Comparative study of the atomic hydrogen interaction with Si(110)“4 × 6”-Al and Si(111)√3 × √3-Al surfaces

The effect of room temperature atomic hydrogen exposure and subsequent thermal annealing of the Si(110)"4 x 6"-Al surface has been investigated by using low energy electron diffraction (LEED) and Auger electron spectroscopy (AES). The behaviour of the Si(110)"4 x 6"-Al and Si(111)root 3 x root 3-Al surfaces were compared. It was found that on the Si(110) surface H atoms cause the agglomeration of the uniform aluminium layer into very small Al islands as on the Si(111) surface. In both cases the atomic hydrogen interaction induced the structural transformation of the original structure into the 1 x 1. The subsequent thermal annealing of both Si(111)1 x 1-H(Al) and Si(110)1 x 1-H(Al) surfaces leads to the restoring of the initial surface structures. Analysis of the isochronal annealing curves has shown a one-stage reappearing process of the root 3 x root 3 structure and a two-stage one of the "4 x 6". This difference has been ascribed to the anisotropy of the surface diffusion of Al atoms on the Si(110) surface.