Large-scale molecular dynamics simulation of sputtering process with glancing-angle Ar cluster impact on 4H-SiC

Large-scale molecular dynamics simulations with two Ar688 cluster impacts on a 4H-SiC surface are performed to investigate the mechanism of lateral sputtering caused by two clusters collisions. The two Ar clusters are composed of 688 atoms each (referred as Ar688) which are described by a simple Lennard-Jones potential. The initial velocities of both clusters are 2.55 × 104 m/s when the acceleration voltage is 100 keV. The computational volume is 30 nm × 30 nm × 16 nm, which is constructed by 1444608 4H-SiC atoms. At 0.8 ps after the impact from the first Ar cluster on the 4H-SiC surface, a second argon cluster with predetermined incident-angle collides with 4H-SiC surface at a distance of one “diameter” away from the center of the first impact where the term “diameter” refers to the diameter of the footprint of the first impact on 4H-SiC. The incident-angle of the second argon cluster was set at 0°, 60°, or 80° for three different trials. Consequently, in each case the crater formed by the first cluster showed signs of being smeared out by the impact of the second cluster. Especially at the incident-angle of 80° the effects of surface modification were clearly noticeable.