Ion Beam Bombardment Of Si And Sic Computer Simulation

In this paper, computer simulation have been used to study the interactions between low energy argon ions with silicon surface and the helium, argon, xenon ions with the SiC surface.First, a study of interactions between low energy argon ions with silicon surface using molecular dynamics (MD) simulations is reported. The mechanism of interaction have been analysed by using single Ar~+ to bombard the different position of Si atoms at the top of four layers and the interstice of atoms at the surface.The results show that the only once collision takes place when Ar~+ bombard the atoms at the top of four layers, the external energy of the ion is about 40eV and the time of interaction have about 20 to 30fs; Many times collision take place when Ar~+ impact the interstice of atoms at the surface and the max external energy is about 20eV and the energy decreasing with the increasing times of collision, the time of interaction has about 100fs, This type of impact is dominant at the process of amorphization. Moreover, we simulate the amorphization caused by 200eV argon ions impacts the surface of crystalline silicon. The results show that the depth of amorphization is the linear function with the energy of ion range from 20 to 200eV .In grazing incidence situation, a detailed analysis of the scattering trajectories is performed. The scattering process in many cases involves a sequence of simultaneous collisions between projectile and target atoms. The scattered intensity is presented as a function of the polar scattering angle, the azimuthal scattering angle and the energy loss. Various prominent features of the spectra are assigned to specific scattering trajectories.Second, The monte-carlo(MC) code SRIM have been used to simulate the sputtering yields ,distribution of sputter atoms,energy of sputter atom of SiC for bombardment by He~+,Ar~+,Xe~+ at different energies (100—500eV) and different angles (0—85degree). The calculation results show that sputtering mechanisms for light ion like He~+ is mainly caused by cascades collisions from backscatter ion under surface of SiC,and the heavy ion like Ar~+,Xe~+ is caused by cascades collisions from backscatter atom in SiC. The mean energy of sputter atoms caused by He~+ is higher than Ar~+,Xe~+ and the distribution of He~+ in SiC is rather wider than Ar~+,Xe~+. The sputter yield of SiC enhances and reachs to the max value following the incidence angle of ion gradually increasing from 0 to about 70 degree. When the incidence angle exceed 70 degree will cause the degree of the cascades collisions become too small and lead to the sputter yield decrease intensively.