Absorption characteristics of SI adatoms on the Si(100) and Si(110) surfaces

Abstract

We have employed a semiempirical molecular orbital method and a modified form of the Stillinger-Weber potential to investigate the characteristics of adsorption and diffusion of Si adatoms on the Si(110) and Si(100) surfaces. Our results for Si(110) indicate that the diffusion of the Si adatom is ani-sotropic along a low-energy zigzag path directly above the surface atomic zigzag chain. The activation energy for the Si adatom to diffuse along this zigzag path on the Si ( l 10) surface is 0.054 eV, suggesting that the Si adatom is highly mobile on Si ( l 10). For the Si(100) surface. the activation energy is about 0.33 eV with the direction of easy diffusion being parallel and to the side of the dimer rows on the fully relaxed Si (100) 2Xl surface.