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Jeutter, Nicole Martha (2003): Wachstum von Praseodymoxid auf Silizium (111) und (113). Dissertation, LMU München: Fakultät für Geowissenschaften



Alternative gateoxide Pr2O3 : Growth characterization on Si (111) and Si (113) Several investigations have been made to desricbe the interface structure of this oxide on Si(111). These studies [Tarsa et al., Müssig et al.] did show that the (001) plane of the hexagonal phase of Pr2O3 is growning on the Si(111) surface. Last year we reported about the p(1x1) observed in LEED. With gracing incidence x-ray diffraction measurements, we can now explain the bonding and positions of the Pr-Atoms and the orientation of the oxide parallel to the surface. Several evidences lead to the assumption, that the layer only occurs as a monolayer (= one unit cell of hexagonal Pr2O3 bulk phase along the c vector). Thicker layers observed in LEED, did not show any different reconstructions. In situ GIXRD measurments of thicker layers are underway. Postannealing up to 760°C of the thicker layers leads to Island growth and forming PrSi2. The therby seen p(2x2) reconstruction in LEED is formed from submonolayer coverage of Pr on Si (111). The growth on Si(113) is reported the first time. The depostion was made out of a tungsten or out of a mo-crucible at 500°C, like it was used for Si (111). After the depostion of 0.2 nm of Pr2O3 one can observe a change in the LEED pattern from the exhibited (3x1) or (3x2) reconstruction of Si (113) into a weak (4x1) pattern. AFM pictures show an ordering in on dimension and islands of triangular to trapezioid forms. The roughness is lower than the one, seen on the p(2x2) reconstructed surface. First GIXD measurements did not show any reconstructions peaks, which indicates that the pattern seen in Leed is coming from the oxygen ordering.