双磨粒抛光单晶Si的分子动力学模拟

目的 通过分子动力学(MD)模拟,获得双金刚石磨粒抛光单晶Si的去除机理.方法 采用一种新的单晶硅三体磨粒抛光方法,测试双磨粒的抛光深度和横向/纵向间距对三体磨粒抛光的影响,从而获得相变、表面/亚表面损伤等情况,并获得抛光过程中温度及势能的变化情况.结果 对比抛光深度为1、3 nm时配位数的情况,发现抛光深度为1 nm...

Molecular Dynamics Simulation of Double Abrasive Polished Single Crystal Si

Molecular dynamics (MD) simulation was used to obtain the removal mechanism of double diamond abrasive polished single-crystal Si. In this study, a new three-body abrasive polishing method for monocrystalline silicon was used to test the effects of polishing depth and lateral/ longitudinal spacing of double abrasive grains on the three-body abrasive polishing process, so as to obtain insights on phase transformation, surface/subsurface damage, surface morphology, material removal and temperature and potential energy in the polishing process. Through comparison of coordination numbers when the polishing depth is 1 nm and 3 nm respectively, it is found that the atomic number of phase transition is 4319 at the end of polishing when the polishing depth is 1 nm, but 12 516 when the polishing depth is 3 nm. The number of phase change atoms and damage atoms increases when the polishing depth of abrasive particles on the surface of Si workpiece increases. The simulation results also show that the type and number of phase transition atoms in single crystal Si increase with the increase of lateral spacing, but decrease with the increase of longitudinal spacing. The initial temperature of the system is set at 298 K. When the polishing depth is 1 nm, the polishing temperature is 456 K at the end, and when the polishing depth is 3 nm, the temperature is 733 K at the end. At the end of polishing, the temperature difference between the longitudinal group and the lateral group is only 30~40 K. Among the three control groups (polishing depth, lateral and longitudinal spacing), the polishing depth has the greatest influence on the subsurface damage. When the polishing depth is 3 nm, the subsurface damage depth is the largest, which leads to more material removal from the surface of single crystal Si workpiece. This study shows that the polishing depth and spacing of double abrasive particles not only affect the surface microstructure of silicon, but also affect the phase transformation. When the simulation parameters are the same, larger polishing depth and lateral spacing will produce more phase transition atoms, because the phase transition is most affected by polishing depth and least affected by longitudinal spacing.