Regensburg 2004 – wissenschaftliches Programm

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O: Oberflächenphysik

O 40: Halbleiteroberflächen und -grenzflächen

O 40.9: Vortrag

Donnerstag, 11. März 2004, 17:45–18:00, H45

Epitaxial Pr2O3 layers on Si (111) studied with LEED and surface XRD — •Nicole Jeutter, Zarife Özer, and Wolfgang Moritz — Section Crystallography, Department of Earth and Environmental Sciences, University of Munich

Pr2O3 is one of the few oxides which are stable in contact with Si at temperatures up to 1000 C. It has as high dielectric constant and a small lattice mismatch (under 0.3 %) to the Si (111) substrate lattice. We have grown Pr2O3 on the Si (111) surface by evaporation from a tungsten crucible loaded with Pr6O11. Measurements with LEED and XRD show that an epitaxial layer is formed at a substrate temperature of about 770 K with the (0001) plane of Pr2O3 parallel to the Si (111) surface. Subsequent annealing up to 1030 K for less than 2 minutes leads to a p(2x2) reconstruction of the Pr2O3 layer. Very weak reflections from a (√3x√3) structure appear after slow cooling to room temperature. A disordered (5x1) phase appears after desorption at temperatures above 1050 K. After further desorption the (7x7) structure of the Si (111) surface is recovered. First x-ray measurements show the orientation relative to the substrate. The interface consists of a Si-O-Pr bond with Pr above the T4 site. No indication was found for an intermediate oxide layer. The thickness of the layer was 0.6 nm, corresponding to one unit cell of Pr2O3.

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