Silicon carbide micro-dose detector, preparation method and microdosimetric parameter acquisition method

Abstract

A silicon carbide micro-dose detector, its fabrication method, and a method for acquiring micro-dosimetric parameters are disclosed. The micro-dose detector comprises: a back electrode layer connected to a high-voltage potential of an external bias voltage; an N-type heavily doped silicon carbide layer disposed on the back electrode layer; an intrinsic sensitive layer, in a first preset structure, disposed on the N-type heavily doped silicon carbide layer, which is an N-type lightly doped silicon carbide layer, constituting a sensitive element for micro-dose measurement; a P-type heavily doped silicon carbide layer, in a second preset structure, disposed on the intrinsic sensitive layer; and a front electrode layer connected to a reference potential of the external bias voltage, disposed on the P-type heavily doped silicon carbide layer. The method for acquiring micro-dosimetric parameters includes: conditioning and converting the transient current signal output from the front electrode layer to obtain a voltage pulse signal; determining the single deposition energy based on the pulse amplitude; calculating the linear energy value by combining the average chord length of the sensitive volume; and obtaining the linear energy distribution and corresponding micro-dosimetric parameters based on statistics of all events.

Description

Technical Field

[0001] This application relates to the field of micro-dose detection technology, specifically to a silicon carbide micro-dose detector, its preparation method, and a method for obtaining micro-dosimetric parameters, for micro-dose detection to characterize the energy deposition behavior of radiation particles at the microscale. Background Technology

[0002] Microdosimetry detection typically uses tissue equivalent proportional counters (TEPCs) to measure energy deposition. While it has certain advantages in terms of tissue equivalence, it generally suffers from problems such as large device size, complex structure, limited spatial resolution, and high dependence on gas supply system and high-pressure bias. While current solid-state microdosimeters based on silicon (Si) materials can achieve high spatial resolution through microstructured sensing units, the inventors of this application have discovered that silicon materials are prone to radiation-induced defects under high temperature, long-term irradiation, and high dose rate conditions. This leads to increased reverse leakage current and decreased charge collection efficiency, resulting in increased noise and degraded energy spectrum resolution, affecting the stability and repeatability of measurement results.

[0003] The content of the background section is merely technology known to the public and does not necessarily represent existing technology in the field. Summary of the Invention

[0004] According to one aspect of this application, a silicon carbide micro-dose detector is provided, which may include a back electrode layer, an N-type heavily doped silicon carbide layer, an intrinsically sensitive layer, a P-type heavily doped silicon carbide layer, and a front electrode layer. The back electrode layer is connected to a high-voltage potential of an external bias voltage; an N-type heavily doped silicon carbide layer is disposed on the back electrode layer; an intrinsic sensitive layer is disposed on the N-type heavily doped silicon carbide layer with a first preset structure, which is an N-type lightly doped silicon carbide layer, constituting a sensor for micro-dose measurement, wherein the first preset structure is cylindrical, prismatic, or nearly spherical; a P-type heavily doped silicon carbide layer is disposed on the intrinsic sensitive layer with a second preset structure, wherein the cross-section of the second preset structure is the same as the cross-section of the first preset structure; the front electrode layer is connected to a reference potential of an external bias voltage, and the front electrode layer is disposed on the P-type heavily doped silicon carbide layer; the N-type heavily doped silicon carbide layer, the intrinsic sensitive layer, and the P-type heavily doped silicon carbide layer form a PIN junction structure, which has a built-in electric field; when radiating particles are incident on the sensor, energy is deposited in the sensor and electron-hole pairs are generated. Under the action of the built-in electric field and the external bias voltage, the electron-hole pairs are collected and converted into electrical signals, and the front electrode layer outputs a transient current signal.

[0005] According to some embodiments of this application, the material of the front electrode layer is one or more of aluminum, nickel, titanium, gold, platinum, their alloys, and a multilayer composite structure formed of aluminum, nickel, titanium, gold, and platinum.

[0006] According to some embodiments of this application, the doping element of the P-type heavily doped silicon carbide layer is aluminum, boron, gallium, or a combination thereof, and the doping concentration of the doping element in the P-type heavily doped silicon carbide layer ranges from 1×10⁻⁶. 18 cm -3 ~5×10 19 cm -3 The thickness of the P-type heavily doped silicon carbide layer ranges from 0.2 μm to 2 μm.

[0007] According to some embodiments of this application, the doping element of the intrinsic sensitive layer is nitrogen, phosphorus, or a combination thereof, and the doping concentration of the doping element in the intrinsic sensitive layer ranges from 1×10⁻⁶. 13 cm -3 ~5×10 14 cm -3 The thickness of the intrinsic sensitive layer ranges from 2μm to 10μm.

[0008] According to some embodiments of this application, the doping element of the N-type heavily doped silicon carbide layer is nitrogen, phosphorus, or a combination thereof, and the doping concentration of the doping element in the N-type heavily doped silicon carbide layer ranges from 1 × 10⁻⁶. 18 cm -3 ~1×10 19 cm -3 The thickness of the N-type heavily doped silicon carbide layer ranges from 200 μm to 500 μm.

[0009] According to some embodiments of this application, the material of the back electrode layer is one or more of titanium, nickel, aluminum, gold, molybdenum, their alloys, and multilayer composite structures formed by titanium, nickel, aluminum, gold, and molybdenum.

[0010] According to some embodiments of this application, when the first preset structure is a cylinder, the diameter of the cylinder ranges from 2μm to 30μm, and the height of the cylinder ranges from 2μm to 10μm; when the first preset structure is a prism or a near-sphere, the equivalent lateral feature size of the prism or near-sphere ranges from 2μm to 30μm, and the thickness of the prism or near-sphere ranges from 2μm to 10μm.

[0011] According to some embodiments of this application, multiple sensors are arranged in an array, with adjacent sensors having a preset size. The multiple sensors are connected by a bridge interconnection structure.

[0012] According to one aspect of this application, a method for fabricating a silicon carbide micro-dose detector is provided. The method comprises: fabricating an N-type heavily doped silicon carbide layer on a 4H-SiC single crystal; epitaxially growing an initial intrinsic sensitive layer on a first surface of the N-type heavily doped silicon carbide layer, wherein the initial intrinsic sensitive layer is an N-type lightly doped silicon carbide layer; implanting acceptor dopant elements into a predetermined region on the first surface of the initial intrinsic sensitive layer to form an initial P-type heavily doped silicon carbide layer; etching the initial P-type heavily doped silicon carbide layer and the initial intrinsic sensitive layer to obtain an intrinsic sensitive layer with a first predetermined structure and a P-type heavily doped silicon carbide layer with a second predetermined structure, wherein the first predetermined structure is columnar, prismatic, or near-spherical, and the cross-section of the second predetermined structure is the same as the cross-section of the first predetermined structure; forming a back electrode layer on the second surface of the N-type heavily doped silicon carbide layer; and forming a front electrode layer on the first surface of the P-type heavily doped silicon carbide layer to form a micro-dose detector.

[0013] According to one aspect of this application, a method for obtaining microdosimetry parameters is provided, comprising: receiving a transient current signal output from a microdosimeter as described above corresponding to a single event; determining a voltage pulse signal corresponding to the transient current signal based on the transient current signal; determining the pulse amplitude corresponding to the single event based on the voltage pulse signal; determining the single deposition energy corresponding to the pulse amplitude based on the pulse amplitude; determining the linear energy value of the single event based on the single deposition energy and the average chord length of the sensitive volume; traversing all single events to determine all linear energy values; determining linear energy frequency distribution data based on all linear energy values; and determining microdosimetry parameters based on the linear energy frequency distribution data.

[0014] According to another aspect of this application, this application also provides a non-volatile computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is capable of implementing the microdosimetric parameter acquisition method as described above.

[0015] According to another aspect of this application, this application also provides an electronic device, including: one or more processors; and a storage device for storing one or more programs, which, when executed by one or more processors, enable the one or more processors to implement the microdosimetric parameter acquisition method as described above.

[0016] According to another aspect of this application, this application also provides a computer program product, comprising: a computer program stored on a computer-readable storage medium; the computer program includes program instructions that, when executed by a computer, cause the computer to perform the microdosimetric parameter acquisition method as described above.

[0017] The micro-dose detector of this application comprises, from bottom to top, a back electrode layer, an N-type heavily doped silicon carbide layer, an intrinsic sensitive layer, a P-type heavily doped silicon carbide layer, and a front electrode layer. The back electrode layer is connected to a high-voltage potential of an external bias voltage. The N-type heavily doped silicon carbide layer is disposed on the back electrode layer. The intrinsic sensitive layer, which is a lightly doped N-type silicon carbide layer, is disposed on the N-type heavily doped silicon carbide layer with a first preset structure, constituting a sensitive element for micro-dose measurement. The first preset structure is cylindrical, prismatic, or nearly spherical. The P-type heavily doped silicon carbide layer, which is disposed on the intrinsic sensitive layer with a second preset structure, has the same cross-section as the first preset structure. The front electrode layer is connected to a reference potential of the external bias voltage and is disposed on the P-type heavily doped silicon carbide layer.

[0018] When radiating particles are incident on a sensitive body, energy is deposited within the sensitive body, generating electron-hole pairs. Under the influence of a built-in electric field and an external bias voltage, the electron-hole pairs are collected and converted into electrical signals. The front electrode layer outputs a transient current signal to measure the microscopic energy deposition event.

[0019] The micro-dose detector of this application systematically introduces the third-generation semiconductor SiC into the structure of the micro-dose detector, making full use of the high radiation hardness, wide bandgap characteristics and excellent thermal stability of SiC material. This enables the micro-dose detector to maintain stable electrical performance and response characteristics under high dose rate, long-term continuous irradiation and complex mixed radiation field conditions, effectively suppressing the influence of radiation damage and temperature drift on the measurement results, thereby significantly improving the long-term stability and reliability of the micro-dose detector. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A schematic diagram of the structure of a micro-dose detector according to an embodiment of this application is shown; Figure 2 A three-dimensional structural schematic diagram of a micro-dose detector according to an embodiment of this application is shown; Figure 3 An exploded three-dimensional structural view of a micro-dose detector according to an embodiment of this application is shown. Figure 4 A schematic flowchart of the preparation method 1000 according to an embodiment of this application is shown; Figure 5 A schematic diagram of a PIN junction structure according to an embodiment of this application is shown; Figure 6 This diagram illustrates the etching of an initial p-type heavily doped silicon carbide layer and an initial intrinsic sensitive layer according to an embodiment of this application. Figure 7 This diagram illustrates the fabrication of the back electrode layer according to an embodiment of this application. Figure 8 A schematic diagram of the fabrication of the pre-electrode layer according to an embodiment of this application is shown; Figure 9 A flowchart illustrating a method 2000 according to an embodiment of this application is shown.

[0022] Explanation of reference numerals in the attached figures: 10. Micro-dose detector; 11. Back electrode layer; 12. N-type heavily doped silicon carbide layer; 13. Intrinsic sensitive layer; 14. P-type heavily doped silicon carbide layer; 15. Front electrode layer; 16. Bridge interconnect structure. Detailed Implementation

[0023] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that this application will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted.

[0024] The described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a full understanding of embodiments of this disclosure. However, those skilled in the art will recognize that the technical solutions of this disclosure can be practiced without one or more of these specific details, or other methods, components, materials, devices, etc. In these cases, well-known structures, methods, devices, implementations, materials, or operations will not be shown or described in detail.

[0025] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0026] The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order.

[0027] The technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0028] The English terms used in this application, their full English names, and their corresponding Chinese definitions are as follows: LET, Linear Energy Transfer, refers to linear energy transfer density. TEPC, Tissue Equivalent Proportional Counter; PIN stands for Positive-Intrinsic-Negative. PVT, Physical Vapor Transport, Physical Vapor Transport.

[0029] According to one aspect of this application, a silicon carbide micro-dose detector is provided. See also Figures 1-3 The micro-dose detector 10 may include a back electrode layer 11, an N-type heavily doped silicon carbide layer 12, an intrinsic sensitive layer 13, a P-type heavily doped silicon carbide layer 14, and a front electrode layer 15.

[0030] According to the example embodiment, the back electrode layer 11 is connected to a high-voltage potential of an external bias voltage. The back electrode layer 11 can be a metal electrode layer, and the metal material of the metal electrode layer can be a metal material capable of forming an ohmic contact with the N-type heavily doped silicon carbide layer 12. The thickness of the back electrode layer 11 can be 220 nm. The external bias voltage can be a DC voltage. The high-voltage potential can be the positive terminal of the external bias voltage.

[0031] According to an example embodiment, an N-type heavily doped silicon carbide layer 12 is disposed on the back electrode layer 11. The N-type heavily doped silicon carbide layer 12 can be a semiconductor layer formed by doping a silicon carbide crystal with a pentavalent element, and the doping concentration of the pentavalent element is high.

[0032] According to the example embodiment, the intrinsic sensitive layer 13 is disposed on the N-type heavily doped silicon carbide layer 12 in a first predetermined structure. The first predetermined structure can be a three-dimensional structure of the intrinsic sensitive layer 13, and the first predetermined structure can be a columnar, prismatic, or near-spherical shape. The intrinsic sensitive layer 13 is an N-type lightly doped silicon carbide layer, constituting a sensor for micro-dose measurement. The N-type lightly doped silicon carbide layer can be a semiconductor layer formed by doping a silicon carbide crystal with pentavalent elements, and the doping concentration of the pentavalent elements is low.

[0033] According to the example embodiment, a p-type heavily doped silicon carbide layer 14 is disposed on the intrinsic sensitive layer 13 in a second predetermined structure. The p-type heavily doped silicon carbide layer 14 can be a semiconductor layer formed by doping a silicon carbide crystal with trivalent elements, and the doping concentration of the trivalent elements is high. The second predetermined structure can be a three-dimensional structure of the p-type heavily doped silicon carbide layer 14. The cross-section of the second predetermined structure is the same as the cross-section of the first predetermined structure. For example, the p-type heavily doped silicon carbide layer 14 and the intrinsic sensitive layer 13 can be fabricated in the same photolithography step.

[0034] According to the example embodiment, the front electrode layer 15 is connected to a reference potential of an external bias voltage, and the front electrode layer 15 is disposed on a p-type heavily doped silicon carbide layer 14. The front electrode layer 15 can be a metal electrode layer, and the metal material of the metal electrode layer can be a metal material capable of forming an ohmic contact with the p-type heavily doped silicon carbide layer 14. The thickness of the front electrode layer 15 can be 200 nm. The reference potential can be the negative terminal of the external bias voltage or the ground terminal.

[0035] The N-type heavily doped silicon carbide layer 12, the intrinsic sensitive layer 13, and the P-type heavily doped silicon carbide layer 14 form a PIN junction structure, which has a built-in electric field. During operation, the P-type heavily doped silicon carbide layer 14 and the intrinsic sensitive layer 13 (the N-type lightly doped silicon carbide layer) form a PN junction structure. Within the PN junction structure, the diffusion of charge carriers (electron-hole) creates a space charge region, thereby generating a built-in electric field pointing from the N-region to the P-region. Without an applied external bias voltage, this built-in electric field exists only in a depletion region of limited width. The depletion layer is relatively thin and cannot cover the entire intrinsic sensitive layer 13. Charge carriers in the neutral region mainly move by diffusion, making recombination easy and resulting in low charge collection efficiency.

[0036] The back electrode layer 11 is connected to the high-voltage potential of the external bias voltage, and the front electrode layer 15 is connected to the reference potential of the external bias voltage, thereby applying a reverse bias voltage between the P-type heavily doped silicon carbide layer 14 and the N-type heavily doped silicon carbide layer 12. When the external bias voltage applies a reverse bias to the micro-dose detector 10, the direction of the applied electric field is consistent with the built-in electric field, causing the depletion region to extend towards the intrinsic sensitive layer 13 and achieve complete depletion, thereby establishing a stable electric field distribution throughout the entire intrinsic sensitive layer 13.

[0037] When radiated particles are incident on the sensitive body, energy is deposited within the sensitive body and electron-hole pairs are generated. Under the action of the built-in electric field and the external bias voltage, the electron-hole pairs are collected and converted into electrical signals. The front electrode layer 15 outputs a transient current signal to measure the microscopic energy deposition event.

[0038] For example, the radiated ions can be charged particles, or high-LET particles generated from uncharged particles after passing through the conversion layer. The conversion layer can be a material layer disposed on the surface of the front electrode layer 15, which allows uncharged particles to generate high-energy electrons. For example, the radiated ions can be alpha particles (helium nuclei, carrying two positive charges), beta particles (electrons or positrons, carrying one negative or positive charge), protons, heavy ions, neutrons, gamma rays (photons), X-rays, etc. The material of the conversion layer can be... 10 B or 6 LiF, etc., are set according to the type of uncharged particles, and this application does not impose any restrictions.

[0039] When radiated particles are incident on the sensitive body, electron-hole pairs are generated during the energy deposition process within the sensitive body. Under the influence of the built-in electric field and the external bias voltage, electrons drift towards the N-type heavily doped silicon carbide layer 12 and are eventually collected by the back electrode layer 11, while holes drift towards the P-type heavily doped silicon carbide layer 14 and are collected by the front electrode layer 15. During the drift process, electrons and holes induce transient current signals on the corresponding electrode layers, which are then output by the front electrode layer 15.

[0040] The transient current signal is converted into a voltage pulse signal by a subsequent external circuit (such as a preamplifier, and then processed by a subsequent data acquisition circuit to extract micro-dosimetric parameters) to achieve the measurement and recording of a single energy deposition event.

[0041] Through the above embodiments, the micro-dose detector of this application, from bottom to top, includes a back electrode layer, an N-type heavily doped silicon carbide layer, an intrinsic sensitive layer, a P-type heavily doped silicon carbide layer, and a front electrode layer. The back electrode layer is connected to a high-voltage potential of an external bias voltage. The N-type heavily doped silicon carbide layer is disposed on the back electrode layer. The intrinsic sensitive layer is disposed on the N-type heavily doped silicon carbide layer with a first preset structure. The intrinsic sensitive layer is an N-type lightly doped silicon carbide layer, constituting a sensitive element for micro-dose measurement. The first preset structure is cylindrical, prismatic, or nearly spherical. The P-type heavily doped silicon carbide layer is disposed on the intrinsic sensitive layer with a second preset structure. The cross-section of the second preset structure is the same as the cross-section of the first preset structure. The front electrode layer is connected to a reference potential of an external bias voltage and is disposed on the P-type heavily doped silicon carbide layer.

[0042] When radiating particles are incident on a sensitive body, energy is deposited within the sensitive body, generating electron-hole pairs. Under the influence of a built-in electric field and an external bias voltage, the electron-hole pairs are collected and converted into electrical signals. The front electrode layer outputs a transient current signal to measure the microscopic energy deposition event.

[0043] The micro-dose detector of this application systematically introduces the third-generation semiconductor SiC into the structure of the micro-dose detector, making full use of the high radiation hardness, wide bandgap characteristics and excellent thermal stability of SiC material. This enables the micro-dose detector to maintain stable electrical performance and response characteristics under high dose rate, long-term continuous irradiation and complex mixed radiation field conditions, effectively suppressing the influence of radiation damage and temperature drift on the measurement results, thereby significantly improving the long-term stability and reliability of the micro-dose detector.

[0044] The micro-dose detector of this application employs a PIN-type semiconductor structure. By introducing an intrinsic sensitive layer of N-type lightly doped silicon carbide between a P-type heavily doped silicon carbide layer and an N-type heavily doped silicon carbide layer, the energy deposited by radiation particles in the microstructure can be efficiently converted into electron-hole pairs and rapidly and completely collected under the action of a built-in electric field and an external bias voltage, thereby achieving accurate characterization of single energy deposition events. The PIN junction structure can effectively reduce carrier recombination and charge loss, improving signal collection efficiency.

[0045] Optionally, the material of the front electrode layer 15 is one or more of aluminum, nickel, titanium, gold, platinum, their alloys (alloys composed of aluminum, nickel, titanium, gold, and platinum), and a multilayer composite structure formed by aluminum, nickel, titanium, gold, and platinum.

[0046] Optionally, the doping element of the p-type heavily doped silicon carbide layer 14 is aluminum, boron, gallium, or a combination thereof, and the doping concentration of the doping element in the p-type heavily doped silicon carbide layer 14 ranges from 1 × 10⁻⁶. 18 cm -3 ~5×10 19 cm -3 The thickness of the p-type heavily doped silicon carbide layer 14 ranges from 0.2 μm to 2 μm. The p-type heavily doped silicon carbide layer 14 is used to form a PN junction structure with the intrinsic sensitive layer 13 and establish a stable built-in electric field.

[0047] Optionally, the doping element of the intrinsic sensitive layer 13 is nitrogen, phosphorus, or a combination thereof, and the doping concentration of the doping element in the intrinsic sensitive layer 13 ranges from 1 × 10⁻⁶. 13 cm -3 ~5×10 14 cm -3 The thickness of the intrinsic sensitive layer 13 ranges from 2 μm to 10 μm.

[0048] Optionally, the doping element of the N-type heavily doped silicon carbide layer 12 is nitrogen, phosphorus, or a combination thereof, and the doping concentration of the doping element in the N-type heavily doped silicon carbide layer 12 ranges from 1 × 10⁻⁶. 18 cm -3 ~1×10 19 cm -3The thickness of the N-type heavily doped silicon carbide layer 12 ranges from 200 μm to 500 μm. The N-type heavily doped silicon carbide layer 12 is used to provide mechanical support and form a low-resistance current transmission channel.

[0049] Optionally, the material of the back electrode layer 11 is one or more of titanium, nickel, aluminum, gold, molybdenum, their alloys (alloys of titanium, nickel, aluminum, gold, and molybdenum), and multilayer composite structures formed by titanium, nickel, aluminum, gold, and molybdenum.

[0050] Optionally, when the first preset structure is a cylinder, the diameter of the cylinder ranges from 2 μm to 30 μm, and the height of the cylinder ranges from 2 μm to 10 μm. This geometry is in the micrometer range, close to the characteristic scale of a typical cell or cell nucleus, and can effectively simulate the energy deposition process of radiating particles within a microscopic volume. For example, the diameter of the cylinder is approximately 10 μm, and the height is approximately 3.5 μm.

[0051] When the first preset structure is prismatic or near-spherical, the equivalent lateral feature size of the prismatic or near-spherical structure ranges from 2μm to 30μm, and the thickness ranges from 2μm to 10μm.

[0052] The micro-dose detector of this application designs a single sensitive volume with a diameter and height comparable to the cellular scale, enabling the micro-dose detector to more realistically simulate the energy deposition process of radiation particles at the cellular and subcellular scales.

[0053] Optionally, multiple micro-dose detectors 10 as described above can be integrated into a chip. Multiple sensors are arranged in an array, with adjacent sensors having a preset size.

[0054] For example, the preset dimensions may include the center-to-center spacing between adjacent sensors. The center-to-center spacing is determined comprehensively based on the lateral dimensions of the sensors (e.g., diameter, equivalent lateral feature size), the width of the cell isolation structure, the metal interconnect wiring requirements, and the electrical crosstalk control requirements of adjacent cells, in order to reduce charge crosstalk while ensuring array integration density. For example, the center-to-center spacing can be 20 μm.

[0055] Optionally, see Figures 2-3 Multiple sensitive elements are connected via a bridge interconnect structure 16 to a common front electrode layer 15, enabling array-based shared signal acquisition. The technical solution of this application significantly improves the effective detection area and event statistics by integrating multiple sensitive volumes in a regular array onto the same chip, which is beneficial for obtaining statistically significant microdosimetric distribution data, thereby improving the reliability of radiation biological effect assessment.

[0056] According to one aspect of this application, this application provides a method 1000 for fabricating a silicon carbide micro-dose detector, the method 1000 being used to fabricate the micro-dose detector as described above. See also Figure 4 The preparation method 1000 includes steps S110-S160.

[0057] In step S110, an N-type heavily doped silicon carbide layer is prepared on a 4H-SiC single crystal.

[0058] According to the example embodiment, 4H-SiC single crystal material is grown using silicon (Si) and carbon (C) raw materials. A low-resistivity N-type heavily doped silicon carbide single crystal substrate (i.e., N-type heavily doped silicon carbide layer 12) is then formed on the 4H-SiC single crystal using physical vapor transport (PVT). For example, the thickness of the N-type heavily doped silicon carbide layer 12 is approximately 350 μm, and the dopant element is nitrogen, with a nitrogen doping concentration of approximately 1 × 10⁻⁶. 18 cm -3 The N-type heavily doped silicon carbide layer 12 is used to provide good mechanical support and a low-resistance current transmission channel.

[0059] In step S120, an initial intrinsic sensitive layer is epitaxially grown on the first surface of the N-type heavily doped silicon carbide layer.

[0060] According to the example embodiment, the initial intrinsic sensitive layer 13 is an N-type lightly doped silicon carbide layer. The first surface can be the upper surface.

[0061] An N-type lightly doped silicon carbide epitaxial layer is grown on the upper surface of the heavily doped N-type silicon carbide layer 12 by chemical vapor deposition, serving as the initial intrinsic sensitive layer 13. The thickness and doping concentration of the initial intrinsic sensitive layer 13 are set according to the micro-dose detection requirements to achieve a fully depleted operating state. For example, the initial intrinsic sensitive layer 13 has a thickness of approximately 3.5 μm, with nitrogen as the donor dopant and a doping concentration of approximately 2 × 10⁻⁶. 14 cm -3 It is the main sensitive volume for the deposition of radiation particle energy and the generation of charge carriers.

[0062] In step S130, acceptor doping elements are implanted in a preset region on the first surface of the initial intrinsic sensitive layer to form an initial P-type heavily doped silicon carbide layer.

[0063] According to the example embodiment, the preset region can be a designated acceptor element doped region on the upper surface of the initial intrinsic sensitive layer 13.

[0064] An acceptor dopant element (such as aluminum) is implanted into a predetermined region on the upper surface of the initial intrinsic sensitive layer 13 via ion implantation, forming an initial P-type heavily doped silicon carbide layer 14. After ion implantation, a high-temperature annealing process is performed to activate the dopant ions and repair lattice damage, thereby forming a PIN junction structure with the initial intrinsic sensitive layer 13 and the N-type lightly doped silicon carbide layer 12, such as... Figure 5 As shown.

[0065] The initial p-type heavily doped silicon carbide layer 14 has a thickness of approximately 0.3 μm, with aluminum as the dominant dopant and a doping concentration of approximately 1 × 10⁻⁶. 19 cm -3 .

[0066] In step S140, the initial P-type heavily doped silicon carbide layer and the initial intrinsic sensitive layer are etched to obtain an intrinsic sensitive layer with a first preset structure and a P-type heavily doped silicon carbide layer with a second preset structure.

[0067] According to the example embodiment, the first preset structure is a column, prism, or near-spherical shape, and the cross-section of the second preset structure is the same as the cross-section of the first preset structure.

[0068] Photolithography was performed on the initial p-type heavily doped silicon carbide layer 14 and the initial intrinsic sensitive layer 13 to define the device region of the micro-dose detector. SiO2 was deposited as a hard mask, and reactive ion etching was used to achieve pattern transfer and mesa etching to complete device isolation, forming the first preset structure of the intrinsic sensitive layer 13, the second preset structure of the p-type heavily doped silicon carbide layer 14, and the isolation structure, as follows. Figure 6 As shown in the figure. Subsequently, an insulating passivation layer was deposited and surface treatment was performed on the wafer to improve the interface stability and environmental reliability of the micro-dose detector.

[0069] In step S150, a back electrode layer is formed on the second surface of the N-type heavily doped silicon carbide layer.

[0070] According to the example embodiment, the second surface can be the lower surface. A back electrode layer is formed on the lower surface of the N-type heavily doped silicon carbide layer 12 using a metal deposition process. For example, Ni is deposited on the lower surface of the N-type heavily doped silicon carbide layer 12, and ohmic back electrode formation is achieved through laser annealing. Ti / Ni metal is deposited as the back electrode layer 11 using a metal deposition process to improve conductivity and welding reliability. The back electrode layer 11 has a thickness of approximately 220 nm. Figure 7 As shown.

[0071] In step S160, a front electrode layer is formed on the first surface of the P-type heavily doped silicon carbide layer to form a micro-dose detector.

[0072] On the upper surface of the p-type heavily doped silicon carbide layer 14, a front electrode layer 15 is formed by metal deposition, and the metal interconnect structure of the front electrode layer 15 is constructed by patterning. For example, on the upper surface of the p-type heavily doped silicon carbide layer 14, Ni is deposited and ohmic back electrode is achieved by laser annealing. Al metal is deposited as the front electrode layer by metal deposition, and the metal interconnect structure of the front electrode layer 11 is constructed by patterning. The front electrode layer 11 has a thickness of approximately 200 nm. Figure 8 As shown.

[0073] Subsequently, the processed chip is cut, packaged, and wire-bonded so that the front electrode layer 15 and the back electrode layer 11 are connected to external electronic systems (such as external bias voltage, preamplifier, shaping circuit, analog-to-digital converter, etc.) to obtain a 4H-SiC PIN micro-dose detector that can be used for electrical signal readout.

[0074] Through the above embodiments, the micro-dose detector of this application can be prepared using existing preparation processes, which are simple and compatible with existing preparation processes.

[0075] According to one aspect of this application, a method 2000 for obtaining microdosimetric parameters is provided. Method 2000 can be executed by a computer system, which can be a host or server with data processing capabilities. See also... Figure 9 Method 2000 may include steps S210-S280.

[0076] In step S210, a transient current signal corresponding to a single event is received from the output of the micro-dose detector as described above.

[0077] According to an example embodiment, a single event can be a single energy deposition event following the incident of radiating particles on the sensitive volume. For example, a computer system can receive transient current signals via a signal connection to the front electrode layer.

[0078] In step S220, the voltage pulse signal corresponding to the transient current signal is determined based on the transient current signal.

[0079] According to an example embodiment, the voltage pulse signal can be a voltage pulse that retains the time-domain and amplitude characteristics of the transient current signal. For example, a computer system can convert a transient current signal into a voltage pulse signal using a preamplifier. The computer system can also filter and shape the voltage pulse signal using a shaping circuit to improve its signal-to-noise ratio.

[0080] In step S230, the pulse amplitude corresponding to a single event is determined based on the voltage pulse signal.

[0081] According to the example embodiment, the pulse amplitude can be the maximum instantaneous value of the voltage pulse signal deviating from its resting state (baseline) on the time axis.

[0082] For example, a computer system can use an analog-to-digital converter to sample and record the amplitude of a voltage pulse signal to obtain the pulse amplitude corresponding to a single event.

[0083] In step S240, the single deposition energy corresponding to the pulse amplitude is determined based on the pulse amplitude.

[0084] According to an example embodiment, the single-pass deposition energy can be the energy deposited by radiating particles within a sensitive volume during a single event. The computer system can convert the pulse amplitude into single-pass deposition energy by establishing a pre-calibrated scale correspondence between the pulse amplitude and the deposition energy.

[0085] For example, a computer system can determine the energy of a single deposition using the following formula:

[0086] Where E is the energy of a single deposition (unit: keV), k is the energy calibration factor, A is the pulse amplitude (or Dow Jones index), and b is the zero-point offset. The calibration factor and zero-point offset are obtained by calibration using a standard radiation source with known energy (e.g., an alpha particle source).

[0087] In step S250, the linear energy value of a single event is determined based on the single deposition energy and the average chord length of the sensitive volume.

[0088] According to an example embodiment, the chord length can be the length of the straight path of a radiating particle traveling within the sensitive volume. The average chord length can be the average length of the straight path of a radiating particle traveling within the sensitive volume.

[0089] The linear energy value can be expressed as the ratio of the energy deposited by the radiating particle within the sensitive volume during a single event (i.e., the energy deposited in a single event) to the average chord length of the sensitive volume. For example, a computer system can determine the linear energy value using the following formula:

[0090] in, The value is the linear energy. For single deposition energy, The average chord length of the sensitive volume.

[0091] In step S260, all single events are traversed to determine all line energy values.

[0092] According to the example embodiment, the computer system can traverse all single events and execute steps S210-S250 for all single events to obtain all line energy values.

[0093] In step S270, the linear energy frequency distribution data is determined based on all the linear energy values.

[0094] According to the example embodiment, the linear energy frequency distribution data can be the probability density of linear energy values ​​falling within a specific interval in all single events. For example, a computer system can perform statistical analysis on all linear energy values ​​to obtain linear energy frequency distribution data (denoted as f(y)).

[0095] In step S280, microdosimetric parameters are determined based on the linear energy frequency distribution data.

[0096] According to an example embodiment, microdosimetry parameters can be statistics that quantify the energy deposition characteristics of radiated particles on a sensitive volume. Microdosimetry parameters may include parameters such as dose distribution and dose-averaged linear energy.

[0097] For example, a computer system can determine the dose distribution using the following formula:

[0098] in, For dose distribution, This is the linear energy frequency distribution data.

[0099] For example, a computer system can determine the dose-average linear energy using the following formula:

[0100] in, This represents the dose-average linear energy.

[0101] Through the above embodiments, the technical solution of this application can determine the voltage pulse signal corresponding to the transient current signal through the transient current signal. The technical solution of this application can determine the single deposition energy corresponding to the pulse amplitude through the pulse amplitude. The technical solution of this application can determine the linear energy value of a single event through the single deposition energy and the average chord length of the sensitive volume. The technical solution of this application can traverse all single events to determine all linear energy values. The technical solution of this application can determine the linear energy frequency distribution data through all linear energy values. The technical solution of this application can determine micro-dosimetric parameters through the linear energy frequency distribution data.

[0102] The technical solution of this application achieves the coupling conversion of transient current signals to microdosimetric parameters by introducing calibration and calculation related to the material properties and structural parameters of SiC microdose detectors, thereby improving the accuracy and repeatability of microdose measurement under high dose rate conditions.

[0103] According to another aspect of this application, this application also provides a non-volatile computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is capable of implementing the microdosimetric parameter acquisition method as described above.

[0104] According to another aspect of this application, this application also provides an electronic device, including: one or more processors; and a storage device for storing one or more programs, which, when executed by one or more processors, enable the one or more processors to implement the microdosimetric parameter acquisition method as described above.

[0105] According to another aspect of this application, this application also provides a computer program product, comprising: a computer program stored on a computer-readable storage medium; the computer program includes program instructions that, when executed by a computer, cause the computer to perform the microdosimetric parameter acquisition method as described above.

[0106] Finally, it should be noted that the above description is merely a preferred embodiment of this application and is not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions of the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A silicon carbide micro-dose detector, characterized in that, include: The back electrode layer is connected to the high-voltage potential of the external bias voltage; An N-type heavily doped silicon carbide layer is disposed on the back electrode layer; An intrinsic sensitive layer is disposed on the N-type heavily doped silicon carbide layer in a first preset structure. The intrinsic sensitive layer is an N-type lightly doped silicon carbide layer, constituting a sensitive element for micro-dose measurement. The first preset structure is a columnar, prismatic, or near-spherical shape. A p-type heavily doped silicon carbide layer is disposed on the intrinsic sensitive layer in a second preset structure, wherein the cross-section of the second preset structure is the same as the cross-section of the first preset structure; A front electrode layer is connected to the reference potential of the external bias voltage, and the front electrode layer is disposed on the P-type heavily doped silicon carbide layer; The N-type heavily doped silicon carbide layer, the intrinsic sensitive layer, and the P-type heavily doped silicon carbide layer form a PIN junction structure, which has a built-in electric field. When radiating particles are incident on the sensitive body, energy is deposited within the sensitive body and electron-hole pairs are generated. Under the action of the built-in electric field and the external bias voltage, the electron-hole pairs are collected and converted into electrical signals, and the front electrode layer outputs a transient current signal.

2. The micro-dose detector according to claim 1, characterized in that, The material of the front electrode layer is one or more of aluminum, nickel, titanium, gold, platinum, their alloys, and multilayer composite structures formed by aluminum, nickel, titanium, gold, and platinum.

3. The micro-dose detector according to claim 1, characterized in that, The doping element of the P-type heavily doped silicon carbide layer is aluminum, boron, gallium, or a combination thereof, and the doping concentration of the doping element in the P-type heavily doped silicon carbide layer ranges from 1 × 10⁻⁶. 18 cm -3 ~5×10 19 cm -3 The thickness of the P-type heavily doped silicon carbide layer ranges from 0.2 μm to 2 μm.

4. The micro-dose detector according to claim 1, characterized in that, The intrinsically sensitive layer is doped with nitrogen, phosphorus, or a combination thereof, and the doping concentration of the intrinsically sensitive layer is in the range of 1 × 10⁻⁶. 13 cm -3 ~5×10 14 cm -3 The thickness of the intrinsic sensitive layer ranges from 2μm to 10μm.

5. The micro-dose detector according to claim 1, characterized in that, The doping element of the N-type heavily doped silicon carbide layer is nitrogen, phosphorus, or a combination thereof, and the doping concentration of the doping element in the N-type heavily doped silicon carbide layer ranges from 1 × 10⁻⁶. 18 cm -3 ~1×10 19 cm -3 The thickness of the N-type heavily doped silicon carbide layer ranges from 200 μm to 500 μm.

6. The micro-dose detector according to claim 1, characterized in that, The material of the back electrode layer is one or more of titanium, nickel, aluminum, gold, molybdenum, their alloys, and multilayer composite structures formed by titanium, nickel, aluminum, gold, and molybdenum.

7. The micro-dose detector according to claim 1, characterized in that, When the first preset structure is a column, the diameter of the cylinder ranges from 2μm to 30μm, and the height of the cylinder ranges from 2μm to 10μm. When the first preset structure is a prism or a near-spherical shape, the equivalent lateral feature size of the prism or near-spherical shape ranges from 2μm to 30μm, and the thickness of the prism or near-spherical shape ranges from 2μm to 10μm.

8. The micro-dose detector according to claim 1, characterized in that, Multiple sensors are arranged in an array, adjacent sensors have a preset size, and the multiple sensors are connected by a bridge interconnection structure.

9. A method for preparing a silicon carbide micro-dose detector, characterized in that, The preparation method is used to prepare the microdose detector as described in any one of claims 1-8, and the preparation method includes: N-type heavily doped silicon carbide layers were prepared from 4H-SiC single crystals. An initial intrinsic sensitive layer is epitaxially grown on the first surface of the N-type heavily doped silicon carbide layer, wherein the initial intrinsic sensitive layer is an N-type lightly doped silicon carbide layer. Acceptor doping elements are implanted in a predetermined region on the first surface of the initial intrinsic sensitive layer to form an initial p-type heavily doped silicon carbide layer. The initial P-type heavily doped silicon carbide layer and the initial intrinsic sensitive layer are etched to obtain an intrinsic sensitive layer with a first preset structure and a P-type heavily doped silicon carbide layer with a second preset structure, wherein the first preset structure is a columnar, prismatic, or near-spherical shape, and the cross-section of the second preset structure is the same as the cross-section of the first preset structure. A back electrode layer is formed on the second surface of the N-type heavily doped silicon carbide layer; A front electrode layer is formed on the first surface of the p-type heavily doped silicon carbide layer to form the microdose detector.

10. A method for obtaining microdosimetric parameters, characterized in that, include: Receive the transient current signal output from the micro-dose detector as described in any one of claims 1-8 corresponding to a single event; Based on the transient current signal, determine the voltage pulse signal corresponding to the transient current signal; Based on the voltage pulse signal, determine the pulse amplitude corresponding to the single event; Based on the pulse amplitude, determine the single deposition energy corresponding to the pulse amplitude; The linear energy value of the single event is determined based on the single deposition energy and the average chord length of the sensitive volume; Iterate through all single events to determine all line energy values; Based on all the aforementioned line energy values, determine the line energy frequency distribution data; Based on the linear energy frequency distribution data, microdosimetric parameters are determined.

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