Method for relieving electric leakage degradation effect of GaN device
By performing neutron radiation treatment on GaN devices, optimizing their structure and electrical characteristics, the problem of leakage degradation effect is solved, the stability and reliability of the device in a high-radiation environment is improved, and the industry standards are met and leakage current growth is reduced.
Patent Information
- Application Number
- CN202510231670.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-28
- Publication Date
- 2025-07-11
AI Technical Summary
GaN devices are prone to leakage degradation effects in high-radiation environments, resulting in performance degradation and reliability problems, especially in applications such as aerospace and nuclear energy.
By irradiating GaN devices with neutrons, introducing appropriate defects to optimize their anti-leaved degradation performance, a combination of simulation and experiments is used to determine appropriate neutron irradiation conditions, and optimize the device structure and electrical characteristics.
It significantly improves the stability and reliability of GaN devices in high-radiation environments, meets the requirements of electrical performance derating of industry standards, reduces the increase in leakage current, and improves the ability to resist leakage degradation.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of power semiconductor devices, and in particular to a method for alleviating the leakage degradation effect of a GaN device. Background Art
[0002] As the third generation wide bandgap semiconductor material, gallium nitride (GaN) has become a key material for modern electronic technology due to its excellent electrical properties, such as high saturated electron mobility, high breakdown voltage, wide bandgap characteristics, and excellent high frequency and high power characteristics. It is expected to be widely used in aerospace, satellite communications, power supply systems and other application fields. However, unlike the ground environment, GaN devices need to face the challenges of various radiation effects in the space environment, which will cause the performance of the device to degrade or even be damaged.
[0003] Among the many radiation effects, leakage degradation effect is a newly discovered radiation damage mode in recent years. Different from traditional radiation effects (such as displacement damage effect, total dose effect, etc.), leakage degradation effect is currently only observed in wide bandgap semiconductor devices (such as SiC, GaN devices), which limits the application of wide bandgap devices in radiation environments. Leakage degradation effect refers to the phenomenon that when the drain-source voltage V DS After increasing to a certain value, high-energy particle irradiation will form a leakage channel inside the GaN device, causing the leakage current to continue to rise, and the GaN device will enter the leakage degradation zone. This not only affects the working efficiency of the GaN device, but may also cause energy loss and heat accumulation at high frequency and high power, thereby reducing the overall performance of the system. For example, the increase in leakage current not only leads to a decrease in switching efficiency, but also prolongs the response time of the GaN device, increases switching losses and reduces energy efficiency, especially in high-frequency applications. At the same time, due to the limitation of thermal management capabilities, the increase in leakage current will cause the GaN device to generate too much heat, which may cause thermal runaway and even burn the GaN device, seriously affecting its long-term reliability. With the accumulation of radiation damage, the breakdown voltage of the GaN device may decrease, making the GaN device more likely to break down when subjected to higher voltages, further threatening the safety of the GaN device and the system. It can be seen that the radiation-induced leakage degradation effect poses a huge threat to the normal operation and reliability of GaN devices, especially when used in high-radiation environments such as aerospace and nuclear energy, which may lead to catastrophic consequences. Therefore, how to effectively alleviate the leakage degradation phenomenon caused by radiation has become an urgent problem to be solved in the current radiation resistance field. Summary of the invention
[0004] Technical problem to be solved: Aiming at the technical problems existing in the GaN device during operation in a high-radiation environment in the background art, the present invention provides a method for alleviating the leakage degradation effect of the GaN device, aiming to introduce an appropriate amount of defects into the GaN device by neutron irradiation, thereby optimizing the anti-leakage degradation performance of the GaN device; this method can significantly improve the stability and reliability of the GaN device in a high-radiation environment, thereby ensuring its long-term reliable operation in aerospace and other key fields.
[0005] Technical solution: A method for alleviating the leakage degradation effect of the GaN device described in the present invention, the method includes the following steps: Step 1: Select the type of GaN device that needs to optimize the anti-leakage degradation performance, and establish a two-dimensional structural model of the GaN device in TCAD according to the structural parameters of the selected GaN device; Step 2: Select a physical model and calculation method to obtain the electrical characteristics of the GaN device, and then optimize the electrical characteristics of the GaN device to be consistent with the standard values in the GaN device manual by adjusting the doping concentration and structural size parameters of the GaN device; Step 3: Perform neutron irradiation simulation on the optimized GaN device, and calculate the defect information generated in the GaN device during neutron irradiation by adding relevant models of displacement damage; Step 4: Change the fluence of neutron irradiation to obtain the electrical characteristic curves under different irradiation fluences, and select the electrical parameter that is the most sensitive to changes as the standard for evaluating the performance degradation of the GaN device after neutron irradiation; Step 5: Compare the change amplitudes of the sensitive parameters under different irradiation fluences, and determine the minimum fluence F MIN and the maximum fluence F MAX of neutron irradiation corresponding to the degradation value of the sensitive parameter; Step 6: Select qualified GaN device samples for electrical parameter testing, and conduct neutron irradiation tests on the GaN devices; among them, the neutron irradiation fluence is selected as a certain value between F MIN and F MAX ; Step 7: Stop neutron irradiation when the neutron irradiation fluence reaches the preset fluence, and complete the optimization of the anti-leakage degradation performance of the GaN device.
[0006] Preferably, in step 3, when alleviating the leakage degradation of the GaN device, the range of the neutron irradiation energy E is between 1 and 10 MeV.
[0007] Preferably, the minimum fluence F MIN of neutron irradiation in step 5 corresponds to a 10% degradation value of the sensitive parameter, and the maximum fluence F MAX of neutron irradiation corresponds to a 20% degradation value of the sensitive parameter.
[0008] Preferably, after the residual neutron irradiation dose reaches the safety value, the optimized GaN device completed in step 7 is tested for electrical performance, and whether the degradation value of the electrical characteristics before and after neutron irradiation meets the derating requirements is compared, and the data is saved.
[0009] Preferably, an irradiation test is performed on the GaN device treated by neutron irradiation to check whether the anti-leakage degradation performance of the GaN device is improved.
[0010] Compared with the prior art, the present invention has at least the following beneficial effects: 1. The present invention innovatively proposes a method to alleviate the leakage degradation effect of GaN devices. It can not only avoid modifying the layout design and processing technology of GaN devices, but also does not require adding additional anti-irradiation circuits. Only by determining appropriate neutron irradiation conditions and performing neutron pre-irradiation tests on GaN devices can the anti-leakage degradation performance of GaN devices be improved; 2. This method combines simulation and experiment to systematically determine the neutron irradiation conditions suitable for optimizing the anti-leakage degradation performance. This method is simple to operate, highly reliable, and effectively reduces the experimental cost through simulation. It not only improves the R & D efficiency, but also ensures the accuracy and repeatability of the experimental results, having good economic and technical advantages; 3. This method pre-treats GaN devices through irradiation, can simultaneously optimize the anti-leakage degradation performance of a large number of GaN devices, and does not limit the type of GaN devices, having good convenience and universality; 4. After the GaN device of the present invention is treated by neutron irradiation, the electrical performance degradation does not exceed 20% at most, meeting the requirements of the maximum derating in the industry standard, and its anti-leakage degradation ability is significantly improved. Even under high LET heavy ion irradiation, the growth rate of the leakage current is significantly reduced, fully demonstrating the superiority and effectiveness of this technology. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 It is a schematic diagram of the optimization process for alleviating the leakage degradation effect of GaN devices of the present invention; Figure 2 It is a schematic diagram of the structure of a P-type gate GaN HEMT device ((a) GaN device cell structure; (b) TCAD simulation two-dimensional structure of GaN device); Figure 3 It is the electrical characteristic curve after the optimization of the GaN device model ((a) Transfer characteristic curve of GaN device; (b) Breakdown characteristic curve of GaN device); Figure 4 It is the graph of the change relationship between I DS and V TH with the irradiation fluence after 2.5 MeV neutron irradiation; Figure 5 For the comparison chart of the electrical characteristic curves of the GaN device before and after 2.5 MeV neutron irradiation with a fluence of 1.8×10 10 n / cm 2 ((a) Transfer characteristic curves before and after neutron irradiation; (b) Output characteristic curves before and after neutron irradiation); Figure 6 For the original data chart of the leakage degradation of the GaN device before and after neutron irradiation ((a) The I D original data of the GaN device before neutron irradiation; (b) The I D original data of the GaN device after neutron irradiation); Figure 7 For the curve of the leakage rate of the GaN device after neutron irradiation and the non-irradiated GaN device varying with V DS ((a) I D linear fitting chart; (b) Comparison chart of leakage rates). Specific implementation manners
[0012] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying Figures 1 to 7 drawings. Obviously, the described embodiments are some, rather than all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention fall within the scope of protection of the present invention.
[0013] As Figure 1 shown, the present invention discloses a method for alleviating the leakage degradation effect of a GaN device. The method includes the following steps: (1) Select the type of GaN device that needs to optimize the anti-leakage degradation performance. For example, a P-type gate GaN HEMT device independently developed by a certain research institute is adopted. Its package form is TO-254 package, the threshold voltage V TH is 1.8 V, and the rated voltage V DSS is 650 V. Its GaN device cell structure is as Figure 2 (a) shown. According to the structural parameters of the selected GaN device, a two-dimensional structure model of the GaN device is established in TCAD, and its structure is as Figure 2 (b) shown.
[0014] (2) Select a physical model and a calculation method to obtain the electrical characteristics of the GaN device; among them, the selected physical models include a mobility model, a carrier statistics model, a recombination model, a polarization model, etc.; the selected calculation method is the Newton iteration method. Then, by adjusting the doping concentration and structural dimension parameters of the GaN device, the electrical characteristics of the GaN device are optimized to be consistent with the standard values in the GaN device manual. The electrical characteristic curves of the optimized GaN device are asFigure 3 as shown
[0015] (3) Perform neutron irradiation simulation on the optimized GaN device. By adding relevant models of displacement damage, calculate the defect information generated in the GaN device during neutron irradiation. To ensure that neutrons can effectively penetrate the GaN device, high-energy neutrons with an energy higher than 1 MeV should be selected for irradiation; when the neutron irradiation energy is higher than 10 MeV, the non-ionizing energy deposition is small, which is likely to trigger the single-event effect of the GaN device. When alleviating the leakage degradation of the GaN device, the range of neutron irradiation energy E is between 1 MeV and 10 MeV. In a specific embodiment, the neutron irradiation energy E = 2.5 MeV is selected.
[0016] (4) Change the fluence of neutron irradiation to obtain the electrical characteristic curves under different irradiation fluences, and select the electrical parameter that is most sensitive to changes as the standard for evaluating the performance degradation of the GaN device after neutron irradiation. As Figure 4 shown, observe the main electrical characteristic degradation of the GaN device after neutron irradiation, and obtain that the degradation amplitude of the output saturation drain current I DS is larger than that of the threshold voltage V TH . Therefore, the output saturation drain current I DS is selected as the standard for evaluating the electrical performance degradation of the GaN device.
[0017] (5) Compare the change amplitudes of sensitive parameters under different irradiation fluences, and determine the minimum fluence F MIN and the maximum fluence F MAX of neutron irradiation corresponding to the degradation value of the sensitive parameter. Compare the change amplitudes of sensitive parameters under different neutron irradiation fluences. It is considered that when the degradation amplitude of this parameter exceeds 10%, enough defects are introduced into the GaN device. Take the irradiation fluence corresponding to a 10% degradation of the sensitive parameter as the minimum fluence F MIN to alleviate the leakage degradation effect of the GaN device; according to the regulations in the NASA document "Instructions for EEE Parts Selection, Screening, Qualification, and Derating" (EEE-INST-002), for electronic components applied in spacecraft, the derating of most performance parameters shall not exceed 20%. Take the neutron irradiation fluence corresponding to a 20% degradation of the sensitive parameter as the maximum fluence F MAX to alleviate the leakage degradation effect of the GaN device.
[0018] In a specific embodiment, when the neutron irradiation fluence is between 1×10 10 n / cm 2 and 3×10 10 n / cm 2 , the drain current IDS The degradation range is between 10% and 20%. Therefore, in the 2.5 MeV neutron irradiation test, the minimum fluence F MIN is 1×10 10 n / cm 2 , and the maximum fluence F MAX is 3×10 10 n / cm 2 .
[0019] (VI) Select qualified GaN device samples for electrical parameter testing and conduct neutron irradiation tests on GaN devices; among them, the neutron irradiation fluence is selected as a certain value between F MIN and F MAX . Conduct a monoenergetic neutron irradiation test with an energy of 2.5 MeV on the screened qualified GaN devices. The total fluence of neutron irradiation is selected as 1.8×10 10 n / cm 2 . When neutron irradiating the GaN devices, the three-terminal electrodes of the GaN devices are suspended. The test environmental temperature is room temperature, and the neutrons are incident perpendicularly on the GaN devices.
[0020] (VII) When the neutron irradiation fluence reaches the preset fluence, stop neutron irradiation to complete the optimization of the anti-leakage degradation performance of the GaN devices; after the residual neutron irradiation dose reaches the safe value, conduct electrical performance tests on the optimized GaN devices, compare whether the degradation values of the electrical characteristics before and after neutron irradiation meet the derating requirements, and save the data. Conduct electrical performance tests on the GaN devices. Comparison diagrams of the transfer characteristic curves and output characteristic curves of the GaN devices before and after neutron irradiation (as Figure 5 shown). As can be seen from Figure 5 , after neutron irradiation, the output saturation drain current I DS of the GaN devices decreases by 14.1%, meeting the requirements of the maximum derating in the GaN device industry standard.
[0021] (VIII) Conduct irradiation tests on the neutron-irradiated GaN devices to verify whether the anti-leakage degradation performance of the GaN devices has been improved. To verify the improvement of the anti-leakage degradation ability of the GaN devices after neutron irradiation, conduct heavy ion irradiation tests on the GaN devices. The ion type is Ta ions, the ion energy is 1332.16 MeV, and the LET is 82.1 MeV•cm 2 / mg. When heavy ion irradiating the GaN devices, the GaN devices are in the off state. The test environmental temperature is room temperature, and the particles are incident perpendicularly on the surface of the GaN devices.
[0022] Use unirradiated GaN devices with good electrical performance as the control group and conduct heavy ion irradiation tests on them. During the test process, slowly increase V DS to cause leakage degradation of the GaN devices and observe the change of the leakage current I D of the GaN devices, VDS Stop irradiation after reaching 280V. Figure 6 (a) is the original data graph of the leakage degradation of the GaN device without neutron irradiation; from Figure 6 (a), it can be seen that the leakage current I of the GaN device D gradually increases with the increase of the heavy ion irradiation fluence, and the final leakage current I at 280V D is 25.5 μA, and the total irradiation fluence is 6.4×10 6 / cm 2 .
[0023] Take the GaN device after 2.5MeV neutron irradiation as the experimental group, conduct heavy ion irradiation experiments on it, and observe the leakage degradation phenomenon during the heavy ion irradiation process. Figure 6 (b) is the original data graph of the leakage degradation of the GaN device after 2.5MeV neutron irradiation; from Figure 6 (b), it can be seen that the leakage current I of the GaN device D gradually increases with the increase of the irradiation fluence, and the final leakage current I at 300V D is 18.3 μA, and the total irradiation fluence is 8.5×10 6 / cm 2 .
[0024] Analyze and compare the final leakage current I of the control group and the experimental group D , under the conditions that the GaN device after 2.5MeV neutron irradiation experiences more heavy ion irradiation fluence and bears a greater drain voltage V DS , the final leakage current I D is actually smaller than that of the GaN device without neutron irradiation, indicating that the anti-leakage degradation ability of the GaN device after neutron irradiation treatment is enhanced.
[0025] According to the existing research, under the same V DS condition, the leakage current I when the GaN device undergoes leakage degradation D is linearly related to the irradiation fluence. Linear fitting is performed on the leakage current I DS and the fluence under the same V D , and the slope of the straight line obtained by fitting is named "leakage rate" r. The change curve of the leakage rate r of the GaN device before and after neutron irradiation with V DS is obtained (as shown in Figure 7 ), from Figure 7 (b), it can be seen that after entering the leakage degradation region, under the same V DS condition, the leakage rate r irradiated of the GaN device experiencing neutron irradiation is pristine smaller than the leakage rate r DSdecreases by approximately 90% when = 240V, indicating that at the same neutron irradiation fluence, the leakage current I generated by the GaN device after neutron irradiation is D less than the leakage current I of the non-irradiated GaN device, D that is, the leakage degradation effect is effectively alleviated. In summary, the embodiments of the present invention show that at a fluence of 1.8×10 10 n / cm 2 the 2.5MeV neutron irradiation can effectively alleviate the leakage degradation effect of P-type gate GaN HEMT devices and improve the anti-leakage degradation ability of GaN devices.
[0026] The present invention innovatively proposes a method for alleviating the leakage degradation effect of GaN devices. It can not only avoid modifying the layout design and processing technology of GaN devices, but also does not require adding additional anti-irradiation circuits. Only by determining appropriate neutron irradiation conditions and conducting neutron pre-irradiation tests on GaN devices can the anti-leakage degradation performance of GaN devices be improved. This method combines simulation and experiment to systematically determine the neutron irradiation conditions suitable for optimizing the anti-leakage degradation performance. This method is easy to operate, highly reliable, and effectively reduces the experimental cost through simulation. It not only improves the R & D efficiency but also ensures the accuracy and repeatability of experimental results, having good economic and technical advantages. This method can pre-treat GaN devices through irradiation, simultaneously optimize the anti-leakage degradation performance of a large number of GaN devices, and is not limited to the type of GaN devices, having good convenience and universality. After neutron irradiation treatment, the electrical performance degradation of the GaN devices of the present invention is at most no more than 20%, meeting the requirements of the maximum derating in industry standards, while their anti-leakage degradation ability is significantly improved. Even under high-LET heavy ion irradiation, the increase in leakage current is significantly reduced, fully demonstrating the superiority and effectiveness of this technology.
[0027] The above are the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.
Claims
1. A method for alleviating the leakage degradation effect of GaN devices, characterized in that, The method includes the following steps: Step 1: Select the type of GaN device that needs to optimize the anti-leakage degradation performance. According to the structural parameters of the selected GaN device, establish a two-dimensional structural model of the GaN device in TCAD; Step 2: Select the physical model and calculation method to obtain the electrical characteristics of the GaN device. Then, by adjusting the doping concentration and structural size parameters of the GaN device, optimize the electrical characteristics of the GaN device to be consistent with the standard values in the GaN device manual; Step 3: Perform neutron irradiation simulation on the optimized GaN device. By adding relevant models of displacement damage, calculate the defect information generated in the GaN device during neutron irradiation; Step 4: Change the neutron irradiation fluence, obtain the electrical characteristic curves under different irradiation fluences, and select the electrical parameter that is most sensitive to the change as the standard for evaluating the performance degradation of the GaN device after neutron irradiation; Step 5: Compare the variation ranges of sensitive parameters at different irradiation fluences, and determine the minimum fluence F MIN and the maximum fluence F MAX ; Step 6: Select qualified GaN device samples for electrical parameter testing and conduct neutron irradiation tests on the GaN devices; among them, the neutron irradiation fluence is selected as a certain value between F MIN ~F MAX ; Step 7: Stop neutron irradiation when the neutron irradiation fluence reaches the preset fluence, and complete the optimization of the anti-leakage degradation performance of the GaN device.
2. The method for alleviating the leakage degradation effect of GaN devices according to claim 1, wherein, In step 3, the range of the neutron irradiation energy E for alleviating the leakage degradation of the GaN device is between 1 and 10 MeV.
3. The method for alleviating the leakage degradation effect of GaN devices according to claim 1, wherein The minimum fluence F of neutron irradiation in step 5 MIN corresponding to a 10% degradation value of the sensitive parameter, the maximum fluence F of neutron irradiation MAX corresponding to a 20% degradation value of the sensitive parameter.
4. The method for alleviating the leakage degradation effect of GaN devices according to claim 1, wherein After the residual neutron irradiation dose reaches the safety value, perform electrical performance tests on the GaN device optimized in step 7, compare whether the electrical characteristic degradation values before and after neutron irradiation meet the derating requirements, and save the data.
5. The method for alleviating the leakage degradation effect of GaN devices according to claim 4, characterized in that, Perform irradiation tests on the GaN device treated by neutron irradiation to check whether the anti-leakage degradation performance of the GaN device is improved.