Diffusion and channeling of low-energy ions: The mechanism of ion damage

A simple model, including both channeling and diffusion effects, has been developed for the understanding of the mechanism of low-energy ion-induced damage. This model provided much better agreement with our experimental data, and yields a value for the effective diffusivity of defects during ion bombardment as ∼3x10-15 cm2/s. The numerical results support our experimental data that diffusion of defects, even at room temperature, plays an important role in determining the profile of ion-induced damage and suggests that some enhancement of defect diffusion occurs during ion bombardment. In addition, since the majority of defects are located in the near-surface region (within ∼50 A of the surface), even modest etch removal of the surface can dramatically alter the damage profile. Therefore, surface removal has also been considered in our model to find the influence of etch rate on the ion damage profile. copyright 1995 American Vacuum Society