6H-SiC辐照点缺陷诱发化学无序的分子动力学分析

Molecular Dynamics Analysis of Chemical Disorders Induced by Irradiated Point Defects in 6H-SiC

为配合6H-SiC中化学无序对其导电性能影响的研究,本研究运用经典分子动力学方法,采用LAMMPS软件对6H-SiC的线性级联碰撞过程进行了模拟,给出了在不同能量、不同种类PKA(Primary Knock-on Atom)的情况下,6H-SiC单次线性级联碰撞和多次线性级联碰撞过程中主要点缺陷的演化过程,并统计了多次级联碰撞后化学无序的演化和六种点缺陷各自最终所占的比例。结果表明,级联碰撞产生的Si–Si键比C–C键更易形成且更加稳定,Si–Si键主要由SiC反位缺陷形成, C–C键主要由C间隙原子聚集形成, PKA的种类及初始能量影响点缺陷的产额和化学无序的程度,但不影响六种点缺陷各自的占比。

To cooperate with studying the influence of chemical disorder on the conductivity of 6H-SiC, the linear collision cascade of 6H-SiC was simulated by the classical molecular dynamics with LAMMPS. Evolution process of main point defects in 6H-SiC during single linear cascade collision and multiple linear cascade collisions under different energy and different types of PKA(Primary Knock-on Atom) is given, while chemical disorder and the final proportion of each of the point defects are counted. The results show that the Si–Si bond generated by the linear cascade collision is easier to form and more stable than the C–C bond. The Si–Si bond is mainly formed by the antisite defect SiC, the C–C bond is mainly formed by the C-interstitial cluster. Their chemical disorder and point defect yield are affected by the type and initial energy of PKA. However, the proportion of each point defect is almost unchanged.