High-temperature measurement method based on multi-energy ion implantation doped SiC wafer
By using multi-energy ion implantation to dope SiC wafers and combining it with carbon film protection, the problem of accurate measurement in ultra-high temperature environments in existing high-temperature measurement technologies has been solved, achieving high-temperature measurement above 1700℃. It is suitable for closed systems and moving parts, and has high precision and wide applicability.
Patent Information
- Application Number
- CN202511698071.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-19
- Publication Date
- 2026-02-13
AI Technical Summary
Existing high-temperature measurement technologies are difficult to achieve accurate measurements in ultra-high temperature environments. Contact methods suffer from probe ablation and unstable signal transmission, while non-contact methods are greatly affected by the surface condition of the object. Existing wireless passive temperature measurement methods are difficult to measure effectively above 1500℃.
Multi-energy ion implantation was used to dope SiC wafers to form a uniform impurity doping concentration. The slope of the diffusion concentration curve was extracted by the impurity diffusion behavior to characterize the temperature. Combined with carbon film protection of SiC surface, the impurity concentration-depth curve was analyzed by SIMS for high-temperature measurement.
It enables high-temperature measurements above 1700℃, is suitable for enclosed systems and moving parts, has high measurement accuracy, a wide range of applications, and reduces environmental impact and measurement errors.
Smart Images
Figure CN121521296A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of measurement and testing technology, specifically relating to a high-temperature measurement method based on multi-energy ion implantation doped SiC wafers. Background Technology
[0002] In fields such as energy and power, high-end manufacturing, and national defense, accurate temperature measurement under high-temperature environments is a key technology for system safety, performance optimization, and technological breakthroughs. Especially with the rapid development of my country's aerospace industry, the operating temperatures of hot-end components (turbine blades, combustion chamber walls, nose cones, etc.) of new-generation aero-engines and hypersonic vehicles often far exceed 1700℃, and the measurement environments are often characterized by strong vibrations, high pressures, strong electromagnetic interference, or enclosed conditions, posing severe challenges to temperature measurement technology.
[0003] Existing high-temperature measurement methods mainly fall into two categories: contact and non-contact. Contact methods include thermocouple temperature measurement, crystal thermometry, and temperature-indicating paint temperature measurement; non-contact methods include infrared radiation temperature measurement. Contact methods, such as refractory metal thermocouples, while enabling direct measurement, suffer from problems at ultra-high temperatures, including probe ablation, working fluid contamination, lead wire damage, and poor signal transmission stability. Non-contact methods, such as infrared temperature measurement, do not require contact, but their measurement results are easily affected by the surface condition of the object, medium absorption, and the observation window, making it difficult to directly obtain the true internal or surface temperature of the object.
[0004] Wireless passive temperature measurement methods based on wide-bandgap semiconductor silicon carbide (SiC) have become a research focus in recent years due to the high-temperature stability, radiation resistance, and chemical inertness of SiC itself. The current technology primarily relies on the lattice defects generated after neutron irradiation of SiC. These defects recover to varying degrees at different temperatures, allowing lattice parameters to be determined via X-ray diffraction and compared with standard data to predict temperatures. This method offers advantages such as simple structure and flexible placement, but its temperature measurement mechanism depends on the annealing repair of lattice defects. Defect recovery often saturates around 1500℃, making it difficult to measure temperatures above 1700℃. Subsequently, a SiC wafer temperature measurement method based on ion implantation and impurity diffusion behavior emerged. This method involves ion implantation into SiC, followed by high-temperature measurement of impurity distribution, which is then compared with a calibration curve to infer the temperature experienced by the wafer, achieving high-temperature measurements above 1700℃. This method offers advantages such as ease of operation, the ability to measure higher temperatures, and strong versatility.
[0005] Based on this, the present invention proposes a series of improved methods: covering the SiC crystal surface with a carbon film to protect the SiC surface; using multi-energy ion implantation to form a more uniform impurity doping concentration; and extracting the slope value of the diffusion concentration curve to characterize the temperature. Summary of the Invention
[0006] The purpose of this invention is to provide a high-temperature measurement method based on multi-energy ion implantation doped SiC wafers. Compared to other leadless temperature sensing devices currently in use, this invention can be used for temperature testing above 1700 degrees Celsius, and its application value is significant.
[0007] To achieve the above objectives, the present invention provides a high-temperature measurement method based on multi-energy ion implantation doped SiC wafers, characterized by comprising the following steps: 1) Ions were implanted into the front side of the SiC wafer in multiple batches with different implantation energies and doses, and the maximum ion implantation concentration in the SiC wafer was higher than 10. 19 / cm 3 Furthermore, the injected ions are impurities with diffusion behavior, and the ion doping concentration on the surface of the SiC wafer exhibits a uniform distribution. 2) Photoresist is spin-coated onto the front side of the ion-implanted SiC wafer, and then annealed at a temperature range of 700-900℃. The photoresist undergoes thermal decomposition in the annealing furnace, forming a uniform carbon film covering the front side of the SiC wafer. The above process is carried out in a nitrogen or argon protective environment. 3) Cut the above SiC wafers into several smaller SiC wafer particles according to the temperature measurement task and calibration requirements, and perform visual inspection on these SiC wafer particles, removing wafers with damage, cracks, gaps, etc. 4) Anneal the SiC wafer particles from step 3) in a high-temperature environment with a known temperature. The above process is carried out in a nitrogen or argon protective environment. 5) After high-temperature annealing, the carbon film on the front side of the SiC wafer particles is oxidized in a pure oxygen environment at a temperature that does not damage the SiC wafer to completely remove the carbon film. 6) Secondary ion mass spectrometry (SIMS) analysis was used. The impurity concentration-depth curve of the front surface of the SiC wafer particles was obtained with depth as the horizontal axis and impurity concentration as the vertical axis. The curve was linearly fitted, and the slope k of the fitted line in the tail region of the curve was used as a characteristic parameter to establish a standard reference data table of k as a function of temperature. The curve was then plotted based on the standard reference data table to form a standard reference curve. 7) Use the SiC wafer particles obtained in step 3) for temperature measurement. Anneal the SiC wafer particles in a high-temperature environment with unknown temperature. The above process is carried out in a nitrogen or argon protective environment. 8) Following step 5), oxidize the carbon film on the front side of the SiC wafer particles used for temperature measurement to completely remove the carbon film; 9) Perform SIMS analysis on the front surface of the SiC wafer particle used for temperature measurement to obtain the impurity concentration-depth curve of the SiC wafer particle and extract the characteristic parameter k; compare with the standard reference curve established in step 6) to obtain the temperature corresponding to the characteristic parameter k, which is the temperature to be measured.
[0008] Furthermore, the impurities implanted by the ions can be selected as boron, lithium, hydrogen, nitrogen, phosphorus or aluminum, and the above impurities can have a relatively obvious concentration diffusion at high temperatures.
[0009] Furthermore, the energy range of the implanted ions in step 1) is 1-400 keV. The dose range of the implanted ions is 10. 13 / cm 2 -10 16 / cm 2 The number of injections is 2 to 10 times to achieve a certain depth range below the SiC surface to support diffusion at high temperatures.
[0010] Furthermore, the thickness of the photoresist mentioned in step 2) is in the range of 3-5 micrometers.
[0011] Furthermore, in step 4), the high-temperature annealing time ranges from 10 to 20 minutes.
[0012] Furthermore, the temperature range in step 5) is 800-1100℃.
[0013] This invention utilizes the principle that the diffusion behavior of impurities in SiC wafers at high temperatures is related to the temperature experienced by the wafer. After localized deep doping in the SiC wafer, multiple batches of ion implantation can be used to achieve a uniform distribution of impurities within a small depth range on the front surface layer of the wafer. Figure 1 As shown. Compared with single ion implantation, multi-energy ion implantation can achieve a more uniform doping concentration distribution at different depths. This uniform distribution, as the initial state, helps to form a more regular tail of the concentration-depth curve after subsequent high-temperature diffusion, thereby reducing the extraction error of the slope k value and ultimately improving the testing accuracy.
[0014] At high temperatures, the surface roughness of SiC silicon wafers increases, affecting measurement accuracy. Furthermore, the SiC surface may react with other substances it comes into contact with at high temperatures, affecting the temperature measurement results. Adding a carbon film to the SiC surface can protect the SiC crystal surface, thereby improving measurement accuracy.
[0015] The treated SiC wafer was placed in a high-temperature environment, reaching the same temperature as the wafer itself, causing some diffusion of impurities within the wafer. Afterward, the SiC wafer was removed and the protective layer was removed, and impurity concentration analysis was performed. SIMS analysis yielded a distribution curve of impurity concentration versus depth after high temperature. It was observed that the impurity concentration-depth distribution curve exhibited a regular change. After high-temperature exposure, impurities diffused deeper into the wafer, resulting in a deeper curve at the tail of the concentration curve. This newly added tail curve was formed by diffusion. Furthermore, the slope of the tail curve, i.e., the rate of change of tail concentration with depth, differed significantly at different temperatures. The slope k of the fitted curve is called the characteristic parameter. Experiments showed that the characteristic parameter k increases monotonically with increasing temperature.
[0016] At different temperatures, the analysis described above is performed to extract characteristic parameters k at various temperatures, forming a standard reference curve of k versus temperature. Using this standard reference curve, by comparison and using interpolation or fitting algorithms, the corresponding temperature value can be obtained based on the characteristic parameters k extracted from the SiC wafer after high-temperature treatment, thereby achieving temperature measurement.
[0017] Compared with existing temperature measuring devices, the present invention has the following advantages: 1) This invention provides a temperature measurement method based on multi-energy ion implantation doped SiC wafers. It eliminates the need for any on-site measurement equipment or signal transmission lines, making it suitable for enclosed operating systems, moving parts, etc., and is easy to operate. It enables direct measurement of the actual temperature of the sample being tested, rather than the ambient temperature.
[0018] 2) The present invention has a wide high-temperature measurement range. The present invention is based on the diffusion behavior of impurities at different temperatures, so it is easier to measure higher temperatures. The diffusion behavior characteristics of impurities in SiC can be measured at high temperatures up to 2000℃.
[0019] 3) The SiC wafer surface is protected with a carbon film, which can be used in different temperature measurement environments, reducing the impact of the environment and reducing the surface roughness of the SiC crystal.
[0020] 4) This invention extracts feature parameters based on the curve slope within the depth range of the curve tail, which helps to reduce random measurement errors.
[0021] 5) This invention has a wide range of applications. The doping of SiC wafers, the type of impurities, and changes in ion energy and dosage during multi-energy ion implantation all affect the temperature measurement results, making it suitable for different temperature measurement needs and easy to adjust. It has significant application prospects. Attached Figure Description
[0022] Figure 1 This is a schematic diagram of the structure of the multi-energy ion implantation doped SiC wafer of the present invention. Wherein: 1—the protective carbon film on the surface of the SiC wafer; 2—the impurity doping layer on the surface of the SiC wafer; 3—the undoped region of the SiC wafer; Figure 2 This is a schematic diagram of the impurity concentration-depth curve of the SiC wafer in an embodiment of the present invention. The figure shows a comparison of the concentration curves of two samples, one that has not undergone high temperature and the other that has undergone high temperature. It also illustrates the linear fitting of the tail region of the curve, and the slope k of the fitted curve y=kx+c is used to determine the characteristic parameters. Detailed Implementation
[0023] To make the technical solution of the present invention clearer, it will be described in detail below with reference to the accompanying drawings.
[0024] This invention provides a high-temperature measurement method for multi-energy ion implantation doped SiC wafers, the steps of which are as follows: 1) Prepare a 4-inch intrinsic SiC wafer with a thickness of 300-500 micrometers and clean it thoroughly.
[0025] 2) The impurities for ion implantation are selected as boron, lithium, hydrogen, nitrogen, phosphorus or aluminum. Ions are implanted into the front side of the SiC wafer in multiple batches with different implantation energies and doses. The implanted impurity ions are ions with diffusion behavior. After ion implantation, the ion doping concentration at different depths on the entire SiC wafer surface generally shows a uniform distribution.
[0026] The implanted ion energies were 54 keV, 105 keV, 170 keV, 265 keV, and 400 keV, respectively; the implantation doses were 7 × 10⁻⁶ keV, respectively. 14 / cm 2 6×10 14 / cm 2 8×10 14 / cm 2 1×10 15 / cm 2 1.2×10 15 / cm 2 The injection was performed 5 times.
[0027] 3) A 3-micron thick layer of photoresist is spin-coated on the front side of the wafer using a spin coater, and then carbonization is performed at a temperature range of 700-900℃. The photoresist undergoes thermal decomposition in an annealing furnace, forming a uniform carbon film covering the front side of the SiC wafer. The above process is carried out in a nitrogen or argon protective environment. 4) Cut the above-mentioned SiC wafers into several smaller SiC wafer particles according to the temperature measurement task and calibration requirements, and screen these SiC wafer particles to remove wafers with obvious defects. The qualified products become temperature measuring elements, and the samples are numbered for identification and management.
[0028] 5) Some SiC wafer particles were subjected to high-temperature annealing in a known high-temperature environment for 15 minutes. The above process was carried out in a nitrogen or argon protective environment. The temperature was recorded after the high-temperature process was completed.
[0029] 6) Oxidize the carbon film on the front side of the SiC wafer particles in a pure oxygen environment at a temperature (800-1100℃) that does not damage the SiC wafer, and completely remove the carbon film. 7) SIMS analysis was performed on the front surface of SiC wafers that had not undergone high-temperature treatment and those that had undergone high-temperature treatment. Concentration-depth curves of ionic impurities in the wafers were obtained. (See attached reference.) Figure 2 By comparison, the impurity diffusion curve at the tail of the concentration curve was initially determined. A linear fit was performed on the tail region of the curve to obtain the corresponding fitting function y=kx+c. The slope k obtained from the fit was used as a characteristic parameter, and a standard reference data table of the characteristic parameter k changing with temperature was established. Based on this data, a curve was plotted to form a standard reference curve. This invention establishes a significant regularity between the characteristic parameter k and temperature T, which can be described as the characteristic parameter k monotonically increasing with increasing temperature. A negative value of parameter k indicates that the concentration decreases with depth. At lower temperatures, the diffusion at the tail of the concentration curve is insufficient, resulting in a steeper tail and a larger absolute value of the slope; while at higher temperatures, the diffusion at the tail of the concentration curve is more sufficient, extending the curve into a deeper region, forming a flatter curve with a smaller absolute value of the slope. Therefore, a correspondence can be established between the slope at the tail of the concentration curve and the monotonically increasing temperature experienced.
[0030] 8) The SiC wafer particles obtained in step 4) are used for temperature measurement. The SiC wafer particles are annealed in a high-temperature environment with unknown temperature. The high-temperature process is carried out for 15 minutes in a nitrogen or argon protective environment. 9) Oxidize the carbon film on the front side of the SiC wafer particles according to step 6) to completely remove the carbon film; 10) Perform SIMS analysis on the front surface of the SiC wafer particles used for temperature measurement to obtain the impurity concentration-depth curve of the SiC wafer particles and extract the characteristic parameter k. Then, compare it with the pre-established standard reference curve and use interpolation or fitting methods to extract the temperature corresponding to the characteristic parameter k, which is the temperature to be measured, thus completing the temperature measurement.
[0031] The present invention has been described above through detailed implementation examples. Researchers and those skilled in the art can make non-substantial changes in form or content based on the above steps without departing from the scope of protection of the present invention. Therefore, the present invention is not limited to the content disclosed in the above embodiments, and the scope of protection of the present invention should be determined by the claims.
Claims
1. A method for high temperature measurement of a SiC wafer doped by multi-energy ion implantation, characterized in that, The method comprises the following steps: 1) ions are implanted in the front surface of a SiC wafer in multiple batches with different implant energies and doses, the maximum concentration of ion implantation in the SiC wafer is higher than 10 19 / cm 3 , and the implanted ions are impurities with diffusion behavior, and the ion doping concentration of the surface of the SiC wafer presents a uniform distribution; 2) After ion implantation, a photoresist is spin-coated on the front surface of the SiC wafer, and then annealing is performed at a temperature ranging from 700 to 900 DEG C; the photoresist is thermally decomposed in the annealing furnace to form a uniform carbon film on the front surface of the SiC wafer; the above process is performed in a nitrogen or argon protective environment; 3) The SiC wafer is cut into smaller SiC wafer particles according to the temperature measurement task and calibration requirements, and appearance inspection is performed on the SiC wafer particles; the wafer particles with damage, cracks, notches and the like are removed; 4) The SiC wafer particles in step 3) are annealed in a high-temperature environment with a known temperature; the above process is performed in a nitrogen or argon protective environment; 5) After high-temperature annealing, the carbon film on the front surface of the SiC wafer particle is oxidized in a pure oxygen environment without damaging the SiC wafer, and the carbon film is completely removed; 6) Secondary ion mass spectrometry (SIMS) analysis is performed to obtain an impurity concentration-depth curve of the front surface layer of the SiC wafer particle with depth as the horizontal axis and impurity concentration as the vertical axis; linear fitting is performed on the curve; the slope k of the fitting straight line in the tail region of the curve is taken as a characteristic parameter; a standard reference data table of k with respect to temperature is established, and a standard reference curve is drawn according to the standard reference data table; 7) The SiC wafer particles obtained in step 3) are used for temperature measurement; the SiC wafer particles are annealed in a high-temperature environment with an unknown temperature; the above process is performed in a nitrogen or argon protective environment; 8) The carbon film on the front surface of the SiC wafer particle for temperature measurement is oxidized according to step 5), and the carbon film is completely removed; 9) SIMS analysis is performed on the front surface layer of the SiC wafer particle for temperature measurement to obtain an impurity concentration-depth curve of the SiC wafer particle, and a characteristic parameter k is extracted; The temperature corresponding to the characteristic parameter k is obtained by comparing the standard reference curve established in step 6), and the temperature is the measured temperature.
2. The method for high temperature measurement of a SiC wafer based on multi-energy ion implantation doping as claimed in claim 1, wherein, The impurity in step 1) is boron, lithium, hydrogen, nitrogen, phosphorus or aluminum.
3. The method for high temperature measurement of a SiC wafer doped by multi-energy ion implantation according to claim 1, wherein, The ion energy range for implantation in step 1) is 1-400 keV, the dose range for the implanted ions is 10 13 / cm 2 -10 16 / cm 2 , and the number of implantations is 2-10 times.
4. The method for high temperature measurement of a SiC wafer doped by multi-energy ion implantation according to claim 1, wherein, The thickness of the photoresist ranges from 3 to 5 microns.
5. The method for high temperature measurement of a SiC wafer doped by multiple energy ion implantation as claimed in claim 1, wherein, The high-temperature annealing time in step 4) ranges from 10 to 20 minutes.
6. The method for high temperature measurement of a SiC wafer doped by multiple energy ion implantation as claimed in claim 1, wherein, The temperature in step 5) ranges from 800 to 1100 DEG C.
7. The method for high temperature measurement of a SiC wafer doped by multi-energy ion implantation according to claim 1, wherein, The temperature corresponding to the characteristic parameter k is extracted by interpolation or linear fitting method by comparing the standard reference curve in step 9).