DIFFUSION AND CHANNELING OF LOW-ENERGY IONS - THE MECHANISM OF ION DAMAGE

A simple model, including both channeling and diffusion effects, has b een developed for the understanding of the mechanism of low-energy ion -induced damage. This model provided much better agreement with our ex perimental data, and yields a value for the effective diffusivity of d efects during ion bombardment as similar to 3x10(-15) cm(2)/s. The num erical results experimental data that diffusion of defects, even at ro om temperature, plays an important role in determining the profile of ion-induced damage and suggests that some enhancement of defect diffus ion occurs during ion bombardment. In addition, since the majority of defects are located in the near-surface region (within similar to 50 A ngstrom of the surface), even modest etch removal of the surface can d ramatically alter the damage profile. Therefore, surface removal has a lso been considered in our model to find the influence of etch rate on the ion damage profile. (C) 1995 American Vacuum Society.