EPITAXIAL-GROWTH MECHANISM AT SB STEPS OF SI(001) SURFACES BY PHOTOINDUCED SI(1D) ATOMS

Elementary processes of the S(B) step growth on Si(001) surfaces with photo-induced Si atoms in the 1D state were elucidated in terms of the step structure and the potential energy change following the step growth. It was found that there are two types of the S(B) step on Si(001) surfaces; one has reactive orbitals whose spatial distributions are very similar to sigma-type dangling bonds localized at the step edge and the other has completely different dimer structures with pi-type bonds. The latter structure is more stable than the former on Si(001) surfaces. It was concluded that the S(B) step growth with Si(1D) atoms on Si(001) surfaces takes place by dimer formation at the two types of the S(B) step edges which appear alternately.