| In the first part of the work, a molecular dynamics simulation methodology using empirical interatomic potentials is developed to study argon ion bombardment of silicon. Sputtering, structure and stress evolution are studied at 500eV and 700eV beam energies. The ion beam energies considered in this work are similar to those used in both nanometer-scale surface patterning experiments and a particular microelectromechanical systems (MEMS) fabrication technique.; Multiple simulations of more than 100 ion impacts are conducted for both 500eV and 700eV ion energies and averaged to converge statistical descriptions of structural evolution and sputtering. Ion bombardment damages a layer near the target's surface. Sputter yields in our simulations reach nearly steady rates of 0.59 and 0.67 sputtered silicon atoms per incident argon atom for the 500eV and 700eV cases, respectively after a fluence of 2.0x10 14 ions/cm2. The evolution of stress in silicon, induced by argon ion bombardment up to fluences of 4.5x1014 ions/cm 2, is studied using an interatomic force balance method. The evolution of a compressive stress is found to be directly proportional to the number of implanted argons.; In the second part of the work, a new multiscale computational method to study surface evolution is developed. In the new method, called crater function method, an average response of the silicon surface to a single argon impact is computed using molecular dynamics simulations at 500eV beam energies. These average responses (called crater functions) show the presence of ion-stimulated mass rearrangement at the surface in addition to mass removal by sputtering. These crater functions are incorporated into a continuum transport model to study the long-time surface evolution of micrometer-sized targets. These explain experimentally observed surface evolution and long-time amplitude saturation better than existing theoretical models. |
