Multi-scale simulation method for radiation displacement damage of silicon carbide device

Abstract

The invention discloses a multi-scale simulation method for radiation displacement damage of a silicon carbide device, and the method comprises the steps: building a 4H-SiC crystal system, and carrying out the molecular dynamics simulation, thereby obtaining a change curve of the position and size of an amorphous region under different primary recoil particle energies; in combination with material displacement threshold energy, through Monte Carlo calculation software, simulating a defect distribution condition generated under high-energy particle incidence; establishing a corresponding amorphous material region in a 4H-SiC device model in finite element software according to a change curve of the position and the size of the amorphous region under different primary recoil particle energies; and then according to the defect distribution condition, establishing corresponding trap distribution in the 4H-SiC device model to obtain the degradation condition of the 4H-SiC device model under irradiation. According to the method, the irradiation degradation of the silicon carbide device under space application is analyzed, and the prediction accuracy of the irradiation degradation of the device is improved by analyzing the amorphous material.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor design, and in particular to a multi-scale simulation method for radiation displacement damage of a silicon carbide device. Background Art

[0002] With the development of aerospace technology, satellites with diverse functions have emerged, such as communications, meteorological, and remote sensing satellites. Various semiconductor devices are widely used in various spacecraft, including satellites. SiC devices, with their exceptionally high breakdown voltage and thermal stability, are suitable for satellite power management systems, power conditioners, and ultraviolet detection systems, finding widespread application. However, due to the harsh radiation environment of space, SiC devices are inevitably exposed to high-energy particles. Device failures in space are primarily caused by high-energy particle exposure in the space environment. Common types of space radiation damage can be categorized as non-ionizing and ionizing. Ionizing damage primarily occurs through ionization, generating hole-electron pairs within the device, thus affecting device performance. Non-ionizing energy loss, primarily displacement damage, is determined by the material's displacement threshold energy (Ed), the type of incident particle, and the particle energy. Displacement damage occurs when particles collide with target atoms, transferring energy to the target atoms, causing them to move from their lattice positions and forming Frenkel pairs, or vacancy-interstitial pairs. The displacement effect forms point defects in the device. These defects are partially recovered under thermal motion, and partially exist permanently in the device. They capture electrons under the action of the electric field, and eventually lead to degradation of device performance. According to statistics on past on-orbit failure rates, failures caused by the space environment account for 46% of the total failures. Accurately predicting the radiation degradation behavior of devices is of great practical significance. At present, displacement damage is mainly verified through experiments, but the experimental method is time-consuming and expensive. Therefore, it is of great significance to develop corresponding simulation methods. The current simulation method mainly uses the defects caused by displacement damage as traps to study the degradation behavior of devices. Under actual irradiation, the cascade reaction inside the device causes local high temperature. Under the joint action of atomic displacement, point-distributed amorphous materials will appear in the device. The existing methods have certain deviations in the simulation of device displacement damage. The present invention expands the simulation method of device irradiation displacement damage, takes into account the amorphization behavior caused by irradiation, and improves the accuracy of the simulation method. Summary of the Invention

[0003] The purpose of the present invention is to provide a tool for researching and analyzing the reliability of silicon carbide space radiation, and to provide a multi-scale simulation method for radiation displacement damage of silicon carbide devices.

[0004] The object of the present invention is achieved through the following technical solution: a multi-scale simulation method for radiation displacement damage of silicon carbide devices, comprising the following steps:

[0005] (1) Establish the corresponding 4H-SiC crystal system in the molecular dynamics method and perform relaxation;

[0006] (2) Setting the ensemble, simulation time step, temperature, boundary conditions, primary recoil particle position, primary recoil particle incident direction, primary recoil particle type, and primary recoil particle energy, and performing molecular dynamics simulation on the 4H-SiC crystal system to obtain the position and size curves of the amorphized region generated under different primary recoil particle incident energies;

[0007] (3) Calculate the average displacement threshold energy of 4H-SiC material by molecular dynamics simulation of 4H-SiC material;

[0008] (4) Combined with the average displacement threshold energy of 4H-SiC material, the Monte Carlo calculation software is used to simulate the defect distribution caused by high-energy particle incidence;

[0009] (5) Based on the change curves of the position and size of the amorphous region under different primary recoil particle energies, the corresponding amorphous material region is established in the 4H-SiC device model in the finite element TCAD software; then, based on the defect distribution, the corresponding trap distribution is established in the 4H-SiC device model to obtain the degradation of the 4H-SiC device model under irradiation.

[0010] Furthermore, the step (2) specifically includes the following sub-steps:

[0011] (2.1) Setting the temperature, boundary conditions, primary recoil particle position, primary recoil particle incident direction, primary recoil particle type, and primary recoil particle energy;

[0012] (2.2) The ensemble is set to NVE, and the simulation time step is set to 0.01 femtoseconds;

[0013] (2.3) Conduct molecular dynamics simulations of the temperature and amorphization behavior of the 4H-SiC crystal system at the same primary recoil particle energy, and calculate the location and size of the amorphized region of the 4H-SiC crystal system;

[0014] (2.4) Based on the primary recoil particle energy, the position and size of the amorphized region, a curve of the position and size of the amorphized region under different primary recoil particle energies is established.

[0015] Furthermore, the step (3) specifically includes the following sub-steps:

[0016] (3.1) Through molecular dynamics simulation of 4H-SiC material;

[0017] (3.2) selecting a primary recoil particle and setting an initial energy, wherein the initial energy is greater than 200 eV; then iterating in the direction of kinetic energy using a bisection method, setting the initial energy as the upper limit of the initial energy and setting 0 eV as the lower limit of the initial energy;

[0018] At the nth iteration, determine whether the primary recoil particle leaves the lattice position:

[0019] If so, set the initial energy upper limit E of the n+1th iteration max,n+1 For E max,n+1 =E PKA,n , and set the initial energy lower limit E of the n+1th iteration min,n+1 For E min,n+1 =E min,n , where E PKA,n is the energy of the primary recoil particle in the nth iteration, E min,n is the lower limit of the initial energy of the nth iteration;

[0020] If not, set the initial energy limit E for the n+1th iteration max,n+1 For E max,n+1 =E max,n , and set the initial energy lower limit E of the n+1th iteration min,n+1 For E min,n+1 =E PKA,n , where E max,n is the upper limit of the initial energy of the nth iteration;

[0021] Then the energy E of the primary recoil particle in the n+1th iteration is calculated PKA,n+1 For E PKA,n+1 =(E max,n+1 +E min,n+1 ) / 2;

[0022] Until E max,n+1 -E min,n+1 The iteration ends when it is no more than 0.5eV, and the initial energy upper limit obtained from the last round of iteration is used as the material energy upper limit E max The initial energy lower limit obtained from the last round of iteration is used as the material energy lower limit E min ;

[0023] Finally got the direction Displacement threshold energy

[0024] (3.3) Changing the kinetic energy direction of the primary recoil particles, repeating step (3.2) to obtain the displacement threshold energy in different kinetic energy directions, and then summing and averaging to obtain the average displacement threshold energy of the 4H-SiC material.

[0025] Furthermore, the step (4) specifically includes the following steps:

[0026] (4.1) In the Monte Carlo calculation software, establish the corresponding layered material distribution structure according to the actual device structure;

[0027] (4.2) According to the average displacement threshold energy of 4H-SiC material, the displacement threshold energy of each atom in the corresponding layered material distribution structure and the type, direction, and energy of the incident high-energy particle are set;

[0028] (4.3) Calculate the distribution of defects caused by irradiation within the corresponding layered material distribution structure.

[0029] Furthermore, the step (5) specifically includes the following sub-steps:

[0030] (5.1) Establish a 4H-SiC device model in the finite element TCAD software and verify whether the 4H-SiC device model is correct;

[0031] (5.2) Based on the change curves of the position and size of the amorphized region under different primary recoil particle energies, the corresponding amorphous material is established. Based on the relationship between the incident particle energy and the position and size of the amorphous region, the corresponding amorphous material region is established in the 4H-SiC device model after verification in the finite element TCAD software;

[0032] (5.3) Analyze and calculate the defect distribution, establish the corresponding trap distribution within the verified 4H-SiC device model, and calculate the trap density based on the irradiation dose;

[0033] (5.4) Obtain the degradation of the 4H-SiC device model under irradiation after verification.

[0034] The beneficial effects of the present invention are as follows: the present invention analyzes the defects formed by the displacement damage of the material caused by radiation and the degradation caused by amorphization; by considering the amorphization behavior caused by radiation and through the quantitative relationship between the incident particles and the amorphous area, the degradation of the device under space radiation is more accurately predicted, thereby providing a basis for the reliability research of SiC devices in space applications. At the same time, this method can be extended to the radiation reliability analysis of other materials and devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic diagram of a multi-scale simulation method for radiation displacement damage in silicon carbide devices;

[0036] Figure 2 This is a flow chart of a multi-scale simulation method for radiation displacement damage of silicon carbide devices;

[0037] Figure 3This is a graph showing the time evolution of the amorphous region using a multi-scale simulation method for radiation displacement damage in silicon carbide devices. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to illustrate the present invention, rather than to represent all embodiments. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0039] like Figure 1 As shown, molecular dynamics, Monte Carlo simulation, and TCAD device finite element simulation are combined to achieve multi-scale, cross-time simulation for different scales. The irradiation evolution of microscopic materials is simulated. Molecular dynamics, combined with different incident particle types and energies, is used to determine the location and size of the irradiated amorphous state and the displacement threshold energy of the material. The displacement threshold energy is used as a variable and combined with the Monte Carlo method to calculate the internal defect distribution of the irradiated silicon carbide material. Finally, non-static and defect distribution are added to the TCAD finite element simulation to obtain more accurate irradiation damage behavior, thereby enabling prediction of actual device degradation in space service environments. In one embodiment, the molecular dynamics software is Lammps, the Monte Carlo software is SRIM, and the TCAD software is Sentaurus. This method can link the effects of different particle types and energies on SiC devices from the atomic level to macroscopic electrical properties, characterize the effects of stress, thermal, and electrical coupling, track the trajectory of particles after entering the SiC device, characterize the effects of different SiC device structures, and assist in the design of displacement damage protection for SiC devices. The entire method is scalable and can be extended to devices made of other materials.

[0040] Example 1

[0041] like Figure 2 As shown, the present invention provides a multi-scale simulation method for radiation displacement damage of silicon carbide devices, comprising the following steps:

[0042] (1) The corresponding 4H-SiC crystal system was established in the molecular dynamics method and relaxation was performed.

[0043] (2) Setting the ensemble, simulation time step, temperature, boundary conditions, primary recoil particle position, primary recoil particle incident direction, primary recoil particle type and primary recoil particle energy, and performing molecular dynamics simulation on the 4H-SiC crystal system, the position and size change curves of the amorphized region generated under different primary recoil particle incident energies are obtained.

[0044] The step (2) specifically includes the following sub-steps:

[0045] (2.1) Set the temperature, boundary conditions, primary recoil particle position, primary recoil particle incident direction, primary recoil particle type, and primary recoil particle energy. The primary recoil particle is placed at the bottom of the system, with the incident direction perpendicular to the bottom and upward. The system size must ensure that the primary recoil particle eventually stops within the system.

[0046] (2.2) The ensemble is set to NVE, and the simulation time step is set to 0.01 femtoseconds.

[0047] (2.3) Molecular dynamics simulations were performed on the temperature and amorphization behavior of the 4H-SiC crystal system at the same primary recoil particle energy to calculate the position and size of the amorphization region of the 4H-SiC crystal system, as shown in Figure 2. Figure 3 shown.

[0048] (2.4) Based on the primary recoil particle energy, the position and size of the amorphized region, a curve of the position and size of the amorphized region under different primary recoil particle energies is established.

[0049] (3) The average displacement threshold energy of 4H-SiC material was calculated by molecular dynamics simulation of 4H-SiC material.

[0050] The step (3) specifically includes the following sub-steps:

[0051] (3.1) Through molecular dynamics simulation of 4H-SiC material.

[0052] (3.2) selecting a primary recoil particle and setting an initial energy, wherein the initial energy is greater than 200 eV; then iterating in the direction of kinetic energy using a bisection method, setting the initial energy as the upper limit of the initial energy and setting 0 eV as the lower limit of the initial energy;

[0053] At the nth iteration, determine whether the primary recoil particle leaves the lattice position:

[0054] If so, set the initial energy upper limit E of the n+1th iteration max,n+1 For E max,n+1 =E PKA,n , and set the initial energy lower limit E of the n+1th iteration min,n+1 For E min,n+1 =E min,n , where E PKA,n is the energy of the primary recoil particle in the nth iteration, E min,n is the lower limit of the initial energy of the nth iteration;

[0055] If not, set the initial energy limit E for the n+1th iteration max,n+1 For Emax,n+1 =E max,n , and set the initial energy lower limit E of the n+1th iteration min,n+1 For E min,n+1 =E PKA,n , where E max,n is the upper limit of the initial energy of the nth iteration;

[0056] Then the energy E of the primary recoil particle in the n+1th iteration is calculated PKA,n+1 For E PKA,n+1 =(E max,n+1 +E min,n+1 ) / 2;

[0057] Until E max,n+1 -E min,n+1 The iteration ends when it is no more than 0.5eV, and the initial energy upper limit obtained from the last round of iteration is used as the material energy upper limit E max The initial energy lower limit obtained from the last round of iteration is used as the material energy lower limit E min ;

[0058] Finally got the direction Displacement threshold energy

[0059] (3.3) Changing the kinetic energy direction of the primary recoil particles, repeating step (3.2) to obtain the displacement threshold energy in different kinetic energy directions, and then summing and averaging to obtain the average displacement threshold energy of the 4H-SiC material.

[0060] (4) The average displacement threshold energy of 4H-SiC material is combined with Monte Carlo calculation software to simulate the defect distribution caused by high-energy particle incidence.

[0061] The step (4) specifically includes the following steps:

[0062] (4.1) In the Monte Carlo calculation software, the corresponding layered material distribution structure is established according to the actual device structure.

[0063] In one embodiment, the Monte Carlo calculation software is SRIM; in another embodiment, the Monte Carlo calculation software is Geant4.

[0064] (4.2) According to the average displacement threshold energy of 4H-SiC material, the displacement threshold energy of each atom in the corresponding layered material distribution structure and the type, direction, and energy of the incident high-energy particles are set.

[0065] (4.3) Calculate the distribution of defects caused by irradiation within the corresponding layered material distribution structure.

[0066] (5) Based on the change curves of the position and size of the amorphous region under different primary recoil particle energies, the corresponding amorphous material region is established in the 4H-SiC device model in the finite element TCAD software; then, based on the defect distribution, the corresponding trap distribution is established in the 4H-SiC device model to obtain the degradation of the 4H-SiC device model under irradiation.

[0067] The step (5) specifically includes the following sub-steps:

[0068] (5.1) Establish a 4H-SiC device model in the finite element TCAD software and verify whether the 4H-SiC device model is correct.

[0069] In one embodiment, the finite element TCAD software is Sentaurus; in another embodiment, the finite element TCAD software is Silvaco or CogendaTCAD.

[0070] (5.2) Based on the change curve of the position and size of the amorphous region under different primary recoil particle energies, the corresponding amorphous material is established. Through the relationship between the incident particle energy and the position and size of the amorphous region, the corresponding amorphous material region is established in the 4H-SiC device model after verification in the finite element TCAD software.

[0071] (5.3) The defect distribution is analyzed and calculated, and the corresponding trap distribution is established in the verified correct 4H-SiC device model. The trap density is calculated based on the irradiation dose.

[0072] (5.4) Obtain the degradation of the 4H-SiC device model under irradiation after verification.

[0073] Therefore, the present invention adopts the above method to analyze the radiation degradation of silicon carbide devices in space applications, and analyzes amorphous materials to improve the accuracy of device radiation degradation prediction. The present invention simulates the radiation amorphized structure through molecular dynamics, and combined with the existing radiation degradation simulation method, it can more accurately simulate the degradation behavior of the device caused by radiation. The present invention conducts theoretical analysis by establishing the relationship between amorphous structure and radiation energy and irradiated particles, thereby forming a quantitative relationship. For the same material, the distribution of amorphous materials can be established through the corresponding quantitative relationship, and device modeling can be performed for radiation amorphization. Compared with the existing method, this method can better predict the degradation behavior of the device, and it itself has less impact on the simulation method.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A multi-scale simulation method for radiation displacement damage of silicon carbide devices, characterized in that: The following steps are involved: (1) Establishing the corresponding 4H-SiC crystal system in the molecular dynamics method and performing relaxation; (2) setting the ensemble, simulation time step, temperature, boundary conditions, primary recoil particle position, primary recoil particle incident direction, primary recoil particle type and primary recoil particle energy, and performing molecular dynamics simulation on the 4H-SiC crystal system to obtain the position and size change curves of the amorphized region generated under different primary recoil particle incident energies; (3) Calculate the average displacement threshold energy of 4H-SiC material by molecular dynamics simulation of 4H-SiC material; (4) Combined with the average displacement threshold energy of 4H-SiC material, the Monte Carlo calculation software is used to simulate the defect distribution caused by high-energy particle incidence; (5) According to the change curves of the position and size of the amorphized area under different primary recoil particle energies, the corresponding amorphous material area is established in the 4H-SiC device model in the finite element TCAD software. Then, according to the defect distribution, the corresponding trap distribution is established in the 4H-SiC device model to obtain the degradation of the 4H-SiC device model under irradiation.

2. A multi-scale simulation method for radiation displacement damage of silicon carbide devices according to claim 1, characterized in that: The step (2) specifically includes the following sub-steps: (2.1) Setting the temperature, boundary conditions, primary recoil particle position, primary recoil particle incident direction, primary recoil particle type and primary recoil particle energy; (2.2) The ensemble is set to NVE, and the simulation time step is set to 0.01 femtoseconds; (2.3) Molecular dynamics simulation of the temperature and amorphization behavior of the 4H-SiC crystal system was performed at the same primary recoil particle energy to calculate the position and size of the amorphization region of the 4H-SiC crystal system; (2.4) Based on the primary recoil particle energy, the position and size of the amorphized region, a curve of the position and size of the amorphized region under different primary recoil particle energies is established.

3. The multi-scale simulation method for radiation displacement damage of silicon carbide devices according to claim 1, characterized in that: The step (3) specifically includes the following sub-steps: (3.1) Through molecular dynamics simulation of 4H-SiC material; (3.2) selecting a primary recoil particle and setting an initial energy, wherein the initial energy is greater than 200 eV; then iterating in the kinetic energy direction using a dichotomy method, setting the initial energy as an upper limit of the initial energy, and setting 0 eV as a lower limit of the initial energy; At the nth iteration, determine whether the primary recoil particle leaves the lattice position: If so, set the initial energy upper limit E of the n+1th iteration max,n+1 For E max,n+1 =E PKA,n , and set the initial energy lower limit E of the n+1th iteration min,n+1 For E min,n+1 =E min,n , where E PKA,n is the energy of the primary recoil particle in the nth iteration, E min,n is the lower limit of the initial energy of the nth iteration; If not, set the initial energy limit E of the n+1th iteration max,n+1 For E max,n+1 =E max,n , and set the initial energy lower limit E of the n+1th iteration min,n+1 For E min,n+1 =E PKA,n , where E max,n is the upper limit of the initial energy of the nth iteration; Then the energy E of the primary recoil particle in the n+1th iteration is calculated PKA,n+1 For E PKA,n+1 =(E max,n+1 +E min,n+1 ) / 2; Until E max,n+1 -E min,n+1 The iteration ends when it is no more than 0.5 eV, and the initial energy upper limit obtained from the last round of iteration is taken as the material energy upper limit E max The initial energy lower limit obtained in the last round of iteration is taken as the material energy lower limit E min ; Finally got the direction Displacement threshold energy (3.3) Changing the kinetic energy direction of the primary recoil particle, repeating step (3.2) to obtain the displacement threshold energy in different kinetic energy directions, and then summing and averaging to obtain the average displacement threshold energy of the 4H-SiC material.

4. The multi-scale simulation method for radiation displacement damage of silicon carbide devices according to claim 1, characterized in that: The step (4) specifically comprises the following steps: (4.1) In the Monte Carlo calculation software, establish the corresponding layered material distribution structure according to the actual device structure; (4.2) According to the average displacement threshold energy of 4H-SiC material, the displacement threshold energy of each atom in the corresponding layered material distribution structure and the type, direction and energy of the incident high-energy particles are set; (4.3) Calculate the defect distribution caused by irradiation in the corresponding layered material distribution structure.

5. The multi-scale simulation method for radiation displacement damage of silicon carbide devices according to claim 1, characterized in that: The step (5) specifically includes the following sub-steps: (5.1) Establish a 4H-SiC device model in the finite element TCAD software and verify whether the 4H-SiC device model is correct; (5.2) According to the change curve of the position and size of the amorphous region under different primary recoil particle energies, the corresponding amorphous material is established, and through the relationship between the incident particle energy and the position and size of the amorphous region, the corresponding amorphous material region is established in the 4H-SiC device model after being verified to be correct in the finite element TCAD software; (5.3) Analyze and calculate the defect distribution, establish the corresponding trap distribution in the 4H-SiC device model after verification, and calculate the trap density based on the irradiation dose; (5.4) Obtain the degradation of the 4H-SiC device model under irradiation after verification.

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