Hamburg 2001 – wissenschaftliches Programm
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O: Oberflächenphysik
O 32: Epitaxie und Wachstum (II)
O 32.10: Vortrag
Donnerstag, 29. März 2001, 17:45–18:00, C
Initial Stages of Praseodymium Oxide Deposition on Si(001) — •Hans-Joachim Müssig, Jarek Dabrowski, Konstantin Ignatovich, and Victor Zavodinsky — IHP, Im Technologiepark 25, D-15236 Frankfurt (Oder), Germany
Aggressive scaling of Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) requires gate oxides with dielectric constants higher than that of SiO2. To find a suitable “High-K Material”, Pr2O3 deposition on Si(001) was studied by Scanning Tunneling Microscopy (STM) and Auger Electron Spectroscopy (AES). We present the first STM images showing the initial stages of Pr2O3 adsorption on Si(001) at 600 ∘C as a function of deposition time; these provide experimental evidence for a heteroepitaxial growth in two orthogonal directions from the beginning of deposition. Deposited molecules diffusing on the surface use dimer rows as convenient “rails”. We conclude from our experimental results that the surface protrusions caused by praseodymium oxide are ad-dimer like. Heating at 600 ∘C induces the migration of ad-dimers so that ad-dimer rows are visible. AES measurements demonstrate that in the monolayer region the thermal stability of praseodymium oxide films is lower than that of SiO2. By the time 760 ∘C is reached, the oxide is completely decomposed. While oxygen desorbs as SiO, praseodymium remains on the Si surface even with flashing at 1250 ∘C.