si element of the GaN substrate 100 to reduce the resistivity of the GaN substrate 100, thereby providing key support for reducing the contact resistance between the second contact electrode 320 and the GaN substrate 100. The reduction of the contact resistance between the second contact electrode 320 and the GaN substrate 100 can reduce the voltage loss caused by resistance during signal transmission, thereby improving the transmission efficiency and integrity of the signal. This optimized design can not only effectively reduce the power consumption and thermal effects of the α-particle detector, but also significantly enhance the sensitivity and response speed of the α-particle detector, ultimately laying the foundation for achieving high-performance detection.

[0042] As an example, the doping concentration of the heavily doped Si element in the GaN substrate 100 ranges from 1 10 18 cm -3 ~ 1 10 20 cm -3 In this example, the doping concentration of the lightly doped Si element in the GaN substrate 100 is 1 10 19 cm -3 .

[0043] In addition, by performing a rapid high-temperature annealing process on the second contact electrode 320 during the formation process, the contact resistance between the second contact electrode 320 and the GaN substrate 100 can be further optimized, and the conductive contact characteristics between the second contact electrode 320 and the GaN substrate 100 can be improved, so that the second contact electrode 320 becomes a low contact resistance electrode. This process optimization can significantly reduce the resistance loss of the α-particle detector, improve the stability of signal transmission, and further enhance the performance of the α-particle detector. In other words, the present application can provide a reliable guarantee for realizing a high-performance GaN-based α-particle detector with high sensitivity and high reliability by combining a heavily Si-doped GaN substrate 100 with an optimized second contact electrode 320.

[0044] In some embodiments, the first contact electrode 310 may specifically include a first contact portion 311 and a second contact portion 312. The first contact portion 311 is a metal thin layer formed on the GaN epitaxial layer 200 to realize a thin barrier contact electrode. The second contact portion 312 is a metal column formed on the first contact portion 311, which is equivalent to a conductive column, so that an external circuit can be bonded to an end of the second contact portion 312 away from the first contact portion 311 to electrically connect the first contact portion 311 to the external circuit.

[0045] The thickness design of the first contact portion 311 has a significant impact on the performance of the alpha particle detector, and an overly thick first contact electrode 310 will cause significant energy loss when the alpha particles pass through the area, forming a detection dead zone, thereby reducing the charge collection efficiency and causing the energy spectrum to be broadened, thereby reducing the sensitivity and energy resolution of the alpha particle detector. Therefore, the present application designs the first contact electrode 310 to be a metal thin layer first contact portion 311 and a metal columnar second contact portion 312, and uses the first contact portion 311 with a thin thickness and a large area to cover the GaN epitaxial layer 200, so as to significantly reduce the energy loss when the alpha particles are incident and pass through the first contact portion 311, and at the same time reduce the broadening of the alpha particle energy spectrum, thereby improving the sensitivity and energy resolution of the alpha particle detector.

[0046] At the same time, due to the limited thickness of the first contact portion 311, its mechanical strength is insufficient and it is difficult to directly withstand the pressure of gold wire bonding when the external circuit is electrically connected, thereby affecting the structural integrity of the α particle detector. Therefore, the present application also locally deposits a second contact portion 312 with a larger thickness and a smaller area on the first contact portion 311 to enhance the mechanical strength and bonding reliability of the corresponding area of ​​the first contact electrode 310, so that the external circuit can achieve stable gold wire bonding through the second contact portion 312, thereby enabling the first contact electrode 310 provided by the present application to meet the high performance and reliability advantages of the α particle detector, while also ensuring the structural integrity of the α particle detector.

[0047] As an example, the thickness of the first contact portion 311 ranges from 5 nm to 20 nm, the thickness of the second contact portion 312 ranges from 50 nm to 500 nm, and the area ratio between the second contact portion 312 and the first contact portion 311 on the GaN epitaxial layer 200 should be less than 5%. The second contact portion 312 with a smaller area can also reduce the energy loss of alpha particles when passing through the corresponding range of the second contact portion 312. In this example, the thickness of the first contact portion 311 is 20 nm, and the thickness of the second contact portion 312 is 100 nm.

[0048] As an example, the material of the first contact electrode 310 and the second contact electrode 320 includes, but is not limited to, an alloy of at least one or more of Ti, Hf, Al, Ni, Mo, Pd, Au, and Ag.

[0049] It should be noted that, since the second contact electrode 320 is formed on the side of the GaN substrate 100 away from the GaN epitaxial layer 200, the thickness of the second contact electrode 320 will not substantially affect the incident energy of the alpha particles. Therefore, the present application does not specifically limit the second contact electrode 320. In this example, the second contact electrode 320 is 220 nm.

[0050] In some embodiments, the α particle detector in the above embodiment may further include a plurality of mutually spaced guard rings 500 , which are arranged in a ring shape around the first contact electrode 310 and extend through the passivation layer 400 to contact the GaN epitaxial layer 200 .

[0051] Since the electric field between the GaN epitaxial layer 200 and the GaN substrate 100 is usually concentrated in the edge regions of the GaN epitaxial layer 200 and the GaN substrate 100, an electric field concentration effect occurs, which increases the edge leakage current of the device and reduces the breakdown voltage. Therefore, the present application arranges a plurality of protective rings 500 in a rotating manner around the periphery of the first contact electrode 310, and uses the protective rings 500 to adjust the electric field distribution in the edge region outside the first contact electrode 310, thereby successively slowing down or suppressing the electric field concentration effect.

[0052] As an example, the number of the plurality of mutually spaced protection rings 500 is between 1 and 5. In this example, the plurality of protection rings 500 are three protection rings 500 that are coaxial and spaced apart in the radial direction.

[0053] It should be noted that the present application does not impose any specific limitation on the specific material of the guard ring 500 , which may be the same metal material as the contact electrode, or GaN or AlGaN highly doped with metal elements such as Al and Mg.

[0054] In some embodiments, the passivation layer 400 is formed on the GaN epitaxial layer 200 and covers the surface of the GaN epitaxial layer 200 exposed around the first contact electrode 310 to protect the surface of the GaN epitaxial layer 200 circuit.

[0055] The high density of surface states and interface trap states of the GaN epitaxial layer 200 also has an adverse effect on the performance of the detector. Among them, the surface state will cause a significant increase in the surface leakage current, while the interface trap state will capture carriers, affecting the effective collection of charges and reducing the stability of the signal. In addition, external environments such as humidity and pollution will further aggravate the surface state and interface trap state density of the GaN epitaxial layer 200 material, weakening the anti-interference ability of the α particle detector. Therefore, the use of the passivation layer 400 can improve the interface characteristics and environmental stability of the surface of the GaN epitaxial layer 200, and improve the anti-interference ability of the α particle detector.

[0056] At the same time, the guard ring 500 and the passivation layer 400 work together to effectively improve the breakdown voltage of the alpha particle detector, reduce the reverse leakage current, and improve the electrical characteristics, thereby enhancing the long-term reliability of the alpha particle detector.

[0057] As an example, the material of the passivation layer 400 includes but is not limited to a combination of at least one or more of Al2O3, HfO2, Si3N4, TiO2, and ZrO2.

[0058] The second aspect of the present application provides a method for preparing a high-performance vertical GaN-based α-particle detector, which is used to prepare the α-particle detector described in any of the above embodiments. Figure 1~Figure 3 As shown, the method comprises the following steps:

[0059] S1, providing a GaN substrate 100, wherein the GaN substrate 100 is a heavily Si-doped GaN substrate.

[0060] S2, forming a GaN epitaxial layer 200 on the GaN substrate 100, wherein the GaN epitaxial layer 200 is a lightly Si-doped GaN epitaxial layer.

[0061] S3, forming a second contact electrode 320 on the surface of the GaN substrate 100 away from the GaN epitaxial layer 200, and forming a first contact electrode 310 and a guard ring 500 on the GaN epitaxial layer 200, wherein the guard ring 500 is formed around the first contact electrode 310;

[0062] S4 , forming a passivation layer 400 on the GaN epitaxial layer 200 , wherein the passivation layer 400 covers the surface of the GaN epitaxial layer 200 exposed around the first contact electrode 310 and the guard ring 500 .

[0063] In step S1, the GaN substrate 100 is heavily doped with Si to form a doping concentration ranging from 1 10 18 cm -3 ~ 1 10 20 cm -3 between.

[0064] In step S2, the doping concentration of the lightly doped Si element in the GaN epitaxial layer 200 is in the range of 1 10 14 cm -3 ~ 5 10 15 cm -3 The thickness of the GaN epitaxial layer 200 is between 10 μm and 30 μm. Before step S2, the method further includes pre-treating the GaN substrate 100 to reduce the internal defect density of the GaN epitaxial layer 200 and ensure the epitaxial quality of the GaN epitaxial layer 200.

[0065] In step S3 , the second contact electrode 320 formed on the surface of the GaN substrate 100 away from the GaN epitaxial layer 200 is a low contact resistance electrode deposited by MOCVD, and then formed by a rapid high temperature annealing process.

[0066] In addition, the steps of forming the first contact electrode 310 and the guard ring 500 on the GaN epitaxial layer 200 are to deposit a metal thin layer on the GaN epitaxial layer 200 by a metal organic chemical vapor deposition (MOCVD) method, and then dry or wet etch the metal thin layer in a plurality of central coaxial circular ring patterns until the metal thin layer is penetrated and the surface of the GaN epitaxial layer 200 covered by the metal thin layer is exposed, thereby etching the metal thin layer into a disk-shaped first contact portion 311 located in the center and a plurality of guard rings 500 arranged in sequence along the radial direction, and finally locally thickening the first contact portion 311 at a preset position by a local deposition method to form a metal columnar second contact portion 312.

[0067] The GaN epitaxial layer 200 may be formed by any one or more methods including but not limited to molecular beam epitaxy (MBE) or metal organic chemical vapor deposition (MOCVD). The passivation layer 400 may be formed by any one or more methods including but not limited to plasma enhanced chemical vapor deposition (PECVD) or atomic layer deposition (ALD).

[0068] It should be noted that the guard ring 500 in this embodiment is made of the same metal material as the first contact electrode 310. In other embodiments, the guard ring 500 may also be made of materials such as GaN or AlGaN that are highly doped with metal elements such as Al and Mg. In addition, in other embodiments, while forming the second contact portion 312 on the first contact portion 311 by local deposition, the thickness of the guard ring 500 may also be increased simultaneously.

[0069] In step S4 , the passivation layer 400 formed on the GaN epitaxial layer 200 is used to passivate and protect the surface of the GaN epitaxial layer 200 exposed around the first contact electrode 310 and the guard ring 500 .

[0070] In summary, the present application provides a high-performance vertical GaN-based α-particle detector and a preparation method thereof, comprising a stacked second contact electrode 320, a GaN substrate 100, a GaN epitaxial layer 200, a first contact electrode 310, a guard ring 500, and a passivation layer 400. By setting the GaN substrate 100 as a heavily Si-doped GaN substrate, the GaN epitaxial layer 200 as a lightly Si-doped GaN epitaxial layer, optimizing the thickness of the first contact electrode 310, and designing the guard ring 500, the key performance indicators of the α-particle detector in terms of sensitivity, charge collection efficiency, energy resolution, response speed, and long-term reliability are improved, providing reliable technical support and broad application prospects for the practical application of high-performance GaN-based α-particle detectors.

[0071] In the description of the aforementioned embodiments, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they contradict each other.

[0072] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

Claims

1. A high-performance vertical GaN-based α-particle detector for detecting α-particles, characterized in that: include: GaN substrate, wherein the GaN substrate is a heavily Si-doped GaN substrate; A GaN epitaxial layer is formed on the GaN substrate, wherein the GaN epitaxial layer is a lightly Si-doped GaN epitaxial layer; A contact electrode connected to an external circuit; the contact electrode comprises a first contact electrode and a second contact electrode, the first contact electrode is formed on the GaN epitaxial layer, and the second contact electrode is formed on a side of the GaN substrate away from the GaN epitaxial layer; a passivation layer formed on the GaN epitaxial layer and covering the surface of the GaN epitaxial layer exposed around the first contact electrode; The first contact electrode includes a first contact portion and a second contact portion, the first contact portion is a metal thin layer formed on the GaN epitaxial layer, the second contact portion is a metal column formed on the first contact portion, and the external circuit is electrically connected to the first contact portion through the second contact portion.

2. The alpha particle detector according to claim 1, characterized in that The thickness of the first contact portion ranges from 5 nm to 20 nm, and the thickness of the second contact portion ranges from 50 nm to 500 nm.

3. The alpha particle detector according to claim 1, characterized in that The doping concentration of the lightly doped Si element in the GaN epitaxial layer ranges from 1 10 14 cm -3 ~ 5 10 15 cm -3 between.

4. The alpha particle detector according to claim 1, characterized in that The doping concentration of the heavily doped Si element in the GaN substrate ranges from 1 10 18 cm -3 ~ 1 10 20 cm -3 between.

5. The alpha particle detector according to claim 1, characterized in that: The alpha particle detector further includes a plurality of mutually spaced guard rings, which are arranged in a ring shape around the periphery of the first contact electrode and extend through the passivation layer to contact the GaN epitaxial layer.

6. The alpha particle detector according to claim 5, characterized in that: The number of the plurality of mutually spaced protection rings is between 1 and 5.

7. The alpha particle detector according to claim 1, characterized in that: The material of the contact electrode includes at least one or more alloys of Ti, Hf, Al, Ni, Mo, Pd, Au, and Ag.

8. The alpha particle detector according to claim 1, characterized in that The thickness of the GaN epitaxial layer ranges from 10 μm to 30 μm.

9. A method for preparing a high-performance vertical GaN-based α-particle detector, used for preparing the α-particle detector according to any one of claims 1 to 8, characterized in that: include: Providing a GaN substrate, wherein the GaN substrate is a heavily Si-doped GaN substrate; Forming a GaN epitaxial layer on the GaN substrate, wherein the GaN epitaxial layer is a lightly Si-doped GaN epitaxial layer; forming a second contact electrode on a surface of the GaN substrate away from the GaN epitaxial layer, and forming a first contact electrode and a guard ring on the GaN epitaxial layer, wherein the guard ring is formed around the first contact electrode; A passivation layer is formed on the GaN epitaxial layer, wherein the passivation layer covers the surface of the GaN epitaxial layer exposed around the first contact electrode and the guard ring.

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