Method for improving performance of silicon carbide semiconductor detector based on electron irradiation

Abstract

The invention discloses a silicon carbide semiconductor detector performance improvement method based on electron irradiation, which belongs to the field of semiconductor devices, and comprises the following steps: selecting a silicon carbide semiconductor detector; silicon carbide semiconductor detectors are grouped; irradiating the sample with electrons; testing the performance of the sample after electron irradiation; determining the optimal cumulative fluence for improving the performance of the silicon carbide semiconductor detector; and performing electron irradiation on the silicon carbide semiconductor detector with the performance to be improved. The performance can be greatly improved without changing the original design of the silicon carbide semiconductor detector by using electron irradiation, the influence on the forward characteristic of the silicon carbide semiconductor detector is small, the dark current, charge collection efficiency and energy resolution of the silicon carbide semiconductor detector can be effectively improved, and the method is not limited by the manufacturing process flow; the method can be implemented before or after the silicon carbide semiconductor detector is packaged, the process is simple, and the application prospect is wide.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor devices, and in particular to a method for improving the performance of a silicon carbide semiconductor detector based on electron irradiation. Background Art

[0002] Compared with traditional silicon-based semiconductor detectors, wide-bandgap silicon carbide semiconductor detectors have stronger radiation resistance, higher critical breakdown field strength, faster carrier saturation drift velocity and better high temperature resistance. Therefore, silicon carbide semiconductor detectors show obvious advantages in nuclear radiation detection application scenarios such as high-flux ray detection, strong pulse ray detection, and charged ion energy spectrum measurement, which is of great significance to the development of nuclear energy and nuclear technology.

[0003] Dark current and energy resolution are important performance indicators of silicon carbide semiconductor detectors, which directly affect the accuracy of nuclear radiation measurement results. However, due to the intrinsic defects in the semiconductor device process, the dark current and energy resolution of silicon carbide semiconductor detectors are still far from specific requirements. Reducing the dark current and energy resolution of silicon carbide semiconductor detectors is of great significance for the further development of nuclear radiation detection technology. However, there is currently no method to improve the performance of silicon carbide semiconductor detectors using electron irradiation. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a method for improving the performance of a silicon carbide semiconductor detector based on electron irradiation, which is easy to implement and can improve dark current and energy resolution.

[0005] The technical solution of the present invention to solve the above technical problems is: a method for improving the performance of a silicon carbide semiconductor detector based on electron irradiation, comprising the following steps: Step S1, selecting a silicon carbide semiconductor detector: Conduct electrical performance tests and alpha particle amplitude spectrum response tests on the silicon carbide semiconductor detectors whose performance needs to be improved, obtain the initial performance indicators of the silicon carbide semiconductor detectors, eliminate the failed silicon carbide semiconductor detectors with abnormal performance indicators, and retain the silicon carbide semiconductor detectors that have not failed; Step S2, grouping silicon carbide semiconductor detectors: Randomly select N non-failed silicon carbide semiconductor detectors as samples and divide them into M groups; Step S3, electron irradiation of the sample: The selected M groups of samples are subjected to electron irradiation with M different cumulative injection doses, and each group of samples adopts the same cumulative injection dose; Step S4, testing sample performance after electron irradiation: Conducting electrical performance test and alpha particle amplitude spectrum response test on the M group of electron-irradiated samples, with the test condition parameters being the same as the test condition parameters in step S1, to obtain the performance indicators of the M group of samples after electron irradiation; Step S5, determining the optimal cumulative injection amount for improving the performance of the silicon carbide semiconductor detector: Extract the relationship between the performance index of group M irradiated samples and the cumulative dose, and determine the optimal cumulative dose D B ; Step S6, electron irradiation is performed on the silicon carbide semiconductor detector whose performance is to be improved: Among the silicon carbide semiconductor detectors that have not failed, N are randomly selected and the remaining silicon carbide semiconductor detectors are selected according to the determined optimal cumulative injection amount D B Electron irradiation is performed to obtain a silicon carbide semiconductor detector with improved performance.

[0006] In the above-mentioned method for improving the performance of silicon carbide semiconductor detectors based on electron irradiation, in step S1, the electrical performance test includes a forward voltage-current characteristic curve test and a reverse voltage-current characteristic curve test, and the scanning voltage range of the forward voltage-current characteristic curve test is 0-2 V, with a step size of 0.1 V; the scanning voltage range of the reverse voltage-current characteristic curve test is 0-500 V, with a step size of 50 V.

[0007] In the above-mentioned method for improving the performance of silicon carbide semiconductor detectors based on electron irradiation, in the step S1, the test system for the alpha particle amplitude spectrum response test includes a vacuum chamber, a high-voltage power supply, a computer and an ORTEC nuclear electronics plug-in, the silicon carbide semiconductor detector is placed in the vacuum chamber, the high-voltage power supply is electrically connected to the silicon carbide semiconductor detector, the ORTEC nuclear electronics plug-in includes a preamplifier, a main amplifier and a multi-channel analyzer, the signal output end of the silicon carbide semiconductor detector is connected to the computer after passing through the preamplifier, the main amplifier and the multi-channel analyzer in sequence, and an alpha isotope radiation source is set in the vacuum chamber. In the above-mentioned method for improving the performance of silicon carbide semiconductor detectors based on electron irradiation, in the step S1, the alpha isotope radiation source is 241 Am, 243 Am, 244 Cm, 238 Pu, 239 One of Pu.

[0008] In the above-mentioned method for improving the performance of silicon carbide semiconductor detectors based on electron irradiation, in step S1, the performance indicators include forward turn-on voltage, dark current, charge collection efficiency and energy resolution, the forward turn-on voltage is extracted from the forward voltage-current characteristic curve, the dark current is extracted from the reverse voltage-current characteristic curve, and the charge collection efficiency and energy resolution are extracted from the alpha particle amplitude spectrum response test.

[0009] In the above-mentioned method for improving the performance of silicon carbide semiconductor detectors based on electron irradiation, in step S1, a current density of 1 A / cm is extracted from the forward voltage-current characteristic curve of the irradiated sample. 2 The corresponding voltage is the forward turn-on voltage. V on ; From the reverse voltage-current characteristic curve of the irradiated sample, the current of the silicon carbide semiconductor detector in the reverse electric field strength range of 0~4 V / μm is extracted as the dark current.

[0010] In the above-mentioned method for improving the performance of silicon carbide semiconductor detectors based on electron irradiation, in step S1, the calculation formula for extracting the charge collection efficiency CCE from the α-particle amplitude spectrum response test is as follows: In the formula, ω SiC is the average ionization energy of silicon carbide material, ω Si is the average ionization energy of silicon material, P SiC It is the center address of the α-particle amplitude spectrum peak of the silicon carbide semiconductor detector. P Si It is the center address of the alpha particle amplitude spectrum peak of a reference silicon detector with a charge collection efficiency of 100% under exactly the same measurement conditions.

[0011] In the above-mentioned method for improving the performance of silicon carbide semiconductor detectors based on electron irradiation, in step S1, the calculation formula for extracting the energy resolution ER from the α-particle amplitude spectrum response test is as follows:

[0012] In the formula, FWHM is the half-height width of the alpha particle amplitude spectrum peak of the silicon carbide semiconductor detector.

[0013] In the above-mentioned method for improving the performance of silicon carbide semiconductor detectors based on electron irradiation, in step S3, the cumulative electron irradiation dose range is 1×10 16 / cm 2 ~ 1×10 17 / cm 2 .

[0014] In the above-mentioned method for improving the performance of silicon carbide semiconductor detectors based on electron irradiation, in step S5, the method for determining the optimal cumulative injection amount is as follows: the first step is to determine the forward turn-on voltage of all samples with M different cumulative injection amounts. V on , the forward turn-on voltage after irradiation V onThe samples with a variation greater than or equal to 20% are removed to obtain the first remaining samples; The second step is to determine the energy resolution of the samples in the first remaining sample, and remove the samples whose energy resolution decreases by less than 20% after irradiation to obtain the second remaining sample; The third step is to determine the dark current of the samples in the second remaining sample, and remove the samples whose dark current increase after irradiation is greater than or equal to 10%, to obtain the third remaining sample; The fourth step is to determine the charge collection efficiency of the samples in the third remaining sample, and remove the samples whose charge collection efficiency decreases by more than 10% after irradiation to obtain the fourth remaining sample; The fifth step is to determine the energy resolution of the samples in the fourth remaining sample, and to use the cumulative injection amount used for the sample with the lowest energy resolution decrease after irradiation as the optimal cumulative injection amount.

[0015] The beneficial effects of the present invention are as follows: the present invention utilizes electron irradiation, which can greatly improve the performance without changing the original design of the silicon carbide semiconductor detector, has little effect on the forward characteristics of the silicon carbide semiconductor detector, can effectively improve the dark current, charge collection efficiency and energy resolution of the silicon carbide semiconductor detector, and is not limited by the manufacturing process flow, can be implemented before or after the silicon carbide semiconductor detector is packaged, has a simple process, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a flow chart of the present invention.

[0017] Figure 2 It is a schematic diagram of the alpha particle amplitude spectrum response test principle of the present invention.

[0018] Figure 3 This is a diagram of the dark current optimization effect of the silicon carbide semiconductor detector after electron irradiation.

[0019] Figure 4 This is a diagram showing the optimization effect of charge collection efficiency of silicon carbide semiconductor detectors after electron irradiation.

[0020] Figure 5 This is a diagram showing the energy resolution optimization effect of a silicon carbide semiconductor detector after electron irradiation. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0022] like Figure 1 As shown, a method for improving the performance of a silicon carbide semiconductor detector based on electron irradiation comprises the following steps: Step S1, selecting a silicon carbide semiconductor detector: Conduct electrical performance tests and alpha particle amplitude spectrum response tests on the silicon carbide semiconductor detectors whose performance needs to be improved to obtain the initial performance indicators of the silicon carbide semiconductor detectors, eliminate failed silicon carbide semiconductor detectors with abnormal performance indicators, and retain intact silicon carbide semiconductor detectors.

[0023] The electrical performance test includes forward voltage-current characteristic curve test and reverse voltage-current characteristic curve test. The scanning voltage range of the forward voltage-current characteristic curve test is 0~2 V with a step size of 0.1 V; the scanning voltage range of the reverse voltage-current characteristic curve test is 0~500 V with a step size of 50 V.

[0024] like Figure 2 As shown, the test system for the alpha particle amplitude spectrum response test includes a vacuum chamber 1, a high voltage power supply, a computer and an ORTEC nuclear electronics plug-in 3. The silicon carbide semiconductor detector is placed in the vacuum chamber 1. The high voltage power supply is electrically connected to the silicon carbide semiconductor detector. The ORTEC nuclear electronics plug-in 3 includes a preamplifier ORTEC142A, a main amplifier ORTEC672 and a multi-channel analyzer ORTEC927. The signal output end of the silicon carbide semiconductor detector is connected to the computer after passing through the preamplifier, the main amplifier and the multi-channel analyzer in sequence. An alpha isotope radiation source 2 is set in the vacuum chamber 1. The alpha isotope radiation source 2 is 241 Am, 243 Am, 244 Cm, 238 Pu, 239 One of Pu.

[0025] The performance indicators include forward turn-on voltage, dark current, charge collection efficiency and energy resolution. The forward turn-on voltage is extracted from the forward voltage-current characteristic curve, the dark current is extracted from the reverse voltage-current characteristic curve, and the charge collection efficiency and energy resolution are extracted from the alpha particle amplitude spectrum response test.

[0026] From the forward voltage-current characteristic curve of the irradiated sample, the current density was extracted to be 1 A / cm 2 The corresponding voltage is the forward turn-on voltage. V on ; From the reverse voltage-current characteristic curve of the irradiated sample, the current of the silicon carbide semiconductor detector in the reverse electric field strength range of 0~4 V / μm is extracted as the dark current.

[0027] The calculation formula for extracting the charge collection efficiency CCE from the alpha particle amplitude spectrum response test is as follows: In the formula, ω SiC is the average ionization energy of silicon carbide material, ωSi is the average ionization energy of silicon material, P SiC It is the center address of the α-particle amplitude spectrum peak of the silicon carbide semiconductor detector. P Si It is the center address of the alpha particle amplitude spectrum peak of a reference silicon detector with a charge collection efficiency of 100% under exactly the same measurement conditions.

[0028] The calculation formula for extracting the energy resolution ER from the alpha particle amplitude spectrum response test is as follows:

[0029] In the formula, FWHM is the half-height width of the alpha particle amplitude spectrum peak of the silicon carbide semiconductor detector.

[0030] Step S2, grouping silicon carbide semiconductor detectors: N intact silicon carbide semiconductor detectors are randomly selected as samples and divided into M groups.

[0031] Step S3, electron irradiation of the sample: The selected M groups of samples are subjected to electron irradiation with M different cumulative injection doses, and each group of samples uses the same cumulative injection dose.

[0032] The cumulative electron irradiation dose range is 1×10 16 / cm 2 ~ 1×10 17 / cm 2 .

[0033] Step S4, testing the performance of the sample after electron irradiation: The electrical performance test and alpha particle amplitude spectrum response test are performed on the M group of electron-irradiated samples, and the test condition parameters are the same as the test condition parameters in step S1 to obtain the performance indicators of the M group of samples after electron irradiation.

[0034] Step S5, determining the optimal cumulative injection amount for improving the performance of the silicon carbide semiconductor detector: Extract the relationship between the performance index of group M irradiated samples and the cumulative dose, and determine the optimal cumulative dose D B .

[0035] The method to determine the optimal cumulative fluence is: The first step is to determine the forward turn-on voltage of all samples with M different cumulative injection amounts. V on , the forward turn-on voltage after irradiation V on The samples with a variation greater than or equal to 20% are removed to obtain the first remaining samples; The second step is to determine the energy resolution of the samples in the first remaining sample, and remove the samples whose energy resolution decreases by less than 20% after irradiation to obtain the second remaining sample; The third step is to determine the dark current of the samples in the second remaining sample, and remove the samples whose dark current increase after irradiation is greater than or equal to 10%, to obtain the third remaining sample; The fourth step is to determine the charge collection efficiency of the samples in the third remaining sample, and remove the samples whose charge collection efficiency decreases by more than 10% after irradiation to obtain the fourth remaining sample; The fifth step is to determine the energy resolution of the samples in the fourth remaining sample, and to use the cumulative injection amount used for the sample with the lowest energy resolution decrease after irradiation as the optimal cumulative injection amount.

[0036] Step S6, electron irradiation is performed on the silicon carbide semiconductor detector whose performance is to be improved: Among the silicon carbide semiconductor detectors that have not failed, N are randomly selected and the remaining silicon carbide semiconductor detectors are selected according to the determined optimal cumulative injection amount D B Electron irradiation is performed to obtain a silicon carbide semiconductor detector with improved performance.

[0037] like Figure 3 As shown, the dark current level of the SiC semiconductor detector with improved performance obtained by the present invention is significantly reduced in the reverse electric field strength range of 0-4V / μm, especially with the increase of the reverse electric field strength, the dark current reduction amplitude gradually increases.

[0038] like Figure 4 As shown, the charge collection efficiency of the SiC semiconductor detector with improved performance obtained by the present invention is significantly improved in the reverse electric field strength range of 0.2~1.4 V / μm, especially in the range of 0.4~1.0 V / μm, the charge collection efficiency of the SiC semiconductor detector is improved from less than 10% to more than 60%.

[0039] like Figure 5 As shown, the energy resolution value of the SiC semiconductor detector with improved performance obtained by the present invention is significantly reduced in the reverse electric field strength range of 1.5~3.0 V / μm, and the energy resolution decreases by about 25% in the reverse electric field strength range of 1.5~2.0 V / μm, indicating that the energy resolution of the SiC semiconductor detector is improved.

Claims

1. A method for improving the performance of a silicon carbide semiconductor detector based on electron irradiation, characterized in that: The following steps are involved: Step S1, selecting a silicon carbide semiconductor detector: Conduct electrical performance tests and alpha particle amplitude spectrum response tests on the silicon carbide semiconductor detectors whose performance needs to be improved, obtain the initial performance indicators of the silicon carbide semiconductor detectors, eliminate the failed silicon carbide semiconductor detectors with abnormal performance indicators, and retain the silicon carbide semiconductor detectors that have not failed; Step S2, grouping silicon carbide semiconductor detectors: Randomly select N non-failed silicon carbide semiconductor detectors as samples and divide them into M groups; Step S3, electron irradiation of the sample: The selected M groups of samples are subjected to electron irradiation with M different cumulative injection doses, and each group of samples adopts the same cumulative injection dose; Step S4, testing sample performance after electron irradiation: Conducting electrical performance test and alpha particle amplitude spectrum response test on the M group of electron-irradiated samples, with the test condition parameters being the same as the test condition parameters in step S1, to obtain the performance indicators of the M group of samples after electron irradiation; Step S5, determining the optimal cumulative injection amount for improving the performance of the silicon carbide semiconductor detector: Extract the relationship between the performance index of group M irradiated samples and the cumulative dose, and determine the optimal cumulative dose D B ; Step S6, electron irradiation is performed on the silicon carbide semiconductor detector whose performance is to be improved: Among the silicon carbide semiconductor detectors that have not failed, N are randomly selected and the remaining silicon carbide semiconductor detectors are selected according to the determined optimal cumulative injection amount D B Electron irradiation is performed to obtain a silicon carbide semiconductor detector with improved performance.

2. The method for improving the performance of silicon carbide semiconductor detectors based on electron irradiation according to claim 1, characterized in that: In step S1, the electrical performance test includes a forward voltage-current characteristic curve test and a reverse voltage-current characteristic curve test. The scanning voltage range of the forward voltage-current characteristic curve test is 0-2 V, with a step size of 0.1 V; the scanning voltage range of the reverse voltage-current characteristic curve test is 0-500 V, with a step size of 50 V.

3. The method for improving the performance of silicon carbide semiconductor detectors based on electron irradiation according to claim 1, characterized in that: In the step S1, the test system for the alpha particle amplitude spectrum response test includes a vacuum chamber, a high voltage power supply, a computer and an ORTEC nuclear electronics plug-in, a silicon carbide semiconductor detector is placed in the vacuum chamber, the high voltage power supply is electrically connected to the silicon carbide semiconductor detector, the ORTEC nuclear electronics plug-in includes a preamplifier, a main amplifier and a multi-channel analyzer, the signal output end of the silicon carbide semiconductor detector is connected to the computer after passing through the preamplifier, the main amplifier and the multi-channel analyzer in sequence, and an alpha isotope radiation source is arranged in the vacuum chamber.

4. The method for improving the performance of silicon carbide semiconductor detectors based on electron irradiation according to claim 3, characterized in that: In step S1, the α isotope radiation source is 241 Am, 243 Am, 244 Cm, 238 Pu, 239 One of Pu.

5. The method for improving the performance of silicon carbide semiconductor detectors based on electron irradiation according to claim 1, characterized in that: In step S1, the performance indicators include forward turn-on voltage, dark current, charge collection efficiency and energy resolution. The forward turn-on voltage is extracted from the forward voltage-current characteristic curve, the dark current is extracted from the reverse voltage-current characteristic curve, and the charge collection efficiency and energy resolution are extracted from the alpha particle amplitude spectrum response test.

6. The method for improving the performance of silicon carbide semiconductor detectors based on electron irradiation according to claim 5, characterized in that: In step S1, the current density of 1 A / cm is extracted from the forward voltage-current characteristic curve of the irradiated sample. 2 The corresponding voltage is the forward turn-on voltage. V on ; From the reverse voltage-current characteristic curve of the irradiated sample, the current of the silicon carbide semiconductor detector in the reverse electric field strength range of 0~4 V / μm is extracted as the dark current.

7. The method for improving the performance of silicon carbide semiconductor detectors based on electron irradiation according to claim 6, characterized in that: In step S1, the calculation formula for extracting the charge collection efficiency CCE from the α-particle amplitude spectrum response test is as follows: ； In the formula, ω SiC is the average ionization energy of silicon carbide material, ω Si is the average ionization energy of silicon material, P SiC It is the center address of the α-particle amplitude spectrum peak of the silicon carbide semiconductor detector. P Si It is the center address of the alpha particle amplitude spectrum peak of a reference silicon detector with a charge collection efficiency of 100% under exactly the same measurement conditions.

8. The method for improving the performance of silicon carbide semiconductor detectors based on electron irradiation according to claim 5, characterized in that: In step S1, the calculation formula for extracting the energy resolution ER from the α-particle amplitude spectrum response test is as follows: ； In the formula, FWHM is the half-height width of the alpha particle amplitude spectrum peak of the silicon carbide semiconductor detector.

9. The method for improving the performance of silicon carbide semiconductor detectors based on electron irradiation according to claim 1, characterized in that: In step S3, the cumulative electron irradiation dose range is 1×10 16 / cm 2 ~ 1×10 17 / cm 2 .

10. The method for improving the performance of silicon carbide semiconductor detectors based on electron irradiation according to claim 1, characterized in that: In step S5, the method for determining the optimal cumulative fluence is: The first step is to determine the forward turn-on voltage of all samples with M different cumulative injection amounts. V on , the forward turn-on voltage after irradiation V on The samples with a variation greater than or equal to 20% are removed to obtain the first remaining samples; The second step is to determine the energy resolution of the samples in the first remaining sample, and remove the samples whose energy resolution decreases by less than 20% after irradiation to obtain the second remaining sample; The third step is to determine the dark current of the samples in the second remaining sample, and remove the samples whose dark current increase after irradiation is greater than or equal to 10%, to obtain the third remaining sample; The fourth step is to determine the charge collection efficiency of the samples in the third remaining sample, and remove the samples whose charge collection efficiency decreases by more than 10% after irradiation to obtain the fourth remaining sample; The fifth step is to determine the energy resolution of the samples in the fourth remaining sample, and to use the cumulative injection amount used for the sample with the lowest energy resolution decrease after irradiation as the optimal cumulative injection amount.

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