Berlin 2005 – wissenschaftliches Programm
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O: Oberflächenphysik
O 46: Adsorption an Oberfl
ächen V
O 46.3: Vortrag
Dienstag, 8. März 2005, 16:15–16:30, TU EB420
Alternative Gate Oxide Pr2O3: Growth characterization on Si(111) and Si(113) — •N.M. Jeutter1, M. Hennemeyer1, L. Libralesso2, T.-L. Lee2, J. Zegenhagen2, A. Stierle3, and W. Moritz1 — 1Dept. of Earth- and Enviromental Sciences, LMU Munich, Germany — 2ESRF, Grenoble, France — 3MPI MF, Stuttgart, Germany
GIXRD measurements of a 0.6 nm thick Pr2O3 -layer on Si(111) show that the interface is formed by an Pr-O-Si bond with oxygen on top of Si. Evidence is found from XRD and LEED measurements that Pr2O3 grows at 500 ∘ C in double layers, corresponding to one unit cell of the hexagonal Pr2O3 bulk phase. Annealing up to 760 ∘ C of the thicker layers leads to island growth and formation of PrSi2. The p(2x1) and the coexisting p(√3 x √3) structures, occurring in the LEED pattern after annealing, are probably due to submonolayer coverage of Pr on Si (111)[1].
The growth of Pr2O3 on Si(113) has been investigated by LEED and X-ray diffraction. Pr2O3 was evaporated at a substrate temperature of 600 ∘ C. After deposition of 0.2 nm of Pr2O3, the reconstruction of the clean surface is removed and the LEED pattern exhibits a streaky (4x1) superstructure. AFM images show flat islands of triangular to trapezoid form. First GIXRD measurements did not show any superstructure reflections indicating that the (4x1)pattern seen in LEED arises from the oxygen ordering.
[1] L. Grill, M.G. Ramsey, J.A.D. Matthew, F.P. Netzer, Surface Science 380 (1997) 324-334