Design and preparation method of modified diamond with multi-signal sensing function

Abstract

The present invention discloses a design and preparation method of a modified diamond with a multi-signal sensing function, and relates to the technical field of new sensor manufacturing. The method includes: dividing the surface of the diamond to be doped into a plurality of regions to be doped according to the sensing area required for the diamond to sense different types of environmental signals; designing geometric parameters corresponding to different types of environmental signals for the plurality of regions to be doped according to the characteristics of different types of environmental signals, so as to change the physical distance between different doped regions and the interaction between adjacent regions; doping the plurality of regions to be doped with corresponding elements according to the geometric parameters and a gradient doping model that makes the electric field transition of the boundary of the region to be doped smooth, so as to obtain a modified diamond with a multi-signal sensing function. Through the above scheme, the present invention can sense multiple signals at the same time, reduce the electric field coupling effect between different doped regions, and improve the accuracy of sensing different signals.

Description

Technical Field

[0001] The present invention relates to the technical field of novel sensor manufacturing, and in particular to a design and preparation method of a modified diamond with a multi-signal sensing function. Background Art

[0002] Diamond is widely used in various industrial, electronic and optical devices due to its excellent mechanical strength, thermal conductivity, corrosion resistance and optical transparency. However, although traditional diamond materials have excellent physical and chemical properties, their application in the fields of electronics and sensing is limited. This is mainly because diamond is a wide-bandgap semiconductor with extremely low electrical conductivity and lacks sensing function, making it difficult to meet application scenarios with higher requirements for electronic response and sensing performance.

[0003] With the aging of the global population and the rising incidence of chronic diseases (such as diabetes and cardiovascular disease), the market demand for implantable sensors has risen sharply. The demand for implantable sensors in the biomedical field is growing rapidly, especially in long-term disease management (such as diabetes monitoring, cardiac function monitoring) and biomonitoring. Although the commonly used implantable sensor materials (such as polymers or metals) on the market have certain biocompatibility, they generally have problems such as decreased sensitivity, material aging, and signal attenuation. In addition, frequent equipment replacement increases medical costs and patient burden, which puts higher requirements on implantable sensors. At the same time, single signal sensors also have limitations in implantable devices. For example, heart monitoring devices can only sense heart rate. If blood oxygen or electrolyte concentration needs to be detected at the same time, patients must use multiple devices, which increases the burden of surgery and replacement. Diamond itself has extremely high biocompatibility, which means that the material is not easy to cause rejection after being implanted in the human body. Through the partitioned doping of multiple elements such as boron and sulfur, the diamond material has the ability to perceive environmental changes, especially to detect external conditions (such as temperature, pressure, concentration, etc.) through changes in resistance. Diamond as an implantable sensor also has the advantages of long-term stability and corrosion resistance.

[0004] At the same time, diamond materials can maintain stability under high temperature, high pressure and corrosive environments, while traditional sensor materials may degrade or fail under these conditions. The sensing function of diamond after doping gives it the ability to respond sensitively to small environmental changes (such as pressure and chemical composition), which is particularly suitable for environmental monitoring in industries such as oil, natural gas, and chemicals. In addition, due to its high hardness and high temperature resistance, diamond can work stably for a long time in harsh aerospace environments. Doped and modified diamond can not only withstand high temperature and high pressure, but also detect important parameters such as mechanical stress and temperature changes, providing accurate data support. Current industrial sensors can usually only sense a single physical parameter, such as temperature, pressure or gas concentration. In order to fully monitor complex industrial environments, multiple types of sensors are usually required to be used in combination. However, multi-sensor systems are not only complex and costly, but there may be interference between sensors, resulting in inaccurate monitoring results. Current industrial sensors can usually only sense a single physical parameter, such as temperature, pressure or gas concentration.

[0005] Therefore, the limitations of traditional diamond materials need to be overcome urgently to meet the needs of sensing functions in these fields.

[0006] In recent years, doping with multiple elements is considered an effective way to enhance the sensing function of materials. By doping with different elements, diamond materials can have multiple sensing capabilities at the same time, expanding their application range. For example, the doping of boron can effectively reduce the resistance of diamond and make it have a certain conductivity. Boron-doped diamond materials are very sensitive to physical signals such as temperature and pressure, and are suitable for pressure sensors and temperature sensors to monitor human blood pressure and temperature, or for pressure and temperature sensing in industry. Sulfur doping can enhance its sensitivity to specific chemical environments. Nitrogen-doped diamonds are sensitive to changes in oxygen concentration and can detect oxygen levels in body fluids or tissues, which is suitable for monitoring blood oxygen saturation. Lithium-doped diamond materials are very sensitive to changes in ion concentration in liquids. Monitoring of cardiac function usually requires real-time detection of changes in the concentration of electrolytes (such as potassium ions, sodium ions, etc.) in body fluids. Lithium doping can give sensors the ability to detect fluctuations in these electrolyte concentrations and help identify electrolyte imbalances, which is very important for the assessment of the health status of cardiac function.

[0007] Therefore, by doping elements such as boron and sulfur into diamond materials, they can be endowed with excellent multifunctional sensing properties.

[0008] At the same time, in the process of partition doping, different regions are doped with different elements (such as boron, sulfur, phosphorus, nitrogen, etc.), and these regions will generate their own electric fields when working. If these doped regions are close to each other, the electric fields between the regions may be coupled, causing the electric fields to affect each other between different regions. This electric field coupling effect will cause the electric field in a certain area to change, interfering with its normal resistance change, and thus affecting the signal output of the area. Also because of the doping of different elements, each region of the diamond material will exhibit different electrical properties. For example, the boron-doped region may exhibit p-type conductivity, and the phosphorus-doped region may exhibit n-type conductivity. Due to the difference in doping regions, carriers (such as electrons and holes) at the boundaries of the regions may diffuse to adjacent regions. This carrier diffusion or migration effect will cause charge imbalance between regions, resulting in inaccurate measurement signals.

[0009] Therefore, when the prior art dopes diamond with multiple elements, it is impossible to avoid the electric field coupling effect caused by the doping of multiple elements, resulting in interference between different types of environmental signals when sensing multiple types of environmental signals, making it impossible to accurately sense multiple types of environmental signals at the same time. Summary of the invention

[0010] Based on this, it is necessary to provide a design and preparation method for a modified diamond with multi-signal sensing function to address the above technical problems.

[0011] The present invention adopts the following technical solutions:

[0012] In a first aspect, the present invention provides a method for designing and preparing a modified diamond having a multi-signal sensing function, the method comprising:

[0013] According to the sensing area required for diamond to sense different types of environmental signals, the surface of the diamond to be doped is divided into multiple areas to be doped;

[0014] According to the characteristics of the different types of environmental signals, geometric parameters corresponding to the different types of environmental signals are respectively designed for the multiple regions to be doped, so as to change the physical distance between the different doping regions and the interaction between adjacent regions;

[0015] According to the geometric parameters and a gradient doping model that makes the electric field transition smooth at the boundary of the region to be doped, the plurality of regions to be doped are doped with corresponding elements respectively to obtain a modified diamond with a multi-signal sensing function.

[0016] Furthermore, the diamond surface to be doped is divided into a plurality of areas to be doped according to the sensing area required for the diamond to sense different types of environmental signals, specifically including:

[0017] Calculating the minimum sensing area required to meet the detection accuracy of the different types of environmental signals;

[0018] The surface of the diamond to be doped is divided into a plurality of areas to be doped based on the minimum sensing area required for the detection accuracy of the different types of environmental signals.

[0019] Furthermore, according to the characteristics of the different types of environmental signals, the geometric parameters corresponding to the different types of environmental signals are respectively designed for the multiple regions to be doped, specifically including:

[0020] Calculating the interaction force between any adjacent regions to be doped among the regions to be doped according to the characteristics of the elements to be doped in the regions to be doped;

[0021] Calculating a minimum distance between the boundaries of any adjacent regions to be doped, so as to satisfy that the interaction force between any adjacent regions to be doped is less than a first preset threshold;

[0022] Designing the shapes of the plurality of regions to be doped so that the distance between any adjacent regions to be doped is greater than or equal to the minimum distance between the boundaries of any adjacent regions to be doped;

[0023] The minimum distance between the boundaries of any adjacent regions to be doped and the shapes of the multiple regions to be doped are integrated to obtain geometric parameters of the multiple regions to be doped.

[0024] Furthermore, after designing the shapes of the plurality of regions to be doped so as to satisfy that the distance between any adjacent regions to be doped is greater than or equal to the minimum distance between the boundaries of any adjacent regions to be doped, the method further comprises:

[0025] When the shape of the region to be doped is designed to be square, the four corners of the region to be doped are designed to be rounded;

[0026] When the shape of the region to be doped is designed to be circular, the edge of the region to be doped is designed to be a smooth edge.

[0027] Furthermore, the step of doping the plurality of regions to be doped with corresponding elements respectively according to the geometric parameters and the gradient doping model that makes the electric field transition at the boundary of the region to be doped smooth includes:

[0028] Using the geometric parameters, calculating the coordinates corresponding to the central area, the middle area and the edge area of ​​each area to be doped;

[0029] At the coordinates corresponding to the central region, the middle region and the edge region, the corresponding elements are doped with a first doping concentration, a second doping concentration and a third doping concentration, respectively, to obtain doped regions associated with the respective regions to be doped.

[0030] Furthermore, the coordinates corresponding to the central region, the middle region and the edge region are doped with the corresponding elements at the first doping concentration, the second doping concentration and the third doping concentration respectively, including:

[0031] In the central region, implanting at a surface depth of the region to be doped using a first energy value and a first ion concentration, wherein the first ion concentration is obtained based on the first doping concentration;

[0032] In the middle region, implanting at a middle layer depth of the to-be-doped region using a second energy value and a second ion concentration, wherein the second ion concentration is obtained based on the second doping concentration;

[0033] In the edge region, implantation is performed at a deep depth of the region to be doped using a third energy value and a third ion concentration, wherein the third ion concentration is obtained based on the third doping concentration.

[0034] Further, after obtaining the doped regions associated with the respective regions to be doped, the method further includes:

[0035] Calculating the coupling strength of the electric field between edge regions of any adjacent doped regions;

[0036] When the coupling strength is greater than a second preset threshold, the doping concentration of the element corresponding to the doped region is reduced.

[0037] Furthermore, the method further comprises:

[0038] When element doping is performed on one of the regions to be doped, a mask is used to cover the other regions to be doped.

[0039] Furthermore, the method further comprises:

[0040] After the doped region is obtained, a multi-step annealing process is used to repair the doped region.

[0041] The at least one technical solution adopted in the present invention can achieve the following beneficial effects: the present invention first divides the surface of the diamond to be doped into a plurality of regions to be doped according to the sensing areas required for sensing different types of environmental signals; then, for the plurality of regions to be doped, geometric parameters corresponding to the different types of environmental signals are designed according to the characteristics of the different types of environmental signals; finally, based on the geometric parameters corresponding to the different types of environmental signals, the plurality of regions to be doped are doped with corresponding elements in a gradient doping manner to obtain the modified diamond with multi-signal sensing function.

[0042] The present invention realizes the sensing area required for sensing according to different types of signals, divides the surface of the diamond to be doped into multiple regions to be doped, and dopes the corresponding elements to the multiple regions to be doped respectively by gradient doping, thereby solving the problem that due to the difference in doping regions, the carriers (such as electrons and holes) at the boundaries of the regions may diffuse to the adjacent regions, resulting in the diffusion or migration effect of the carriers causing the charge imbalance between the regions, thereby causing the inaccurate measurement signal. The invention realizes the sensing of multiple signals at the same time, reduces the electric field coupling effect between different doping regions, and improves the accuracy of sensing different signals at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0044] Figure 1 A schematic diagram of a process flow of a modified diamond design and preparation method with multi-signal sensing function provided by the present invention;

[0045] Figure 2 A schematic diagram of element doping of multiple regions to be doped provided by the present invention;

[0046] Figure 3 A physical diagram of a printed circuit board for sensing multiple signals provided by the present invention;

[0047] Figure 4 A schematic diagram of a circuit module for sensing multiple signals provided by the present invention;

[0048] Figure 5 A flowchart of an ion implantation with a multi-signal sensing function provided by the present invention;

[0049] Figure 6 A first principle simulation calculation result diagram of a method for realizing a multi-signal sensing function provided by the present invention;

[0050] Figure 7 This is a diagram of calculation results of ion implantation simulation that implements a multi-signal sensing function provided by the present invention. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0052] The server mentioned in the present invention can be a server set on a business platform, or a device such as a desktop computer, a laptop computer, etc. that can execute the solution of the present invention. For the convenience of description, the following description is only based on the server as the execution subject. The following is a detailed description of the technical solutions provided by various embodiments of the present invention in conjunction with the accompanying drawings.

[0053] Figure 1 The present invention is a schematic flow chart of a method for designing and preparing a modified diamond with a multi-signal sensing function, which specifically includes the following steps:

[0054] S10: Dividing the surface of the diamond to be doped into a plurality of areas to be doped according to the sensing area required for the diamond to sense different types of environmental signals.

[0055] In this embodiment, the different types of environmental signals include but are not limited to: temperature, pressure, and bioelectric signals. The area to be doped refers to an area that has not been doped with elements. The sensing area required for different types of environmental signals is different. For example, sensing pressure or gas concentration requires a larger sensing area, while sensing temperature or bioelectric signals only requires a smaller sensing area.

[0056] Indicative, Figure 2 A schematic diagram of element doping of multiple regions to be doped provided by the present invention.

[0057] refer to Figure 2 By doping different elements, such as boron, sulfur, phosphorus, nitrogen, etc., in different areas of the diamond material to be doped, the modified diamond is obtained to sense different environmental signals (such as temperature, pressure, bioelectric signals, etc.) and realize simultaneous multi-signal sensing.

[0058] The principle of the modified diamond sensing signal is as follows: the modified diamond can respond to environmental changes with resistance, which is manifested as changes in material resistance under different external conditions (such as temperature, pressure, and gas concentration). Based on this resistance change, under the support of a constant current source, the change in resistance leads to a linear or nonlinear change in voltage, and the fluctuation of the voltage signal is used to reflect changes in the external environment. By detecting voltage changes, environmental signals can be effectively converted into voltage signals, thereby achieving accurate perception of environmental parameters.

[0059] The sensing mechanism is based on Ohm's law , that is, under constant current, any change in resistance will cause a corresponding change in voltage. By monitoring the voltage change amplitude and trend in real time, it is possible to sensitively and accurately capture environmental change signals. This design is not only highly sensitive, but also able to maintain stable operation in extreme environments (such as high temperature, strong corrosion, etc.), showing excellent environmental adaptability and reliability.

[0060] Indicative, Figure 3 A physical diagram of a printed circuit board for sensing multiple signals provided by the present invention, Figure 4 A schematic diagram of a circuit module for sensing multiple signals provided by the present invention.

[0061] refer to Figure 4 , the circuit includes: a modified diamond sensor, a constant current source, an amplifier circuit, a filter circuit, an analog-to-digital converter, and a microcontroller. In the circuit, the external signal is processed and transmitted through the circuit module, and the modified diamond sensor provides a stable current through the constant current source to output the resistance change corresponding to the environmental signal, which is then processed by the amplifier circuit and the filter circuit, converted into a digital signal by the analog-to-digital converter, and finally processed and transmitted by the microcontroller. The circuit is specifically composed of: powered by a lithium battery with a capacity of 200mAh. The circuit module uses a constant current chip to provide a constant current of 1mA. The system uses an AD converter based on ADS1115 to convert the collected analog voltage signal into a digital signal. After the digital signal is amplified, it is converted by an analog-to-digital converter (ADC). Finally, the Bluetooth module based on the STM32 processor is responsible for transmitting the processed digital signal to the personal computer (PC) for further analysis and processing. The design ensures high sensitivity, low noise and stability of the signal, and realizes remote data transmission through wired or wireless means, which is suitable for various environmental sensing applications. Among them, the doped area of ​​the modified diamond is connected to the signal processing and transmission circuit through platinum (Pt) electrodes, and the four-probe measurement method is used to reduce the measurement error caused by wire resistance and contact resistance.

[0062] S20: According to the characteristics of the different types of environmental signals, geometric parameters corresponding to the different types of environmental signals are respectively designed for the multiple regions to be doped, so as to change the physical distance between different doping regions and the interaction between adjacent regions.

[0063] In this embodiment, the characteristics of the different types of environmental signals include but are not limited to: the frequency of the signal, the amplitude of the signal, and the waveform of the signal, and the geometric parameters include but are not limited to: the shape of the area to be doped, and the boundary distance between each of the areas to be doped. For example, using a square sensing area to sense pressure has a better sensing effect, and using a circular sensing area to sense gas concentration has a better sensing effect. When dividing the area to be doped, it is necessary to divide the boundary distance between the doping area for measuring pressure and the doping area for measuring temperature as far as possible, because when measuring pressure, it is necessary to directly contact the surface of the object to be measured, which will affect the measurement of temperature at the same time. The propagation medium for temperature and gas concentration is air, so the boundary distance between the doping area for measuring temperature and the doping area for measuring gas concentration can be divided closer.

[0064] S30: doping the plurality of regions to be doped with corresponding elements respectively according to the geometric parameters and a gradient doping model that makes the electric field transition at the boundaries of the regions to be doped smooth, to obtain a modified diamond with a multi-signal sensing function.

[0065] In this embodiment, the gradient doping formula is shown in formula (1):

[0066] (1)

[0067] in, yes The doping concentration at the position, is the initial doping concentration at the center of the doped region, is the parameter that controls the doping concentration decay rate, is the distance from the center of the region to the border.

[0068] Exemplarily, assuming initial conditions (central doping concentration: 10 19 cm -3 , doping area: 20μm 20μm, doping concentration attenuation parameters: 0.5 μm), where The selection needs to take into account both the regional center sensitivity and the boundary signal independence. Then the doping concentration at different positions is calculated according to formula (1) as follows:

[0069] Central Location x =0: 10 19 cm -3 (The highest doping concentration is applied at the center to ensure high sensitivity to the signal); 2 μm from the center: cm -3 ; 5μm from the center: cm -3 ; 8μm from the center: cm -3 ; 10μm from the center: cm -3 .

[0070] According to the calculation results, the gradient formula shown in formula (1) can make the doping concentration decrease nonlinearly from the center to the boundary of the doped area. This attenuation model can avoid the sharp change of doping concentration, thereby reducing the electric field coupling effect between various doping areas.

[0071] based on Figure 1 The design and preparation method of a modified diamond with a multi-signal sensing function shown in the figure first divides the surface of the diamond to be doped into multiple regions to be doped according to the sensing area required for sensing different types of environmental signals. Then the geometric parameters of the multiple regions to be doped are determined. Based on the geometric parameters, the multiple regions to be doped are doped with corresponding elements by gradient doping to obtain the modified diamond with a multi-signal sensing function, thereby realizing the sensing of multiple signals at the same time, reducing the electric field coupling effect between different doping regions, and improving the accuracy of sensing different signals.

[0072] When applying the modified diamond design and preparation method with multi-signal sensing function provided by the present invention, it is not necessary to Figure 1 The steps are executed in the order shown. The specific execution order of the steps can be determined according to needs, and the present invention does not limit this.

[0073] In addition, in one or more embodiments of the present invention, the diamond surface to be doped is divided into a plurality of regions to be doped according to the sensing areas required for sensing different types of environmental signals, specifically including:

[0074] S101: Calculating the minimum sensing areas required to meet the detection accuracy of the different types of environmental signals.

[0075] In this embodiment, the detection accuracy can be changed according to the standards required by different application scenarios. For example, when the detection accuracy requirement for a certain type of signal is relatively high, the area of ​​the to-be-doped region corresponding to the signal can be appropriately increased. For example, if it is mainly used to detect temperature signals, the size of the to-be-doped region can be designed to be 5 μm. 5μm or less to ensure adequate temperature response. For pressure detection or chemical gas monitoring, the size of the area to be doped can be designed to be 10μm 10μm or larger to provide adequate sensitivity and signal coverage.

[0076] S102: Dividing the surface of the diamond to be doped into a plurality of areas to be doped based on the minimum sensing area required to meet the detection accuracy of the different types of environmental signals.

[0077] In this embodiment, Table 1 provides the minimum sensing areas corresponding to different types of environmental signals that meet the detection accuracy.

[0078] Table 1

[0079]

[0080] In this embodiment, referring to Table 1, different sensing areas are required for detecting different types of environmental signals.

[0081] Among them, the functions of each region after doping with corresponding elements are as follows:

[0082] Region A: Boron doping is used for P-type conductivity and pressure detection.

[0083] Region B: Lithium doping is used for p-type conductivity and detection of concentration change signals of electrolytes (such as potassium ions, sodium ions, etc.) in body fluids.

[0084] Region C: Sulfur doping is used for n-type conductivity and is used for chemical gas monitoring such as CO.

[0085] Region D: Nitrogen doping is used for n-type conductivity, which is used for oxygen concentration or biochemical reaction detection.

[0086] Exemplarily, doping is performed in region A first. When boron ions are implanted in region A, a mask is used to cover other regions. First, surface doping is performed at low energy, and then the energy is gradually increased to achieve deep doping. Multi-step doping ensures that boron is evenly distributed throughout the region, thereby reducing lattice defects. At the same time, different concentrations of boron are doped according to the gradient doping model to reduce the field effect. Subsequently, element doping is performed in regions B, C, and D in turn according to the same steps to ensure the best doping effect in each region.

[0087] After the partitioned ion implantation, a multi-step annealing process can be used to address the complexity of multi-element partitioned doping. The annealing environment can be in an inert gas (such as argon) or a high vacuum environment to avoid the effects of oxidation or chemical reactions on the doping effect. First, anneal at a lower temperature (such as 800°C) to repair some lattice defects; then perform a second anneal at a higher temperature (such as above 1000°C) to further activate the doping elements and optimize the electrical properties.

[0088] Finally, after the ion implantation and annealing treatments are completed, by selecting appropriate insulating materials (such as silicon dioxide, silicon nitride, aluminum oxide or polyimide) and coating techniques (such as CVD, sputtering, spin coating or ALD), a high-quality insulating layer can be formed to effectively prevent charge leakage and provide protection for the long-term use of diamond sensors.

[0089] Finally, a platinum electrode or silversmith electrode is prepared in the modified diamond doping area and an insulating layer is prepared to prevent charge leakage. The modified diamond is connected to the signal processing and transmission circuit through a platinum electrode or a silver paste electrode, and a four-probe connection method is used to eliminate the measurement error caused by wire resistance and contact resistance.

[0090] The scheme shown in this embodiment can minimize the areas of different regions to be doped by confirming the minimum sensing area that satisfies the detection accuracy for each type of signal, thereby increasing the distance between different regions to be doped, reducing the electric field coupling between different doping regions, and improving the accuracy of sensing multiple different types of environmental signals.

[0091] In addition, in one or more embodiments of the present invention, the designing of geometric parameters corresponding to the different types of environmental signals according to the characteristics of the different types of environmental signals specifically includes:

[0092] S201: Calculating the interaction force between any adjacent regions to be doped among the regions to be doped according to the characteristics of the elements to be doped in the regions to be doped.

[0093] In this embodiment, the interaction force between any adjacent regions to be doped is calculated according to the characteristics of the elements to be doped in the multiple regions to be doped. The interaction force refers to the electric field force formed by the electric field formed in the region to be doped after the element is doped on another region after the element is doped, which can be calculated according to the number of doping elements and the distance between the regions to be doped.

[0094] The local electric field With charge distribution The relationship between is used to describe the electric field effect of the doped region, as shown in formula (2):

[0095] (2)

[0096] in: Indicates the position of the diamond doped region The electric field strength at . Indicates location The charge density distribution at the electrode is determined by the doping concentration and external effects such as external stress and thermal effect. It is the dielectric constant of the material. The dielectric constant of diamond is usually higher, so it can have a certain inhibitory effect on the electric field effect. is the integral variable, representing the spatial variation of the charge distribution.

[0097] Charge density By doping concentration Decide and be under pressure and temperature gradient The influence of external factors is shown in formula (3):

[0098] (3)

[0099] in: is the charge constant (e.g., the charge of an electron), It is a distribution function of the doping concentration and may show a gradient change depending on the design of the doping area. It is the additional charge effect caused by stress and temperature, which can be qualitatively expressed as a functional relationship based on the measured data.

[0100] Formula (3) qualitatively explains the generation and extension of the field effect. Local doping or gradient doping affects the charge density distribution. , thereby changing the electric field in the doped region By properly designing the doping concentration and consider external stress and temperature The influence of external forces such as can regulate the field effect so that its coupling effect in a specific area is suppressed or offset.

[0101] S202: Calculate the minimum distance between the boundaries of any adjacent regions to be doped, so as to satisfy that the interaction force between any adjacent regions to be doped is less than a first preset threshold.

[0102] In this embodiment, the distance between the boundaries of any adjacent regions to be doped refers to the straight-line distance between the boundaries of adjacent regions to be doped. For conventional electric field coupling, the physical spacing between adjacent regions to be doped is maintained at least above 10 μm. This spacing can significantly reduce electric field overlap and can effectively shield the carrier diffusion effect. In scenarios with high sensitivity requirements, the physical spacing between adjacent regions to be doped can be further increased to 15 μm to 20 μm to completely eliminate the interaction between adjacent regions to be doped.

[0103] S203: Designing shapes of the plurality of regions to be doped so as to satisfy the requirement that a distance between any adjacent regions to be doped is greater than or equal to a minimum distance between boundaries of any adjacent regions to be doped.

[0104] In this embodiment, simple geometric shapes such as square or circle can effectively and evenly distribute the electric field of the doped area, and can avoid the problem of electric field concentration caused by complex geometric shapes. Since the area to be doped is the same area, the square area can have a shorter border distance than the circular area (for example, when the radius is 16, the side length of the square is 4, and the diameter of the circle is 4.514, then the distance from the geometric center of the square to one side of the square is 2, and the distance from the center of the circle to the border of the circle is 2.257, then when the distance between the geometric centers of the two doped areas is equal, the border distance of the square area is greater than the border distance of the circular area). When the distance between the borders of any adjacent areas to be doped is small, the shape of the area to be doped can be determined as a square. When the distance between the borders of any adjacent areas to be doped is large, the shape of the area to be doped can be determined as a circle.

[0105] S204: Integrate the minimum distance between the boundaries of any adjacent regions to be doped and the shapes of the multiple regions to be doped to obtain geometric parameters of the multiple regions to be doped.

[0106] This embodiment calculates the electric field interaction force between any adjacent regions to be doped, confirms the boundary distance of each region to be doped, and then determines the shape of the multiple regions to be doped based on the boundary distance between any adjacent regions to be doped. Finally, based on the boundary distance between any adjacent regions to be doped and the shape of the multiple regions to be doped, the geometric parameters of the multiple regions to be doped are obtained, which can evenly distribute the electric field, avoid charge accumulation and uneven distribution of carriers, reduce the coupling effect between different regions to be doped, and improve the accuracy of the detection signal.

[0107] In addition, in one or more embodiments of the present invention, after designing the shapes of the plurality of regions to be doped so as to satisfy that the distance between any adjacent regions to be doped is greater than or equal to the minimum distance between the boundaries of any adjacent regions to be doped, the method further includes:

[0108] S2031: When the shape of the region to be doped is designed to be a square, four corners of the region to be doped are designed to be rounded.

[0109] S2032: When the shape of the region to be doped is designed to be circular, designing the edge of the region to be doped to be a smooth edge.

[0110] In this embodiment, by smoothing the electric field at the boundary of the doped region, the electric field interaction force between the various regions to be doped can be reduced, thereby reducing the influence of the electric field effect on the measurement signal.

[0111] In addition, in one or more embodiments of the present invention, the step of doping the plurality of regions to be doped with corresponding elements in a gradient doping manner based on the geometric parameters corresponding to the different types of environmental signals specifically includes:

[0112] S301: using the geometric parameters, calculating the coordinates corresponding to the central region, the middle region and the edge region of each region to be doped.

[0113] In this embodiment, for each region to be doped, a plurality of concentric sub-regions are divided with the center of the region as the starting point. The central region refers to the geometric center of the region to be doped, and the element is doped at the maximum doping concentration to ensure the high sensitivity and high conductivity of the region. The middle region refers to the region between the central region and the edge region, and the doping concentration in this region decays exponentially to reduce the electric field interference between regions. The edge region refers to the boundary region of the region to be doped, and the doping concentration in this region is significantly reduced to reduce the carrier diffusion and the coupling effect between the electric fields of adjacent doping regions.

[0114] S302: doping the corresponding elements at the coordinates corresponding to the central region, the middle region and the edge region with a first doping concentration, a second doping concentration and a third doping concentration, respectively, to obtain doped regions associated with the respective regions to be doped.

[0115] In this embodiment, referring to formula (1), the first doping concentration refers to the initial doping concentration at the center of the to-be-doped region. The second doping concentration refers to a doping concentration that decreases with the gradient of formula (1) as the distance from the center of the region to be doped increases. The third doping concentration refers to the lowest doping concentration corresponding to the boundary of the region to be doped.

[0116] It should be noted that the above-mentioned doping process can be adjusted according to application requirements. It is not only suitable for doping with boron, sulfur, etc., but also can introduce other elements (such as phosphorus, nitrogen, etc.) to further expand functional characteristics.

[0117] This embodiment ensures the requirement of accurate signal sensing by doping with high concentration in the center of the area to be doped. The farther away from the center of the area to be doped, the lower the doping concentration is, which further reduces the electric field coupling effect between adjacent areas.

[0118] In addition, in one or more embodiments of the present invention, the coordinates corresponding to the central region, the middle region and the edge region are doped with the corresponding elements at the first doping concentration, the second doping concentration and the third doping concentration, respectively, including:

[0119] S3021: In the central region, implanting at a surface depth of the region to be doped using a first energy value and a first ion concentration, wherein the first ion concentration is obtained based on the first doping concentration.

[0120] S3022: In the middle region, implanting at a middle layer depth of the region to be doped using a second energy value and a second ion concentration, wherein the second ion concentration is obtained based on the second doping concentration.

[0121] S3023: In the edge region, implantation is performed at a deep depth of the region to be doped using a third energy value and a third ion concentration, wherein the third ion concentration is obtained based on the third doping concentration.

[0122] In this embodiment, the first energy value refers to low energy, which is the energy injected for surface doping, so that shallow doping is formed on the surface of the area to be doped, ensuring that the doping element first covers the surface area, and is generally set to 1keV-10keV (selected according to the material and doping element). The first ion concentration refers to the ion concentration used to form the initial distribution of the doping element on the surface of the area to be doped. Due to the low energy, the doping layer is shallow, which is suitable for modifying the response of diamond to the surface signal. Its concentration can be set to 1 10 13 ions / cm 2 —1 10 15 ions / cm 2, the typical implantation depth is several nanometers to tens of nanometers. The second energy value refers to the medium energy, which is used to dope within the medium depth range of the region to be doped to ensure that the ions can penetrate into the middle region of the region to be doped. Its energy size is generally set to 10keV-50keV. The second ion concentration refers to the ion concentration used to enhance the conductivity of the middle part of the material to ensure that the signal can be transmitted from the surface to the inside, which is suitable for a larger range of signal perception, and its concentration size is generally set to 1 10 14 ions / cm 2 —1 10 16 ions / cm 2 , the typical injection depth is tens of nanometers to about 100 nanometers. The third energy value refers to high energy, which is used to form a doping layer deeper in the material to ensure that the doping uniformity extends to the deeper depth of the material. Its energy size is generally set to: 50keV-150keV. The third ion concentration refers to the injection of doping elements into the deep depth of the material, so that there is a relatively uniform doping concentration distribution throughout the thickness of the material, ensuring that the signal can be transmitted from the surface to the deep depth. Its concentration size is generally set to: 1 10 15 ions / cm 2 —1 10 17 ions / cm 2 , with a typical implantation depth of 100 nanometers to several hundred nanometers.

[0123] Optionally, before ion implantation of the doped diamond, the doped diamond is pretreated to ensure the purity of the sample surface and the stability of the crystal structure, thereby ensuring the effect of ion implantation and the uniformity of doping. Wherein, the pretreatment mainly includes surface polishing and surface cleaning. Surface polishing can ensure that the sample surface is smooth and flat, and reduce surface defects, which can be mechanical polishing or chemical mechanical polishing. Surface cleaning mainly includes: first cleaning with an organic solvent, then cleaning with deionized water, and finally drying. Wherein, the ions refer to the ions corresponding to the doping elements.

[0124] This embodiment solves the problem of damage to the ion lattice during the doping process and reduces the amorphization problem through the above technical solution, and makes the ions evenly distributed in the vertical direction of the region to be doped.

[0125] In addition, in one or more embodiments of the present invention, after obtaining the doped regions associated with the respective regions to be doped, the method further includes:

[0126] S303: Calculate the coupling strength of the electric field between edge regions of any adjacent doped regions.

[0127] In this embodiment, the calculation formula of the coupling strength of the electric field is shown in formula (2).

[0128] S304: When the coupling strength is greater than a second preset threshold, reducing the doping concentration of the element corresponding to the doped region.

[0129] In this embodiment, the preset threshold refers to: the maximum coupling strength corresponding to the signal sensing reaching the specified accuracy.

[0130] Through the above technical solution, this embodiment can calculate the coupling strength between the edges of the doped regions after the doping of the to-be-doped regions is completed, thereby preventing the coupling strength from being too large.

[0131] In addition, in one or more embodiments of the present invention, the method further comprises:

[0132] When element doping is performed on one of the regions to be doped, a mask is used to cover the other regions to be doped.

[0133] In this embodiment, Figure 5 The present invention provides a flowchart for realizing ion implantation with multi-signal sensing function. Figure 5 First, ions are implanted into the different doped regions A, B, C, and D of the diamond using mask covering technology to obtain modified diamond with semiconductor properties.

[0134] Through the above technical solution, this embodiment can improve the doping effect and prevent elements from being mistakenly doped into other areas to be doped during the doping process.

[0135] In addition, in one or more embodiments of the present invention, the method further includes:

[0136] After the doped region is obtained, a multi-step annealing process is used to repair the doped region.

[0137] In this embodiment, reference Figure 5 After obtaining the doped region, that is, after obtaining the modified diamond, a multi-step annealing process is used to activate the doped ions and repair the lattice damage, which can further improve the conductive properties of the modified diamond.

[0138] Optionally, refer to Figure 5After the ion implantation and annealing treatment are completed, by selecting suitable insulating materials (such as silicon dioxide, silicon nitride, aluminum oxide or polyimide) and coating techniques (such as chemical vapor deposition (CVD), sputtering, spin coating or atomic layer deposition (ALD)), a high-quality insulating layer can be formed to effectively prevent charge leakage and provide protection for the long-term use of the modified diamond sensor. Finally, platinum electrodes or silversmith electrodes are prepared in the modified diamond doping area and an insulating layer is prepared to prevent charge leakage.

[0139] In this embodiment, the ion implantation process is simulated by SRIM software to obtain an image of the variation of doping concentration with depth. The implantation dose is also quantitatively analyzed. Figure 6 As shown in FIG. 1 , it is a first principle simulation calculation result diagram of a method for realizing a multi-signal sensing function provided by the present invention. Among them, Figure 6 The left half shows the energy values ​​at different K points (G, F, Q, Z, G). K-point is a concept that describes a specific wave vector (momentum) in the Brillouin Zone, which plays a very important role in crystals. K-points are widely used to describe the band structure of crystals, electronic wave functions, and the symmetry of materials. The band structure describes the distribution of electrons in a material at different energy states, especially how electrons are distributed in the energy region between the valence band and the conduction band. It reflects the available energy states of electrons and the motion properties of electrons. The band structure describes the distribution of electrons in a material at different energy states, especially how electrons are distributed in the energy region between the valence band and the conduction band. It reflects the available energy states of electrons and the motion properties of electrons.

[0140] Figure 6 The right half of the graph shows the density of states of electrons corresponding to different energy values. The density of states (DOS) is a physical quantity that describes the distribution of the number of electronic states at different energy levels in a material. It indicates the number of available electronic states per unit energy interval within a certain energy range. The horizontal axis is energy, and the vertical axis is the density of states at that energy. Through the density of states graph, you can intuitively see the distribution of electronic states of a material in different energy regions.

[0141] From the results of energy state structure and state density, it can be seen that impurity energy levels appear after doping, which reduces the bandgap width and improves conductivity. At the same time, the bottom of the conduction band and the top of the valence band are at the same k point, indicating that the carrier transition mode is direct transition, and the conductivity is further improved.

[0142] At the same time, the first-principle simulation calculations were performed using the CASTEP software package in Materials Studio. The results showed that the modified diamond after doping exhibited excellent semiconductor effects and could effectively realize a variety of sensing functions, such as Figure 7 As shown, it is a diagram of the calculation results of ion implantation simulation provided by the present invention for realizing a multi-signal sensing function.

[0143] The above is a design and preparation method of a modified diamond with multi-signal sensing function provided by one or more embodiments of the present invention.

[0144] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of the present invention.

Claims

1. A design and preparation method of modified diamond with multi-signal sensing function, characterized in that: include: According to the sensing area required for diamond to sense different types of environmental signals, the surface of the diamond to be doped is divided into multiple areas to be doped; According to the characteristics of the different types of environmental signals, geometric parameters corresponding to the different types of environmental signals are respectively designed for the multiple regions to be doped, so as to change the physical distance between the different doping regions and the interaction between adjacent regions; According to the geometric parameters and a gradient doping model that makes the electric field transition at the boundary of the to-be-doped region smooth, the plurality of to-be-doped regions are doped with corresponding elements respectively to obtain a modified diamond with a multi-signal sensing function; Among them, according to the characteristics of the different types of environmental signals, the geometric parameters corresponding to the different types of environmental signals are respectively designed for the multiple regions to be doped, specifically including: according to the characteristics of the elements to be doped in the multiple regions to be doped, calculating the interaction force between any adjacent regions to be doped in the multiple regions to be doped; calculating the minimum distance of the boundaries between any adjacent regions to be doped to satisfy that the interaction force between any adjacent regions to be doped is less than a first preset threshold; designing the shapes of the multiple regions to be doped to satisfy that the distance between any adjacent regions to be doped is greater than or equal to the minimum distance of the boundaries between any adjacent regions to be doped; integrating the minimum distance of the boundaries between any adjacent regions to be doped and the shapes of the multiple regions to be doped to obtain the geometric parameters of the multiple regions to be doped; According to the geometric parameters and a gradient doping model that makes the electric field transition at the boundary of the region to be doped smooth, the multiple regions to be doped are doped with corresponding elements respectively, specifically including: using the geometric parameters to calculate the coordinates corresponding to the central region, the middle region and the edge region of each region to be doped; at the coordinates corresponding to the central region, the middle region and the edge region, doping the corresponding elements with a first doping concentration, a second doping concentration and a third doping concentration, respectively, to obtain doped regions associated with each region to be doped.

2. A method for designing and preparing a modified diamond with multi-signal sensing function as claimed in claim 1, characterized in that: The method of dividing the surface of the diamond to be doped into a plurality of areas to be doped according to the sensing area required for the diamond to sense different types of environmental signals specifically includes: Calculating the minimum sensing area required to meet the detection accuracy of the different types of environmental signals; The surface of the diamond to be doped is divided into a plurality of areas to be doped based on the minimum sensing area required for the detection accuracy of the different types of environmental signals.

3. The method for designing and preparing a modified diamond with multi-signal sensing function as claimed in claim 1, characterized in that: After designing the shapes of the plurality of regions to be doped so as to satisfy that the distance between any adjacent regions to be doped is greater than or equal to the minimum distance between the boundaries of any adjacent regions to be doped, the method further comprises: When the shape of the region to be doped is designed to be square, the four corners of the region to be doped are designed to be rounded; When the shape of the region to be doped is designed to be circular, the edge of the region to be doped is designed to be a smooth edge.

4. The method for designing and preparing a modified diamond with multi-signal sensing function according to claim 1, characterized in that: The coordinates corresponding to the central region, the middle region and the edge region are doped with the corresponding elements at the first doping concentration, the second doping concentration and the third doping concentration respectively, including: In the central region, implanting at a surface depth of the region to be doped using a first energy value and a first ion concentration, wherein the first ion concentration is obtained based on the first doping concentration; In the middle region, implanting at a middle layer depth of the to-be-doped region using a second energy value and a second ion concentration, wherein the second ion concentration is obtained based on the second doping concentration; In the edge region, implantation is performed at a deep depth of the region to be doped using a third energy value and a third ion concentration, wherein the third ion concentration is obtained based on the third doping concentration.

5. The method for designing and preparing a modified diamond with multi-signal sensing function as claimed in claim 1, characterized in that: After obtaining the doped regions associated with the respective regions to be doped, the method further includes: Calculating the coupling strength of the electric field between edge regions of any adjacent doped regions; When the coupling strength is greater than a second preset threshold, the doping concentration of the element corresponding to the doped region is reduced.

6. The method for designing and preparing a modified diamond with multi-signal sensing function according to claim 1, characterized in that: The method further comprises: When element doping is performed on one of the regions to be doped, a mask is used to cover the other regions to be doped.

7. The method for designing and preparing a modified diamond with multi-signal sensing function as claimed in claim 1, characterized in that: The method further comprises: After the doped region is obtained, a multi-step annealing process is used to repair the doped region.

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