Surface modification using Binary Collision Approximation and 3D Lattice Kinetic Monte Carlo simulation

Periodic pattern formation during low energetic ion-beam bombardment has been observed for many different surfaces. Two different kinds of approaches have been used to explain and simulate the pattern formation and evolution in time: (i) continuum theories, which are based on the Bradley and Harper model, and (ii) Kinetic Monte Carlo method (KMC) for surface diffusion coupled with Sigmund’s theory to incorporate sputtering. Both of them have been developed in terms of surface processes induced by ion sputtering, although without including microscopic effects, i.e. defect creation and diffusion of vacancies in the bulk.
We present a new approach using Binary Collision Approximation for simulating collision cascades during ion bombardment coupled with 3D Lattice KMC Ising model, to simulate surface and bulk diffusion of defects and vacancies. The combination of these two models gives an advantage on the simple Gaussian approximation of the deposited energy proposed by Sigmund, because it includes detailed collision cascades into the discrete lattice system. In addition, information about the relation between atomistic features, i.e. vacancies and defects creation and annihilation, sputtering yield distribution, bulk and surface diffusion, and pattern formation is obtained. We will present the time evolution of surface morphology for different initial system parameters and compare it with continuum theories. Moreover, the influence of substrate temperature on the pattern evolution is studied.