Simulation method for ionization / displacement synergistic effect in bipolar transistor oxide layer

Abstract

The application relates to the technical field of simulation analog of electronic devices, and relates to a simulation method for ionization / displacement synergistic effect in an oxide layer of a bipolar transistor, which comprises the following steps: constructing an oxide layer model of the bipolar transistor; obtaining an ionization radiation effect defect model after the oxide layer model of the bipolar transistor interacts with high-energy photons to generate ionization radiation effect; obtaining a displacement radiation effect defect model after a charged particle interacts with the oxide layer model of the bipolar transistor to generate displacement radiation effect, and calculating a second defect parameter of the displacement radiation effect defect model by using SRIM software; inputting the first defect parameter and the second defect parameter into the ionization radiation effect defect model after the first defect parameter and the second defect parameter are associated, obtaining an ionization / displacement synergistic effect defect model, and obtaining a third defect parameter of the ionization / displacement synergistic effect defect model. The application avoids the problems that an irradiation source is difficult to accurately control energy in a ground test process, improves the accuracy of simulation, and reduces errors.

Description

Technical Field

[0001] This invention relates to the field of simulation technology for electronic devices, and more specifically, to a simulation method for the synergistic effect of ionization / displacement in the oxide layer of a bipolar transistor. Background Technology

[0002] Due to the presence of various high-energy charged particles in space, spacecraft in orbit are inevitably affected, with electronic devices being particularly impacted during service. High-energy charged particles in space include electrons, protons, and heavy ions. Damage to electronic devices mainly includes ionizing radiation effects, displacement radiation effects, and synergistic effects of ionization and displacement. In the harsh space environment, different charged particles cause different performance damages to electronic devices. These damages range from minor device performance degradation to severe spacecraft failure. Therefore, research into the mechanisms of radiation damage to electronic devices is crucial.

[0003] Bipolar transistors and circuits have been widely used in space environments and spacecraft due to their unique performance characteristics and excellent performance. However, bipolar transistors and circuits are sensitive to both ionization and displacement effects. As research on failure analysis of electronic devices in space environments continues to advance, researchers have gradually realized that analyzing displacement and ionization effects through single proton or electron irradiation cannot meet the operational requirements of electronic devices in actual space environments. This is because most ions in the space environment (such as protons and electrons) can produce both ionization radiation and displacement radiation effects.

[0004] The ionizing radiation effect of bipolar transistors (BPTs) typically refers to the generation of oxide charges in the SiO2 oxide layer due to the incidence of charged particles, resulting in interface state traps at the Si / SiO2 interface. The displacement radiation effect of BPTs primarily refers to the creation of vacancies and interstitial atoms in silicon after the incidence of charged particles. Current research on the synergistic effect of BPTs mostly considers the interaction between the ionization effect in the oxide layer and the displacement effect in silicon, neglecting the fact that charged particle incidence also causes displacement damage in the oxide layer. Therefore, the interaction between displacement damage and ionization damage in the oxide layer is unavoidable. To study the interaction between displacement damage and ionization damage in the oxide layer, ground-based experiments and computer simulations can be used. Ground-based experiments can use multiple irradiation sources for sequential irradiation to study the synergistic effect. However, to study the synergistic effect between displacement defects and ionization defects in the oxide layer, it is essential to avoid inducing displacement defects in the silicon mass during sequential irradiation. Therefore, precise control of the irradiation source energy is necessary to ensure that the generated displacement defects are confined to the oxide layer. However, because the irradiation process is affected by a variety of factors, it is difficult to precisely control the energy of the irradiation source, which often leads to large errors when using ground-based experimental methods for research. Summary of the Invention

[0005] The problem solved by this invention is that there are large errors in ground-based experimental studies on the mechanism of the ionization / displacement synergistic effect in oxide layers on bipolar transistors.

[0006] To address the above problems, this invention provides a simulation method for the ionization / displacement synergistic effect in the oxide layer of a bipolar transistor, comprising the following steps:

[0007] Step S1: Construct an oxide layer model of a bipolar transistor. After the oxide layer model of the bipolar transistor interacts with high-energy photons to produce an ionizing radiation effect, an ionizing radiation effect defect model is obtained. The ionizing radiation effect defect model includes a first defect parameter.

[0008] Step S2: The charged particles interact with the oxide layer model of the bipolar transistor to produce a displacement radiation effect, thereby obtaining a displacement radiation effect defect model. The second defect parameter of the displacement radiation effect defect model is calculated using SRIM software.

[0009] Step S3: After associating the first defect parameter with the second defect parameter, input the data into the ionizing radiation effect defect model to obtain the ionization / displacement synergistic effect defect model, and obtain the third defect parameter of the ionization / displacement synergistic effect defect model; statistically analyze the first defect parameter, the second defect parameter, and the third defect parameter.

[0010] Further, in step S1, the construction of the oxide layer model of the bipolar transistor, after the oxide layer model of the bipolar transistor interacts with high-energy photons to undergo ionizing radiation effects, yields an ionizing radiation effect defect model, including:

[0011] The oxide layer model of the bipolar transistor was constructed using TCAD software. The simulation showed that after irradiation, the oxide layer interacted with the high-energy photons to generate electron-hole pairs. The electrons and holes moved under the influence of the internal electric field of the oxide layer and reacted with hydrogen molecules and defects in the oxide layer to release protons. The protons reacted with the hydrogen passivated dangling bonds to generate interface state traps. The holes reacted with the defects in the oxide layer to generate oxide trap charges, thus obtaining the defect model of the ionizing radiation effect.

[0012] Furthermore, a computational model is constructed based on the irradiation dose rate and the process of the reaction between the electrons and holes in the oxide layer to obtain the first defect parameters of the ionizing radiation effect defect model.

[0013] Furthermore, the first defect parameter includes defect type and defect concentration, and the defect type includes at least interface state trap, intrinsic oxygen vacancy defect, intrinsic shallow level hydrogen-oxygen vacancy defect, intrinsic deep level hydrogen-oxygen vacancy defect, charged shallow level defect and charged deep level defect.

[0014] Further, in step S2, the interaction between charged particles and the bipolar transistor oxide model to generate a displacement radiation effect yields a displacement radiation effect defect model. The second defect parameter of the displacement radiation effect defect model is calculated using SRIM software, including:

[0015] The charged particles are emitted into the oxide layer to obtain the displacement radiation effect defect model; the flux of the charged particles is the same as the actual experimental flux, and the second defect parameter of the displacement radiation effect defect model is calculated by SRIM software.

[0016] Furthermore, the charged particles include oxygen ions, and the second defect parameter includes the oxygen vacancy defect concentration.

[0017] Further, in step S3, after associating the first defect parameter with the second defect parameter and inputting it into the ionizing radiation effect defect model to obtain the ionization / displacement synergistic effect defect model, the third defect parameter of the ionization / displacement synergistic effect defect model is obtained, including:

[0018] The sum of the inherent oxygen vacancy defect concentration and the oxygen vacancy defect concentration is used as the final oxygen vacancy defect concentration and input into the ionizing radiation effect defect model to obtain the ionization / displacement synergistic effect defect model, and the third defect parameter of the ionization / displacement synergistic effect defect model is obtained.

[0019] Furthermore, the third defect parameter includes the interface state trap concentration.

[0020] Furthermore, in step S1, the high-energy photons include gamma rays.

[0021] Furthermore, in step S1, the bipolar transistor refers to an LPNP type bipolar transistor.

[0022] The simulation method for the ionization / displacement synergistic effect in the oxide layer of a bipolar transistor (BPT) described in this invention has the advantage over existing technologies in that it obtains a displacement radiation effect defect model by having charged particles interact with the BPT oxide layer model to generate a displacement radiation effect. Then, the second defect parameter of the displacement radiation effect defect model is calculated using SRIM software. This second defect parameter is correlated with the inherent parameters in the constructed BPT oxide layer model and used as input to the process of the BPT oxide layer model interacting with high-energy photons to generate an ionization radiation effect. In other words, the second defect parameter corresponding to the displacement radiation effect is combined with the inherent defects in the constructed BPT oxide layer model as the initial setting parameters for the ionization radiation process, thus simulating the direct synergistic effect between displacement radiation and ionization radiation. The first, second, and third defect parameters are statistically analyzed to verify the ionization / displacement direct synergistic effect defect model. This avoids the problems of the irradiation process being affected by various factors and the difficulty in accurately controlling the energy of the irradiation source during ground-based experiments, thus improving the accuracy of the simulation and reducing errors compared to ground-based experimental research methods. Attached Figure Description

[0023] Figure 1 This is a flowchart of the simulation method for the ionization / displacement synergistic effect in the oxide layer of a bipolar transistor in an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram showing the change in the number of oxygen vacancies in an LPNP bipolar transistor with incident depth caused by 400keV O ion incident using SRIM calculations in an embodiment of the present invention.

[0025] Figure 3 This is a statistical diagram illustrating the interface state traps generated by an LPNP bipolar transistor under irradiation at a dose rate of 100 rad / s under simulation conditions, as described in an embodiment of the present invention.

[0026] Figure 4 This is a statistical diagram illustrating the interface state traps generated by an LPNP bipolar transistor under experimental conditions at a dose rate of 100 rad / s, as described in an embodiment of the present invention. Detailed Implementation

[0027] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0028] It should be noted that, in the description of the embodiments of this application, the term "some specific embodiments" means that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same implementation or instance. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0029] This invention provides a simulation method for the ionization / displacement synergistic effect in the oxide layer of a bipolar transistor, comprising the following steps:

[0030] Step S1: Construct an oxide layer model of a bipolar transistor. After the oxide layer model of the bipolar transistor interacts with high-energy photons to produce an ionizing radiation effect, an ionizing radiation effect defect model is obtained. The ionizing radiation effect defect model includes the first defect parameter.

[0031] Step S2: The charged particles interact with the oxide layer model of the bipolar transistor to produce a displacement radiation effect, resulting in a displacement radiation effect defect model. The second defect parameter of the displacement radiation effect defect model is calculated using SRIM software.

[0032] Step S3: After associating the first defect parameter with the second defect parameter and inputting them into the ionizing radiation effect defect model, the ionization / displacement synergistic effect defect model is obtained, and the third defect parameter of the ionization / displacement synergistic effect defect model is obtained; the first defect parameter, the second defect parameter and the third defect parameter are statistically analyzed.

[0033] The simulation method for the ionization / displacement synergistic effect in the oxide layer of a bipolar transistor (BPT) described in this invention obtains a displacement radiation effect defect model by having charged particles interact with the BPT oxide layer model to generate a displacement radiation effect. Then, the second defect parameter of the displacement radiation effect defect model is calculated using SRIM software. This second defect parameter is correlated with inherent parameters in the constructed BPT oxide layer model and used as input to the process of the BPT oxide layer model interacting with high-energy photons to generate an ionization radiation effect. In other words, the second defect parameter corresponding to the displacement radiation effect is combined with the inherent defects in the constructed BPT oxide layer model as the initial setting parameters for the ionization radiation process, thus simulating the direct synergistic effect between displacement radiation and ionization radiation. The first, second, and third defect parameters are statistically analyzed to verify the ionization / displacement direct synergistic effect defect model. This avoids the problems of the irradiation process being affected by various factors and the difficulty in accurately controlling the energy of the irradiation source during ground-based experiments, improving the accuracy of the simulation and reducing errors compared to ground-based experimental research methods.

[0034] In step S1 of this embodiment, the constructed bipolar transistor oxide layer model includes a metal gate and a silicon substrate in addition to the oxide layer. Therefore, after interacting with high-energy photons, the metal gate, oxide layer, and silicon substrate work together to produce an ionizing radiation effect, resulting in an ionizing radiation effect defect model. The bipolar transistor oxide layer model constructed in this embodiment simulates the oxide layer of an actual bipolar transistor exhibiting an ionizing radiation effect, and therefore possesses inherent defects of the oxide layer material itself, including inherent oxygen vacancy defects, inherent shallow-level hydrogen-oxygen vacancy defects, and inherent deep-level hydrogen-oxygen vacancy defects.

[0035] In step S2 of this embodiment, the SRIM (Stopping and Range of Ions in Matter) software is used to calculate the stopping power and the incident range of ions in the material. The charged particles include electrons, protons, and heavy ions. The total damage cascade module in the SRIM software can calculate in detail the relationship between vacancy generation and depth after ion collision.

[0036] Step S3 in this embodiment involves associating the processes of the above two steps, linking the second defect parameter in the displacement radiation effect defect model with the first defect parameter related to the ionization radiation effect defect model, thereby constructing the ionization / displacement synergistic effect defect model. The first defect parameter includes inherent defects in the initial state of the ionization radiation effect defect model, i.e., in the bipolar transistor oxide layer model.

[0037] In some specific embodiments, in step S1, an oxide layer model of the bipolar transistor is constructed. After the oxide layer model of the bipolar transistor interacts with high-energy photons to produce an ionizing radiation effect, an ionizing radiation effect defect model is obtained, including:

[0038] An oxide model of a bipolar transistor was constructed using TCAD software. The simulation showed that after irradiation, the oxide layer interacts with high-energy photons to generate electron-hole pairs. Electrons and holes move under the influence of the internal electric field of the oxide layer and react with hydrogen molecules and defects in the oxide layer to release protons. The protons react with hydrogen passivated dangling bonds to generate interface state traps. Holes react with defects in the oxide layer to generate oxide trap charges, thus obtaining a defect model of ionizing radiation effect.

[0039] In this embodiment, an oxide layer model of a bipolar transistor is constructed using TCAD software. After irradiation, high-energy photons interact with the oxide layer, resulting in Compton scattering and generating electron-hole pairs (EHPs). Electrons and holes are transported to the metal gate and the interface between the oxide layer and the silicon substrate, respectively, under the influence of the electric field within the oxide layer. During transport, electrons, holes, and hydrogen molecules react with inherent defects in the oxide layer, releasing protons through hydrogen molecule decomposition or direct decomposition. Protons are transported to the interface between the oxide layer and the silicon substrate under the influence of the electric field, reacting with hydrogen-passivated dangling bonds to generate interface trap charges (also called interface state traps). Within the oxide layer, deep-level defects trap holes, forming very stable positively charged defects, called oxide trap charges. The transport and reactions within the oxide layer generate oxide trap charges (N... ot ) and interface trap charge (N it This is the root cause of the degradation of the electrical performance of semiconductor devices. ot The most significant impact on the electrical performance of the device is the drift in the threshold voltage. it The most important impact of the accumulation of ions on the electrical performance of the device is that it changes the surface potential of the bipolar device, leading to an increase in surface recombination, which in turn causes an excessive increase in base current, ultimately resulting in the degradation of the current gain of the bipolar device.

[0040] The reaction equations involved in the above process include:

[0041] WO δ +h + →F' δ ,

[0042] VO γ +h + →E' γ ,

[0043] E' δ +H2→E δ (H)+H + ,

[0044] E' γ +H2→E γ (H)+H + ,

[0045] E δ (H)+h + →E' δ (H),

[0046] E γ (H)+h + →E' γ (H),

[0047] Eδ (H2)+h + →E' δ (H2),

[0048] E γ (H2)+h + →E' γ (H2),

[0049] E' δ (H)2)→E' δ (H)+H + ,

[0050] E' γ (H2)→E' γ (H)+H + ,

[0051] H + +Si≡Si-H→Si≡Si + +H2;

[0052] Among them, VO δ and VO γ E is an inherent oxygen vacancy defect in the oxide layer. δ (H) and E δ (H2) represents the inherent shallow-level hydrogen-oxygen vacancy defects in the oxide layer, E γ (H) and E γ (H2) represents the inherent deep-level hydrogen-oxygen vacancy defect in the oxide layer, E' δ 、E' δ (H) and E' δ (H2) represents a charged shallow-level defect, E' γ 、E' γ (H) and E γ (H2) represents a charged deep-level defect, H + For protons, all charged defects are oxide trap charges N. ot , Si≡Si + Interface state trap N it .

[0053] In some specific embodiments, a computational model is constructed based on the irradiation dose rate and the process of electrons and holes reacting in the oxide layer to obtain the first defect parameters of the ionizing radiation effect defect model.

[0054] This embodiment, building upon the previous one, constructs a computational model based on the Compton scattering effect resulting from the interaction of high-energy photons with the oxide layer, and the relationship between the irradiation dose rate and the generated electron-hole pairs. Then, based on the electron and hole densities and the relevant reaction equations, the corresponding third defect parameters are obtained. This allows for the simulation of the defect generation process caused by ionizing radiation effects, while simultaneously acquiring the model's parameters, including the third defect parameters, thus providing a deeper understanding of the structure of the ionizing radiation effect defect model.

[0055] In some specific embodiments, the first defect parameter includes defect type and defect concentration. The defect type includes at least interface state traps, intrinsic oxygen vacancy defects, intrinsic shallow-level hydrogen-oxygen vacancy defects, intrinsic deep-level hydrogen-oxygen vacancy defects, charged shallow-level defects, and charged deep-level defects. Thus, by obtaining the corresponding defect concentration according to different defect types, detailed control over various defects in the simulation model can be achieved.

[0056] In some specific embodiments, in step S2, the charged particles interact with the bipolar transistor oxide model to generate a displacement radiation effect, resulting in a displacement radiation effect defect model. The second defect parameters of the displacement radiation effect defect model are then calculated using SRIM software, including:

[0057] Charged particles are emitted into the oxide layer to obtain a displacement radiation effect defect model. The flux of charged particles is the same as that in the actual experiment. The second defect parameter of the displacement radiation effect defect model is then calculated using SRIM software.

[0058] In this embodiment, since the vacancy defect concentration calculated by the SRIM software is generated by an incident charged particle, the SRIM result needs to be multiplied by the corresponding fluence quantity used in the experiment to obtain the actual total concentration for simulation and comparison. This results in good simulation performance and small errors.

[0059] In some specific embodiments, the charged particles include oxygen ions, and the second defect parameter includes the oxygen vacancy defect concentration.

[0060] This embodiment takes oxygen vacancy defects as an example. Here, we only consider the oxygen vacancy defect concentration at the Bragg peak. 90% of the oxygen vacancy defects in the oxide layer are VO. δ Type, after capturing a hole, will form a shallow-level charged defect, 10% of oxygen vacancy defects are VO γ The trapped hole forms a deep-level charged defect. The defect formed is a second defect parameter generated by the displacement radiation effect. Therefore, the oxygen vacancy defect generated by the incident charged particle is added to the intrinsic oxygen vacancy defect concentration at the corresponding depth in step S1 to obtain the final oxygen vacancy defect concentration.

[0061] In some specific embodiments, in step S3, after associating the first defect parameter with the second defect parameter and inputting them into the ionizing radiation effect defect model, an ionization / displacement synergistic effect defect model is obtained. The third defect parameter of the ionization / displacement synergistic effect defect model is then acquired, including:

[0062] The sum of the inherent oxygen vacancy defect concentration and the oxygen vacancy defect concentration is used as the final oxygen vacancy defect concentration and input into the ionizing radiation effect defect model to obtain the ionization / displacement synergistic effect defect model, and the third defect parameter of the ionization / displacement synergistic effect defect model is obtained.

[0063] In this embodiment, the inherent oxygen vacancy defect is simulated as the initial inherent oxygen vacancy defect of the oxide layer of the bipolar transistor in the actual experiment. The oxygen vacancy defect concentration is the oxygen vacancy defect concentration in the second defect parameter of the displacement radiation effect defect model. The sum of the above two and the final oxygen vacancy defect concentration are used as the initial setting parameter for the ionizing radiation process to simulate the ionizing radiation effect. This realizes the simulation of the direct synergistic effect between displacement radiation and ionizing radiation, and obtains the oxygen vacancy defect concentration under the ionization / displacement synergistic effect. The simulation effect is good and the error is small.

[0064] In some specific embodiments, the third defect parameter includes the interface state trap concentration. This leads to the acquisition of defect data for the ionization / displacement synergistic effect defect model.

[0065] In some specific embodiments, in step S1, the high-energy photons include gamma rays.

[0066] In some specific embodiments, in step S1, the bipolar transistor refers to an LPNP type bipolar transistor.

[0067] Example

[0068] This embodiment focuses on the simulation study of the ionization / displacement synergistic effect in the oxide layer of a lateral LPNP bipolar transistor, as detailed below:

[0069] This embodiment simulates an actual ground test, using the displacement effect of 400keV O ions in the oxide layer of a bipolar transistor and subsequent... 60 The synergistic effect of ionization caused by Co-γ-ray irradiation was investigated. First, the ionization radiation effect caused by the interaction between the bipolar transistor oxide layer and high-energy photons was constructed using TCAD software, resulting in an ionization radiation effect defect model. Then, considering the displacement effect of 400 keV O ions in the bipolar transistor oxide layer, the oxygen vacancy displacement defect distribution generated by 400 keV O ions in the oxide layer was calculated using SRIM software. It should be noted that the SRIM results need to be multiplied by the corresponding fluence used in the experiment, 1e14 / cm. 2This yields the actual total oxygen vacancy concentration. For example... Figure 2 As shown, this only considers the oxygen vacancy defect concentration at the Bragg peak, and the average value can be obtained at 1e14 / cm. 2 At the injection rate, the oxygen vacancy concentration produced was 5e19 vacancy / cm³. 3 Research indicates that 90% of the oxygen vacancy defects in the oxide layer are VO. δ Type, after capturing a hole, will form a shallow-level charged defect, 10% of oxygen vacancy defects are VO γ This type of particle trapping creates deep-level charged defects. Therefore, the oxygen vacancy defects (5e19 per cm⁻¹) generated by particle incidence... 3 ), divided into VO according to proportion δ1 = 4.5e19 pieces / cm 3 VO γ1 =5e18 pieces / cm 3 (Subscript 1 distinguishes the vacancy defects generated by particle incidence from the inherent oxygen vacancy defects in step S1), and adds it to the inherent oxygen vacancy defect concentration at the corresponding depth in step one to obtain the final oxygen vacancy defect concentration. Finally, the displacement defect concentration generated by 400 keV O ions is added to the ionizing radiation effect defect model constructed in TCAD, which is based on the interaction between the bipolar transistor oxide layer and high-energy photons. That is, the final oxygen vacancy defect concentration is used as the initial defect concentration for simulation to obtain the corresponding defect information. This is then compared with the model without the displacement defect concentration generated by 400 keV O ions, where only the displacement defect concentration generated by 400 keV O ions is added. 60 The defect information obtained after Co-γ ray irradiation was compared.

[0070] like Figure 3 The figure shows the interface state trap variation curves of a simulated LPNP bipolar transistor under a dose rate of 100 rad / s. It can be seen that at 400 keV, O ions and... 60 Simulation results for the number of interface state traps generated under co-irradiation with Co and γ rays are significantly smaller than those generated under irradiation alone. 60 The number of interface state traps generated during Co γ-ray irradiation indicates the presence of oxygen ions at 400 keV. 60 The process of interfacial state trapping generated by Co-γ rays is suppressed. Figure 4 The actual experimental results under the same conditions shown show that the obtained patterns are the same as the simulation results, which further demonstrates that the method of this invention can successfully simulate 400keV oxygen ion pairs. 60 The process of suppressing interface state trapping generated by Coγ rays was successfully simulated, that is, the synergistic effect between displacement defects and ionization defects in the oxide layer was successfully simulated.

[0071] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A simulation method for the synergistic effect of ionization / displacement in the oxide layer of a bipolar transistor, characterized in that, Includes the following steps: Step S1: Construct an oxide layer model of a bipolar transistor. After the oxide layer model of the bipolar transistor interacts with high-energy photons to produce an ionizing radiation effect, an ionizing radiation effect defect model is obtained. The ionizing radiation effect defect model includes a first defect parameter, including: An oxide layer model of the bipolar transistor was constructed to simulate the interaction between the oxide layer and the high-energy photons after irradiation, generating electron-hole pairs. The electrons and holes move under the influence of the internal electric field of the oxide layer and react with hydrogen molecules and defects in the oxide layer to release protons. The protons react with hydrogen passivated dangling bonds to generate interface state traps. The holes react with defects in the oxide layer to generate oxide trap charges, thus obtaining the defect model of the ionizing radiation effect. Step S2: The charged particles interact with the oxide layer model of the bipolar transistor to produce a displacement radiation effect, resulting in a displacement radiation effect defect model. The second defect parameters of the displacement radiation effect defect model are calculated using SRIM software, including: The charged particles are emitted into the oxide layer to obtain the displacement radiation effect defect model; the flux of the charged particles is the same as the actual experimental flux, and the second defect parameter of the displacement radiation effect defect model is calculated by SRIM software. Step S3: After associating the first defect parameter with the second defect parameter and inputting them into the ionizing radiation effect defect model, an ionization / displacement synergistic effect defect model is obtained, and the third defect parameter of the ionization / displacement synergistic effect defect model is acquired; the first defect parameter, the second defect parameter, and the third defect parameter are statistically analyzed, including: The sum of the inherent oxygen vacancy defect concentration and the oxygen vacancy defect concentration is used as the final oxygen vacancy defect concentration and input into the ionizing radiation effect defect model to obtain the ionization / displacement synergistic effect defect model, and the third defect parameter of the ionization / displacement synergistic effect defect model is obtained.

2. The simulation method for the ionization / displacement synergistic effect in the oxide layer of a bipolar transistor according to claim 1, characterized in that, In step S1, the oxide layer model for constructing the bipolar transistor includes: The oxide layer model of the bipolar transistor was constructed using TCAD software.

3. The simulation method for the ionization / displacement synergistic effect in the oxide layer of a bipolar transistor according to claim 1, characterized in that, A computational model is constructed based on the dose rate of the irradiation and the process of the reaction between the electrons and holes in the oxide layer to obtain the first defect parameter of the ionizing radiation effect defect model.

4. The simulation method for the ionization / displacement synergistic effect in the oxide layer of a bipolar transistor according to claim 3, characterized in that, The first defect parameter includes defect type and defect concentration. The defect type includes at least interface state trap, intrinsic oxygen vacancy defect, intrinsic shallow level hydrogen-oxygen vacancy defect, intrinsic deep level hydrogen-oxygen vacancy defect, charged shallow level defect, and charged deep level defect.

5. The simulation method for the ionization / displacement synergistic effect in the oxide layer of a bipolar transistor according to claim 1, characterized in that, The charged particles include oxygen ions, and the second defect parameter includes the oxygen vacancy defect concentration.

6. The simulation method for the ionization / displacement synergistic effect in the oxide layer of a bipolar transistor according to claim 1, characterized in that, The third defect parameter includes the interface state trap concentration.

7. The simulation method for the ionization / displacement synergistic effect in the oxide layer of a bipolar transistor according to claim 1, characterized in that, In step S1, the high-energy photons include gamma rays.

8. The simulation method for the ionization / displacement synergistic effect in the oxide layer of a bipolar transistor according to claim 1, characterized in that, In step S1, the bipolar transistor refers to an LPNP type bipolar transistor.

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