Molecular Dynamics Simulation Of Irradiarion Displacement Damage Of 4H-SiC Material

4H-SiC has excellent electrical characteristics such as high shift threshold,broadband gap,etc,So it has become the third-generation semiconductor material that has the most potential for the development of high-frequency and radiation-resistant devices.But in the strong radiation environment,radiation will also damage the original 4H-SiC crystal structure,and defects in the internal,these defects will make the structure of 4H-SiC crystal,the electrical properties will be changed to 4H-SiC related electronic devices using performance degradation and even failure.This article mainly considers the displacement effect in irradiation damage.The degree of deterioration of electrical properties caused by the displacement damage caused by irradiation directly determines the reliability and feasibility of using 4H-SiC materials in the field of anti-irradiation related semiconductor devices,so it is very important to fully understand the formation mechanism,microstructure,and spatial distribution of defects caused by irradiation displacement damage in the microscopic field,and to provide a theoretical basis for revealing the changes in electrical properties of electronic devices using 4H-SiC as a substrate in an irradiation environment,which may provide the basis for the use of such electronic devices for radioactive environment selection and internal structure design.This paper uses the lammps(Large-scale Atomic/Molecular Massively Parallel Simulator)simulation software,and by establishing the PKA(Primary Knock-on Atom)cascade collision model and combining the molecular dynamics method to simulate the formation and spatial distribution of 4H-SiC radiation displacement damage defects,the main work and conclusions are as follows:(1)We choose Si atoms as Primary collision(Primary if on Atom,PKA),The displacement damage of 4H-SiC material with 10 ke V energy of PKA atom incident is simulated.The results show that the generated displacement damage of radiation of the point defect types include vacancies,interstitials and antisite defects,The number of defects produced by cascaded collisions increases rapidly and then decreases and finally reaches the stationary state.(2)The effects of different PKA energy and different PKA incident directions on the formation and evolution of 4H-SiC material cascades are studied.The results show that the cascade collision vacancy quantity and the linear relationship between the PKA energy,The higher the PKA energy,the more defects will be produced;the initial PKA of the number of incident direction evolution of vacancy of 4H-SiC cascade collision with time and stable stage of survival had no obvious effect.(3)The effects of different PKA energy and different PKA incident directions on the distribution of vacancy and interstitial space.Different PKA incident energy impact collision cascade depth,and when the energy is high,there will be subcascade collision,produce multiple displacement spike,The difference in the incident angle of PKA is more affected by the distribution of the displacement peak,which leads to the irregular surface expansion of the defective clusters.(4)The influence of different energy PKA incident and different PKA incident direction on defect concentration are studied.The results show that PKA energy affects the concentration of vacancies and counter defects.The higher the energy of PKA,the greater the concentration of vacancy defects and antisite defect,the direction of initial motion of PKA has little effect on the concentration of vacancy defects,but when the incidence angle of PKA increases,it will gradual increase in the concentration of antisite defects.