STUDIES OF THIN-FILM GROWTH, ADSORPTION, AND OXIDATION BY IN-SITU, REAL-TIME, AND EX-SITU ION-BEAM ANALYSIS

A time-of-flight (TOF) ion scattering and direct recoil spectrometer ( ISS/DRS) has been developed to study the surface composition and recon struction of metals, metal-oxides, and semiconductors, and to provide in situ characterization of the thin-film deposition process. The in s itu, real-time study of Pb, Zr, and Ru ultrathin films produced by ion beam sputter deposition is presented here as the first demonstration of TOF-ISS as a means of characterizing monolayer and submonolayer gro wth, both in UHV and in mTorr oxygen background. The capability of per forming surface analysis at pressures >10(-3) Torr is unique to pulsed ion beam surface analysis among surface analytical methods and enable s the in situ monitoring of oxide thin-film growth processes and surfa ce-gas phase reactions. Using angular-resolved ISS combined with Auger electron spectroscopy, we studied the oxygen adsorption and reconstru ction of (001) oriented InSb thin-film surfaces. It was found that the adsorption of molecular oxygen on the InSb (001) surface is consisten t with the Langmuir model. Oxygen adsorption preferentially occurs on the antimony sites corresponding to the extension of the lattice into the vacuum and reduces the inward contraction of the first two layers of the clean InSb (001) surface relative to the bulk atomic spacing.