Initial stage of the Bi surfactant-mediated growth of Ge on Si 111/: a structural study

We have used Bi as a surfactant in Ge growth on Si 111.and present a detailed analysis of the adsorption site geometry of Bi on bare Si 111. as well as on ultrathin Ge films 1–2 monolayers, ML. grown on Bi-terminated Si 111.. X-ray standing waves XSWs.have been employed to show that at a growth temperature of 4858C, Bi occupies T1 adsorption sites on Si 111.. After Ge deposition, a site exchange of Ge and Bi is observed, and Bi is found to reside on T1 sites on top of the pseudomorphically strained Ge. The Si`Bi and the Ge`Bi bond lengths have been determined to be very close to the sum of the respective covalent radii. q2000 Elsevier Science B.V. All rights reserved