Titanium carbide film integrated gold-filled silicon pore x-ray detector and preparation method

Abstract

This invention discloses a titanium carbide film integrated gold-filled silicon aperture X-ray detector and its fabrication method, comprising: a silicon layer with a bottom contact electrode disposed below it and an insulating dielectric layer with perforated windows disposed above it; a nanopore array disposed on the inner surface of the silicon layer within the region corresponding to the perforated windows and connected to the silicon layer; gold nanopillar structures disposed at the bottom of the nanopores; a top electrode disposed above the insulating dielectric layer, the top electrode not covering the main detection area of ​​the perforated windows, and electrically connected to the detection area corresponding to the perforated windows through the titanium carbide nanofilm covering it; and a titanium carbide nanofilm disposed above the top electrode, the insulating dielectric layer, the gold nanopillar structures, and the nanopore array and in direct contact. This invention utilizes the built-in electric field of the titanium carbide nanofilm / silicon Schottky junction to promote the separation and collection of radiative carriers, achieving low-bias, high-sensitivity, and long-term stable direct X-ray detection.

Description

Technical Field

[0001] This invention belongs to the field of photoelectric detection technology and relates to a titanium carbide film integrated gold-filled silicon hole X-ray detector and its preparation method. Background Technology

[0002] With societal progress and technological advancements, high-energy radiation detection technologies such as X-rays have wide-ranging applications in medical imaging, industrial non-destructive testing, security and surveillance, national defense, radiation dose monitoring, and space exploration. In recent years, direct-type semiconductor X-ray detectors have shown significant potential for low-dose detection, high-resolution imaging, and integrated readout due to their ability to directly convert incident high-energy photons into charge signals, eliminating the intermediate light conversion process. Silicon-based detectors, in particular, possess advantages such as good material uniformity, mature fabrication processes, ease of arraying, and compatibility with integrated circuit technologies, making them an important platform for constructing on-chip integrated X-ray detectors. However, silicon is a low atomic number material with limited X-ray absorption capacity. Especially in thinner and integrated devices, insufficient interaction between incident photons and the effective detection area limits the number of radiative carriers generated, making it difficult to meet the requirements for high-sensitivity, low-dose detection. According to Kramers' classical X-ray emission theory, the X-ray attenuation coefficient μ is proportional to Z. 4 / AE 3 In this context, Z represents the atomic number, A represents the atomic mass, and E represents the X-ray photon energy. Therefore, material composition, device structure, and carrier transport characteristics all affect X-ray detection performance. Thus, combining new materials and structures with silicon-based detection technology is key to achieving highly sensitive, low-power, and integrable X-ray detectors.

[0003] Chinese patent CN109841636B discloses an X-ray detector, a method for manufacturing an X-ray detector photoelectric conversion layer, and a medical device. The patent describes a method that converts X-rays into visible light using a scintillator, and then uses a porous photoelectric conversion layer to read the electrical signal. While this method improves photoelectric conversion efficiency to some extent, it remains an indirect X-ray detector, unable to avoid light scattering, diffusion, and multi-step energy conversion losses from the scintillator. The device structure is complex, and its imaging resolution and miniaturization integration capabilities are significantly limited.

[0004] Chinese patent application CN117954458A discloses the application of enhanced graphene-semiconductor heterojunctions in X-ray detection. This patent mentions a three-layer structure consisting of a high atomic number enhancement layer, a graphene nanofilm, and a semiconductor layer to improve X-ray detection performance. While this approach introduces high atomic number materials to enhance absorption, the overall structure remains primarily planar layered. The coupling depth between the high atomic number materials and the silicon-based active region is limited, making it difficult to form a localized enhanced absorption region within the silicon. Therefore, the improvement in the radiative carrier generation capability within the silicon-based detection region is still insufficient.

[0005] Chinese patent application CN117866619A discloses a perovskite quantum dot material, its preparation method, and its applications. Chinese patent application CN116815326A discloses a bicore-shell perovskite semiconductor single crystal and its preparation method. These perovskite materials typically possess strong X-ray absorption capabilities, but their material systems generally face problems such as poor environmental stability, difficulty in controlling defects, challenges in large-area uniform fabrication, and insufficient compatibility with silicon-based integration processes. Some lead-containing materials also pose potential environmental and packaging risks, limiting their long-term reliable applications.

[0006] This invention represents the first successful macroscopic assembly of a titanium carbide nanofilm combined with a gold-filled silicon nanopore array, addressing the problems of low atomic number, weak X-ray absorption, and insufficient radiative carrier generation in existing silicon-based X-ray photodetectors. By constructing a gold-filled nanopore array within a silicon substrate, localized high atomic number absorption enhancement is achieved within the active region of the silicon substrate. Simultaneously, the built-in electric field of the titanium carbide / silicon Schottky junction efficiently separates and collects radiation-induced electron-hole pairs, significantly improving the X-ray detection sensitivity of the device. This represents a significant breakthrough for low-dose, high-sensitivity direct X-ray detection. Furthermore, this invention can operate at low bias voltages and exhibits good long-term stability and silicon-based process compatibility, promising the realization of low-power, integrable X-ray detection devices. Therefore, the inventors have proposed this invention. Summary of the Invention

[0007] The purpose of this invention is to address the technical problems existing in the prior art by providing a titanium carbide film integrated gold-filled silicon nanopore X-ray detector and its preparation method. This invention is the first to achieve macroscopic assembly of a titanium carbide nanofilm and a gold-filled silicon nanopore array, solving the problems of low atomic number of silicon material, weak X-ray absorption, and insufficient generation of radiative carriers in existing silicon-based X-ray photodetectors.

[0008] To achieve the above functions, the technical features of this invention are as follows:

[0009] A titanium carbide film integrated gold-filled silicon aperture X-ray detector, the detector comprising:

[0010] A silicon layer, with a bottom contact electrode below it and an insulating dielectric layer with perforated windows above it;

[0011] A nanopore array is disposed on the inner surface of the silicon layer within the region corresponding to the perforated window and is connected to the silicon layer; a gold nanopillar structure is disposed at the bottom of the nanopores.

[0012] The top electrode is disposed above the insulating dielectric layer and arranged with the perforated window of the insulating dielectric layer as the center;

[0013] Titanium carbide nanofilms are disposed on top of and in direct contact with the top electrode, the insulating dielectric layer, the gold nanopillar structure, and the nanopore array.

[0014] Furthermore, the titanium carbide nanofilm contacts the silicon layer to form a titanium carbide / silicon Schottky junction, and simultaneously forms an ohmic contact with the top electrode. The bottom contact electrode serves as an ohmic contact between the silicon layer and the external test circuit.

[0015] Furthermore, the gold nanopillar structure and the nanopore array form a gold-filled silicon nanopore array structure. The combination of the gold-filled silicon nanopore array and the macroscopically assembled titanium carbide nanofilm / silicon Schottky junction enables low-dose, high-sensitivity detection of 10 keV, 20 keV and 30 keV X-rays, greatly enhancing the detection response of the planar titanium carbide nanofilm silicon-based X-ray photodetector.

[0016] Furthermore, when X-ray photons are incident on the present invention, the high atomic number of the gold material in the gold-filled silicon nanopore array can significantly enhance the local absorption of X-rays in the silicon-based active region. After absorbing X-rays, the gold-filled layer generates high-energy photoelectrons, which can diffuse into adjacent silicon regions and further induce the generation of electron-hole pairs, thereby increasing the number of radiative charge carriers generated. Meanwhile, the macroscopically assembled titanium carbide nanofilm, as a two-dimensional conductive nanofilm, possesses excellent conductivity, layered carrier transport channels, and abundant surface end groups. After direct contact with the silicon layer, it forms a titanium carbide / silicon Schottky junction and establishes a built-in electric field at the interface. Under the combined action of an applied low bias voltage and the built-in electric field of the Schottky junction, electron-hole pairs induced by X-rays can be rapidly separated. One type of carrier enters the silicon layer and is collected by the bottom contact electrode, while the other type of carrier is transported laterally through the conductive network of the macroscopically assembled titanium carbide nanofilm and transmitted to the top electrode, ultimately forming a readable response current, enabling real-time readout of X-ray signals and intensity. The macroscopically assembled titanium carbide nanofilm not only participates in carrier transport as a conductive collection layer, but also adjusts the barrier height and interfacial electric field distribution at the titanium carbide / silicon interface through its surface end groups and mixed valence states. This helps reduce recombination losses of radiative carriers and improve charge collection efficiency. Simultaneously, shallow-level traps can be formed at the titanium carbide / silicon interface, the gold / silicon interface, and the sidewalls of the silicon nanopores. These shallow-level traps can extend the effective lifetime of carriers under low-dose X-ray irradiation and, in conjunction with a strong built-in electric field, promote carrier detrapping, separation, and transport, thereby generating photoconductivity gain. Therefore, this invention enhances X-ray absorption through a gold-filled silicon nanopore array and enhances carrier separation, transport, and collection through a macroscopically assembled titanium carbide nanofilm / silicon Schottky junction, achieving low-bias, high-sensitivity direct detection of 10 keV, 20 keV, and 30 keV X-rays.

[0017] Further, the fabrication of the gold-filled silicon nanopore array and macroscopically assembled titanium carbide nanofilm composite structure is as follows: Using an anodic aluminum oxide template with a periodic nanopore structure as a hard mask, the silicon layer is etched using ICP (Inductively Coupled Plasma Dry Etching) to first fabricate the patterned nanopore array. Gold material is then deposited onto the nanopore array using physical vapor deposition, electron beam evaporation, thermal evaporation, or magnetron sputtering processes to fill the nanopores, resulting in the gold-filled silicon nanopore array. Subsequently, a macroscopically assembled titanium carbide nanofilm is transferred onto the gold-filled silicon nanopore array and the top electrode, ultimately obtaining the composite structure composed of the gold-filled silicon nanopore array and the macroscopically assembled titanium carbide nanofilm. The structural unit pattern of the nanopore array is designed as a periodic circular nanopore structure. The pore size of the nanopore array is determined by controlling the etching template and etching process according to actual needs, and the pore size range can be 50-300 nm. The depth of the nanopore array is determined by the etching process according to actual needs, and the depth range can be any one between 50-500 nm; the pore spacing of the nanopore array is determined by the anodic aluminum oxide template and nanopatterning process according to actual needs, and the pore spacing range can be any one between 100-800 nm; the thickness of the gold filling layer is determined by the deposition process according to actual needs, and the thickness range can be any one between 10-100 nm; the thickness of the macroscopically assembled titanium carbide nanofilm is determined by the filtration process according to actual needs, and the thickness range can be any one between 30-500 nm.

[0018] Furthermore, the macroscopically assembled titanium carbide nanofilm is a self-supporting nanofilm formed by stacking layers of two-dimensional titanium carbide nanosheets, or it can be a macroscopically assembled titanium carbide nanofilm after surface end-group regulation, metal ion doping, or oxidation treatment. The macroscopically assembled titanium carbide nanofilm can be prepared by solution etching, liquid phase exfoliation, vacuum filtration, or transfer assembly processes, and its thickness can be 30–500 nm.

[0019] Furthermore, the silicon layer and the nanopore array can be made of any one of silicon, germanium, indium gallium arsenide, gallium arsenide, cadmium telluride, indium phosphide, silicon carbide, or gallium nitride. The silicon material described in this invention is just one example. The gold filling layer can be made of any one of high atomic number materials such as gold, platinum, tungsten, bismuth, silver, tantalum, or lead. The gold material described in this invention is just one example.

[0020] Furthermore, the bottom contact electrode can be made of conductive materials such as gallium-indium alloy, nickel silicide, titanium silicide, cobalt silicide, or aluminum electrode to achieve ohmic contact between the silicon layer and the external test circuit. The top electrode can be made of conductive materials such as gold, aluminum, platinum, titanium / gold composite metal, chromium / gold composite metal, or indium tin oxide. The top electrode can be prepared by thermal evaporation, electron beam evaporation, magnetron sputtering, or other thin film deposition processes.

[0021] Furthermore, the window structure in the insulating dielectric layer used to expose the silicon layer can be designed as a circle, rectangle, triangle, quincunx shape, or other regular or irregular polygons according to the device layout requirements. The top electrode is arranged around the window structure, and its arrangement can be a four-sided surround, four-corner symmetrical, herringbone, quincunx, or other electrode layouts that facilitate current collection. The material of the insulating dielectric layer can be silicon dioxide, silicon nitride, silicon oxynitride, boron nitride, aluminum oxide, or titanium dioxide, etc. The insulating dielectric layer can be formed by thermal oxidation, plasma-enhanced chemical vapor deposition, atomic layer deposition, electron beam evaporation, or other thin film deposition processes.

[0022] On the other hand, the present invention also provides a method for fabricating a titanium carbide film integrated gold-filled silicon aperture X-ray detector, the method comprising the following steps:

[0023] (1) Prepare a uniform and ordered anodic aluminum oxide film with periodic nanopores as a hard mask for silicon nanopatterning; specifically: after performing nanoimprint-assisted patterning treatment on the surface of aluminum foil, perform electrochemical anodizing in phosphoric acid solution to form a regular channel structure, and control the increase of pore size and uniformity of pore shape by wet etching to obtain a nanopore array mask with uniformity and long-range order.

[0024] (2) A uniform and ordered anodic aluminum oxide film is aligned and attached to the surface of an N-type silicon substrate covered with a silicon dioxide layer, and a detection window is defined on the silicon dioxide layer by photolithography and buffer oxide etching process; using the uniform and ordered anodic aluminum oxide film as a mask, the silicon layer is etched by ICP to form a vertically arranged silicon nanopore array.

[0025] (3) After the silicon nanopore array is formed, a metal gold layer is deposited in the silicon nanopore array region by physical vapor deposition process to form a metal-filled silicon pore array;

[0026] (4) The macroscopically assembled titanium carbide nanofilm is transferred and covered on the detection window region of the metal-filled silicon hole array, so that the macroscopically assembled titanium carbide nanofilm forms a heterojunction with the silicon substrate and is electrically connected to the electrodes at both ends, thereby completing the fabrication of the X-ray photodetector.

[0027] The beneficial effects of this invention are:

[0028] This invention is the first to achieve macroscopic assembly of a titanium carbide nanofilm combined with a gold-filled silicon nanopore array, solving the problems of low atomic number of silicon materials, weak X-ray absorption, and insufficient radiative carrier generation in existing silicon-based X-ray photodetectors. By enhancing local X-ray absorption in the active region of silicon through the gold-filled silicon nanopore array, and utilizing the built-in electric field of the titanium carbide / silicon Schottky junction to promote carrier separation and collection, a direct X-ray detection with low bias, high sensitivity, and long-term stability is achieved. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of a titanium carbide nanofilm integrated gold-filled silicon nanopore array X-ray photodetector.

[0031] Figure 2 This is a partial cross-sectional view of an X-ray photodetector with a titanium carbide nanofilm integrated gold-filled silicon nanopore array.

[0032] Figure 3 A comparison of the absorption coefficients of gold, titanium carbide, and silicon at different X-ray photon energies;

[0033] Figure 4 This is a flowchart illustrating the fabrication process of a titanium carbide nanofilm integrated gold-filled silicon nanopore array X-ray photodetector.

[0034] Figure 5 A comparison of the X-ray sensitivity of silicon devices, gold-filled silicon nanopore array devices, titanium carbide / silicon devices, and the device of this invention;

[0035] Figure 6 The image shows the photoelectric response test results of this invention under X-ray irradiation at 10 keV, 20 keV, and 30 keV.

[0036] Figure 7 This is a schematic diagram illustrating the X-ray imaging application of the present invention.

[0037] in:

[0038] 1. Titanium carbide nanofilm, 2. Three-dimensional silicon nanopore array, 3. Gold nanopillar structure, 4. Top electrode, 5. Insulating dielectric layer, 6. Silicon layer, 7. Bottom contact electrode. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described below with reference to the accompanying drawings and examples. It should be understood that the specific examples described herein are merely illustrative and not intended to limit the invention.

[0040] like Figure 1 As shown, the insulating dielectric layer 5 is disposed above the silicon layer 6, together forming the main body of the device; the insulating dielectric layer 5 has a perforated window, which exposes the underlying silicon layer 6; the three-dimensional silicon nanopore array 2 is disposed on the inner surface of the silicon layer 6 in the region corresponding to the perforated window, and is connected to the silicon layer 6; the gold nanopillar structure 3 is disposed at the bottom of the nanopores of the three-dimensional silicon nanopore array 2, forming a gold-filled silicon nanopore array structure; the top electrode 4 is disposed above the insulating dielectric layer 5 and located in the outer peripheral region of the detection window; the top electrode 4 is adjacent to the detection window region but does not obstruct the three-dimensional silicon nanopore array 2 and the gold nanopillars. In the main detection area where structure 3 is located, the titanium carbide nanofilm 1 covers the detection window and the top electrode 4, and is in direct contact with the top electrode 4 to enable the top electrode 4 to extract the electrical signal from the titanium carbide nanofilm 1. The macroscopically assembled titanium carbide nanofilm 1 is disposed above and in direct contact with the top electrode 4, the insulating dielectric layer 5, the gold nanopillar structure 3, and the three-dimensional silicon nanopore array 2, and is in contact with the silicon layer 6 to form a titanium carbide / silicon Schottky junction, while also forming an ohmic contact with the top electrode 4. The bottom contact electrode 7 is disposed below the silicon layer 6 and serves as an ohmic contact between the silicon layer 6 and the external test circuit.

[0041] The specific fabrication process of the composite structure of the three-dimensional silicon nanopore array 2, gold nanopillar structure 3, and titanium carbide nanofilm 1 in this invention is as follows: Using an anodic aluminum oxide template with a periodic nanopore structure as a hard mask, the silicon layer 6 is etched using an ICP inductively coupled plasma dry etching system. Sulfur hexafluoride and octafluorocyclobutane can be used as the etching gas. First, the patterned three-dimensional silicon nanopore array 2 is fabricated. Then, gold material is deposited on the three-dimensional silicon nanopore array 2 using physical vapor deposition, electron beam evaporation, thermal evaporation, or magnetron sputtering processes, filling the nanopores of the three-dimensional silicon nanopore array 2 with gold material to obtain the gold nanopillar structure 3. Before transferring the titanium carbide nanofilm 1, the top electrode 4 is prefabricated above the insulating dielectric layer 5 and located in the outer periphery of the detection window. Then, the titanium carbide nanofilm 1 is transferred above the three-dimensional silicon nanopore array 2, the gold nanopillar structure 3, and the top electrode 4, finally obtaining a composite detection structure composed of macroscopically assembled titanium carbide nanofilm 1, three-dimensional silicon nanopore array 2, and gold nanopillar structure 3, as shown below. Figure 1 and Figure 2As shown. The structural unit pattern of the three-dimensional silicon nanopore array 2 is designed as a periodic circular nanopore structure. The pore size, depth, and spacing of the three-dimensional silicon nanopore array 2 can be controlled according to actual needs through anodized aluminum template and etching process; the height or gold filling thickness of the gold nanopillar structure 3 can be controlled by deposition process; the thickness of the titanium carbide nanofilm 1 can be adjusted by filtration process.

[0042] Due to the low atomic number of silicon, its absorption capacity for X-rays is limited, especially in thin silicon-based devices where insufficient interaction between incident X-rays and the effective detection region limits the number of radiative carriers generated. The combination of a three-dimensional silicon nanopore array 2 and a gold nanopillar structure 3 in this invention can, on the one hand, introduce localized high atomic number absorption units within the silicon-based active region, significantly enhancing the X-ray photon trapping capability; on the other hand, the close contact between the gold nanopillar structure 3 and the surrounding silicon layer 6 allows high-energy photoelectrons generated after X-ray absorption by the gold material to diffuse into adjacent silicon regions, further inducing electron-hole pairs, thereby improving the radiative carrier generation efficiency.

[0043] like Figure 3 As shown, the mass decay coefficient of gold materials in the relevant X-ray energy range is significantly higher than that of silicon and titanium carbide, thus effectively compensating for the insufficient absorption of traditional silicon-based X-ray detectors. When X-ray photons are incident on this invention, the gold nanopillar structure 3 first enhances local X-ray absorption and generates high-energy photoelectrons. During the transmission of these high-energy photoelectrons between the gold nanopillar structure 3 and the silicon layer 6, electron-hole pairs are further excited. At the same time, the titanium carbide nanofilm 1, as a two-dimensional conductive nanofilm, has good conductivity, layered carrier transport channels, and abundant surface end groups. After direct contact with the silicon layer 6, it forms a titanium carbide / silicon Schottky junction and establishes a built-in electric field at the interface. Under the combined effect of an applied low bias voltage and the built-in electric field of the Schottky junction, the electron-hole pairs induced by X-rays can be rapidly separated. One type of charge carrier enters the silicon layer 6 and is collected by the bottom contact electrode 7, while the other type of charge carrier is transported laterally through the conductive network of the titanium carbide nanofilm 1 and transmitted to the top electrode 4, ultimately forming a readable response current, enabling real-time readout of the X-ray signal and intensity.

[0044] The titanium carbide nanofilm 1 can also adjust the barrier height and interfacial electric field distribution of the titanium carbide / silicon interface through its surface end groups and mixed valence states, thereby reducing the recombination loss of radiative charge carriers and improving charge collection efficiency. At the same time, shallow energy level traps can be formed at the titanium carbide / silicon interface, the gold / silicon interface, and the sidewalls of the three-dimensional silicon nanopore array 2. These shallow energy level traps can extend the effective lifetime of charge carriers under low-dose X-ray irradiation and, together with a strong built-in electric field, promote the detrapping, separation, and transport of charge carriers, thereby generating photoconductivity gain.

[0045] This invention compares the X-ray detection performance of silicon devices, gold-filled silicon nanopore array devices, and planar titanium carbide / silicon devices, for example. Figure 5 As shown, it can be seen that the present invention achieves higher photocurrent and sensitivity under low bias voltage. Furthermore, Figure 6 The photoelectric response test data of the present invention under X-ray irradiation of 10keV, 20keV and 30keV are shown. It can be found that the present invention exhibits good detection response under different X-ray energy conditions, which greatly enhances the detection performance of the planar titanium carbide nanofilm silicon-based X-ray photodetector. By realizing the first composite of titanium carbide nanofilm 1, three-dimensional silicon nanopore array 2 and gold nanopillar structure 3, the problems of weak X-ray absorption, insufficient radiative carrier generation and limited sensitivity in existing silicon-based X-ray photodetectors are solved.

[0046] To further explore the potential applications of this invention in practical X-ray detection, an exemplary X-ray imaging test was performed on the device of this invention, such as... Figure 7 As shown. Inspired by the high sensitivity and low bias X-ray response of the device of this invention, this invention further demonstrates its application in X-ray imaging. Figure 7 The schematic diagram of the imaging method in the figure shows the testing relationship between the X-ray source, the sample to be tested, the detector of the present invention, and the signal acquisition system. Figure 7 (a) in the figure represents the specific test process. After the X-ray passes through the opaque capsule, it is incident on the device of the present invention. The resulting photocurrent signal is amplified and collected and then reconstructed into an image. Figure 7 (c) in the image represents the imaging result, which can clearly show, for example, Figure 7 The metal spring structure inside the capsule shown in (b) demonstrates that the device of the present invention not only has high X-ray detection sensitivity, but also has the potential for practical X-ray detection and imaging applications.

[0047] In summary, the present invention provides a titanium carbide film integrated gold-filled silicon aperture X-ray detector and its fabrication method, which for the first time achieves the composite of titanium carbide nanofilm 1, three-dimensional silicon nanopore array 2, and gold nanopillar structure 3, solving the problems of low atomic number of silicon material, weak X-ray absorption, and insufficient generation of radiative carriers in existing silicon-based X-ray photodetectors. By enhancing the local X-ray absorption in the active region of silicon through the gold nanopillar structure 3, and utilizing the built-in electric field of the macroscopically assembled titanium carbide nanofilm / silicon Schottky junction to promote the separation, transport, and collection of radiative carriers, low bias voltage, high sensitivity, and long-term stable direct X-ray detection are achieved.

[0048] According to a second aspect of this specification, a method for fabricating a titanium carbide film integrated gold-filled silicon aperture X-ray detector is provided. For example... Figure 4 As shown, the method includes the following steps:

[0049] (1) Preparation of silicon substrate: N-type lightly doped silicon wafers are selected as substrates. The thickness of the silicon wafers is 100-500 μm and the resistivity is 1-10 Ω·cm. After the silicon wafers are cut to the required size, their surfaces are cleaned by ultrasonic cleaning in acetone, isopropanol and deionized water in sequence. After cleaning, the wafers are removed and dried with nitrogen gas for later use.

[0050] (2) Patterning of the top electrode: Photoresist is spin-coated onto the cleaned silicon wafer to form a uniform cover layer, and pre-baked at 105°C for 5 min. Subsequently, the coated silicon wafer is exposed using a photolithography machine. After exposure, a developing solution is prepared by mixing developer and deionized water at a ratio of 1:7 to develop the electrode area. After development, a metal electrode layer can be deposited by processes such as thermal evaporation, electron beam evaporation, or magnetron sputtering. The sample is then placed in acetone for metal stripping to remove excess metal from the non-electrode areas. Finally, the sample is cleaned with isopropanol and dried to obtain the desired top electrode pattern.

[0051] (3) Patterning of the silicon window: After the top electrode preparation is completed, the silicon wafer surface is spin-coated with photoresist, pre-baked, exposed, and developed again to define the silicon window area. After development, the sample is post-baked at 120°C for 20 min to fully cure the photoresist, thereby protecting the oxide layer in the non-window area during subsequent wet etching. Then, the sample is placed in a buffer oxide etching solution to etch the oxide layer in the window area not covered by photoresist. The buffer oxide etching solution can be prepared by ammonium fluoride, hydrofluoric acid, and water in a ratio of 60 g: 30 ml: 100 ml, and its etching rate is about 100 nm / min. When the silicon dioxide layer thickness on the silicon wafer surface is 100 nm, etching for about 1 min is sufficient to expose the silicon window. After etching, the sample is removed and cleaned with deionized water, and then acetone and isopropanol are used sequentially to remove residual photoresist, finally completing the patterning of the silicon window.

[0052] (4) Preparation of anodic aluminum oxide template: High-purity aluminum foil was selected as the substrate and washed sequentially with acetone, isopropanol and deionized water and then dried. Subsequently, a periodic pre-pattern was formed on the surface of the aluminum foil by nanoimprinting, with the pre-pattern period preferably being 400 nm. The patterned aluminum foil was placed in a 0.1-0.5 mol / L phosphoric acid solution for electrochemical anodizing. The anodizing voltage was 120-200 V, the temperature was 0-10℃, and the time was 30-120 min, resulting in an ordered anodic aluminum oxide pore structure. Then, a wet pore-expanding treatment was performed using phosphoric acid solution to increase the pore size and improve the pore shape uniformity, finally obtaining an anodic aluminum oxide template with a periodic nanopore structure, which was used as a hard mask for etching silicon nanopore arrays.

[0053] (5) Fabrication of silicon nanopore array: The anodic aluminum oxide template is aligned and attached to the surface of the silicon substrate with the silicon window patterned, so that it covers the detection window area; then, using the anodic aluminum oxide template as a hard mask, the exposed silicon layer is etched using an ICP inductively coupled plasma dry etching system. The etching gas can be SF6 or C4F8 to form a vertically arranged silicon nanopore array. By controlling the etching time to adjust the nanopore depth, a silicon nanopore array with a pore diameter of about 100 nm, a pore depth of about 100 nm, and a pore spacing of about 400 nm is finally obtained.

[0054] (6) Preparation of gold-filled silicon nanopore array: After the silicon nanopore array is formed, gold material is deposited in the silicon nanopore array region by physical vapor deposition, electron beam evaporation, thermal evaporation or magnetron sputtering process, so that the gold material enters the nanopores of the silicon nanopore array to form a gold-filled silicon nanopore array; the thickness of the gold filling layer is about 50 nm.

[0055] (7) Preparation and transfer of titanium carbide nanofilms: The precursor titanium aluminum carbide powder was added to a mixed solution of lithium fluoride and dilute hydrochloric acid and stirred to etch the aluminum element in the precursor. After centrifugation and washing with deionized water, the solution was finally ultrasonically treated in a cold water bath under an argon atmosphere to obtain a weakly acidic titanium carbide nanosheet dispersion. Preferably, the concentration of the dilute hydrochloric acid was 9 mol / L, and the concentration of the titanium carbide nanosheet dispersion was 5 mg / mL. Subsequently, the titanium carbide nanosheet dispersion was placed in a vacuum filtration flask with an anodic aluminum oxide film as the substrate and vacuum filtered at room temperature for 30-60 min to obtain a self-supporting macroscopically assembled titanium carbide nanofilm. Preferably, the thickness of the macroscopically assembled titanium carbide nanofilm was 30-500 nm. The self-supporting macroscopically assembled titanium carbide nanofilm is directly transferred to the detection window region of the gold-filled silicon nanopore array, simultaneously covering both the detection window and the top electrode. During the transfer, 1-2 drops of deionized water can be added to assist the spreading of the macroscopically assembled titanium carbide nanofilm, and nitrogen gas is used for purging to ensure tight adhesion between the macroscopically assembled titanium carbide nanofilm and the gold-filled silicon nanopore array and the silicon substrate. Simultaneously, it forms an ohmic contact with the top electrode and a titanium carbide / silicon Schottky junction with the silicon layer. The size of the macroscopically assembled titanium carbide nanofilm is sufficient to cover both the detection window and the top electrode region.

[0056] (8) Fabrication of bottom contact electrode: Taking gallium indium alloy as the back contact material as an example, gallium indium alloy is coated on the back of the silicon layer of the device, and copper tape is attached to the coating area or electrical signals are led out by means of gold wire bonding, so that the back of the silicon layer forms a stable ohmic contact with the external test circuit.

[0057] The above embodiments provide an exemplary description of the present invention. Obviously, the specific implementation of the present invention is not limited to the above methods. Any improvements made using the inventive concept and technical solution of the present invention, or direct application to other situations without modification, are all within the protection scope of the present invention.

Claims

1. A titanium carbide film integrated gold-filled silicon aperture X-ray detector, characterized in that, The detector includes: A silicon layer, with a bottom contact electrode below it and an insulating dielectric layer with perforated windows above it; A nanopore array is disposed on the inner surface of the silicon layer within the region corresponding to the perforated window and is connected to the silicon layer; a gold nanopillar structure is disposed at the bottom of the nanopores. The top electrode is disposed above the insulating dielectric layer. The top electrode does not cover the main detection area of ​​the perforated window, and forms an electrical connection with the detection area corresponding to the perforated window through the titanium carbide nanofilm covering it. Titanium carbide nanofilms are disposed on top of and in direct contact with the top electrode, the insulating dielectric layer, the gold nanopillar structure, and the nanopore array.

2. The titanium carbide film integrated gold-filled silicon aperture X-ray detector according to claim 1, characterized in that, The titanium carbide nanofilm forms a titanium carbide / silicon Schottky junction in contact with the silicon layer, and also forms an ohmic contact with the top electrode. The bottom contact electrode serves as an ohmic contact between the silicon layer and the external test circuit.

3. The titanium carbide film integrated gold-filled silicon aperture X-ray detector according to claim 1, characterized in that, The gold-filled silicon nanopore array structure formed by the gold nanopillar structure and the nanopore array, combined with the heterojunction of the titanium carbide nanofilm and silicon, achieves high-performance detection in the X-ray band, enhancing the detection response of the planar macroscopically assembled titanium carbide nanofilm X-ray detector in the corresponding band.

4. The titanium carbide film integrated gold-filled silicon aperture X-ray detector according to claim 1, characterized in that, The X-rays excite the inner-shell electrons of titanium carbide atoms to generate high-density hot electrons. After photon excitation, the hot carriers are in a non-equilibrium state and migrate directionally to the heterojunction of titanium carbide and silicon during the relaxation process of electron-electron scattering and electron-phonon scattering. This increases the probability of hot carriers crossing the Schottky barrier at the interface, forming a photocurrent response under an applied bias voltage. After the incident photon undergoes the photoelectric effect in the metal region, it generates high-energy photoelectrons and secondary electrons. The high-energy photoelectrons are injected into the adjacent silicon mass and induce the generation of more electron-hole pairs, increasing the number of effective carriers and further enhancing the output signal. Based on the synergistic effect of the titanium carbide hot carrier trans-barrier transport effect and the secondary electron injection gain generated by the high absorption of the metal, real-time readout of X-ray signals and intensity is achieved, and the detection sensitivity is improved.

5. The titanium carbide film integrated gold-filled silicon aperture X-ray detector according to claim 3, characterized in that, The structural unit pattern design of the titanium carbide nanofilm and the gold-filled silicon nanopore array is as follows: a periodic circular nanopore array structure is formed in the perforated window area, the nanopores are arranged in a regular pattern with equal spacing, and the array as a whole is a two-dimensional periodic symmetrical distribution. The pore size of the nanopores is determined by controlling the etching template and etching process according to actual needs; The depth of the nanopores is determined by controlling the etching process according to actual needs; the spacing between the nanopores is determined by controlling the anodized aluminum template and nanopatterning process according to actual needs. Gold material is deposited in the nanopores to form a gold-filled layer. The thickness of the gold-filled layer is determined by controlling the deposition process according to actual needs. A titanium carbide nanofilm covers the perforated window area and is aligned and bonded to the gold-filled silicon nanopore array. Its thickness is determined by controlling the filtration process according to actual needs.

6. The titanium carbide film integrated gold-filled silicon aperture X-ray detector according to claim 1, characterized in that, The titanium carbide nanofilm is a multilayer nanofilm macroscopically assembled from layered titanium carbide materials. The surface of the titanium carbide materials has one or more end groups, including those containing oxygen-containing groups, fluorine-containing groups, or hydroxyl-containing groups. Its work function and interfacial electrical properties are adjusted based on doping modification or surface end group regulation. The titanium carbide nanofilm is prepared by vacuum filtration after preparing a titanium carbide nanosheet dispersion by indirect hydrofluoric acid etching.

7. The titanium carbide film integrated gold-filled silicon aperture X-ray detector according to claim 1, characterized in that, The semiconductor substrate material forming the nanopore array is any one of silicon, germanium, gallium arsenide, indium gallium arsenide, indium phosphide, cadmium telluride, silicon carbide, or gallium nitride, and the pore array structure is a nanopore array structure formed on the surface of the above semiconductor material.

8. The titanium carbide film integrated gold-filled silicon aperture X-ray detector according to claim 1, characterized in that, The bottom contact electrode is any one of gallium-indium alloy, metal silicide, or aluminum; the top electrode is any one of gold, aluminum, platinum, titanium-gold alloy, chromium-gold alloy, or indium tin oxide; the deposition process of the top electrode is any one of thermal evaporation, electron beam evaporation, or magnetron sputtering.

9. A titanium carbide film integrated gold-filled silicon aperture X-ray detector according to claim 5, characterized in that, The aperture array has any one of the following aperture shapes: circular, elliptical, or polygonal; the metal material used for the gold filling layer is any one of gold, silver, platinum, tungsten, molybdenum, titanium, chromium, nickel, or aluminum, and the gold filling layer forms a metal filling structure or a metal liner structure; the metal filling layer is prepared by any one of physical vapor deposition, magnetron sputtering, electron beam evaporation, or chemical vapor deposition; the insulating dielectric layer is any one of silicon dioxide, silicon nitride, boron nitride, silicon oxynitride, aluminum oxide, or titanium dioxide; the insulating dielectric layer is prepared by any one of thermal oxidation growth, plasma-enhanced chemical vapor deposition, atomic layer deposition, or electron beam evaporation deposition.

10. A method for fabricating a titanium carbide film integrated gold-filled silicon aperture X-ray detector based on any one of claims 1-9, characterized in that, The preparation method includes the following steps: (1) Prepare a uniform and ordered anodic aluminum oxide film with periodic nanopores as a hard mask for silicon nanopatterning; specifically: after performing nanoimprint-assisted patterning treatment on the surface of aluminum foil, perform electrochemical anodizing in phosphoric acid solution to form a regular channel structure, and control the increase of pore size and uniformity of pore shape by wet etching to obtain a nanopore array mask with uniformity and long-range order. (2) Align the uniform and ordered anodic aluminum oxide film with the silicon layer covered with silicon dioxide, and define the detection window on the silicon dioxide layer by photolithography and buffer oxide etching process; using the uniform and ordered anodic aluminum oxide film as a mask, etch the silicon layer by ICP to form a vertically arranged silicon nanopore array. (3) After the silicon nanopore array is formed, a metal gold layer is deposited in the silicon nanopore array region by physical vapor deposition process to form a metal-filled silicon pore array; (4) The macroscopically assembled titanium carbide nanofilm is transferred and covered on the detection window region of the metal-filled silicon hole array, so that the macroscopically assembled titanium carbide nanofilm forms a heterojunction with the silicon substrate and is electrically connected to the electrodes at both ends, thereby completing the fabrication of the X-ray photodetector.

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