Amorphous La x Al y O films, containing 100, 50, and 30% La, were deposited by atomic layer deposition ͑ALD͒ on ultrathin SiO 2 films ͑1 nm͒. Changes in the depth profile, as a function of composition, and structure were examined by medium energy ion scattering and transmission electron microscopy. The electronic structure of the La x Al y O films was investigated by X-ray photoelectron spectroscopy as a function of La concentration and postdeposition annealing temperature. In the case of a pure La 2 O 3 film without Al 2 O 3 , the SiO 2 at the interfacial layer had been converted to SiO 2−x and La silicate during the ALD process. However, in case of a La 2 O 3 film with Al 2 O 3 , interfacial reactions were significantly suppressed. In particular, silicate formation in the La 2 O 3 films gradually increased with the increasing annealing temperature, while that in La 2 O 3 films incorporated Al 2 O 3 was suppressed up to an annealing temperature of 800°C.
The atomic structure of Si(113) has been studied by using time-of-flight coaxial impact collision ion scattering spectroscopy (ToF-CAICISS) and reflection high-energy electron diffraction (RHEED). The RHEED observations showed two ordered phases of 3 × 2 and 3 × 1. A phase transition of 3 × 2 to 3 × 1 was observed to occur reversibly in a temperature range of 450-550• C. From the CAICISS measurements, it was found that the intensity variations of the 3 × 2 phase are most probably consistent with the 3 × 1 phase and they are almost symmetric on [332], suggesting a geometrical similarity in the local atomic structure between the two reconstructions. It turned out that two reconstructions have top surface atoms with arrangement along [110], probably forming a unit of five atoms having a dimer as in previously reported structural models. The interatomic distance or bond length between the top surface atoms was determined. In particular, it was found that the dimer is positioned slightly lower than the other two top surface atoms. From these results, the atomic structure of Si (113) is discussed on the basis of previously reported structural models, including the unit of five atoms and the adatoms.
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