Sn thin film growth on Si(1 1 1) surface studied by CAICISS

Using coaxial impact–collision ion scattering spectroscopy, we have investigated Sn thin film growth on Si(1 1 1)7×7 and Si(1 1 1)√3×√3–Sn surfaces at room temperature. Sn grows epitaxially with body-centered-tetragonal structure (β-Sn) both on Si(1 1 1)7×7 surface and √3×√3-Sn surface. However, these epitaxial Sn layers exhibit markedly different growth orientations; the Sn layers on the Si(1 1 1)7×7 substrates have β-Sn(1 0 0)〈0 1 1〉//Si(1 1 1)〈0 1̄ 1〉 and β-Sn(1 0 0)〈0 1 0〉//Si(1 1 1)〈1̄ 1̄ 2〉 orientations, while those on the √3×√3-Sn surface have β-Sn(1 0 0)〈0 1 0〉// Si(1 1 1)〈0 1̄ 1〉 and β-Sn(1 0 0)〈0 1 1〉// Si(1 1 1)〈1̄ 1̄ 2〉 ones. These results reveal that the growth orientation of the epitaxial Sn layers is rotated by 30° with regard to that on a clean Si(1 1 1) surface by the presence of the √3×√3-Sn phase at the initial stage of the Sn growth.