AVS 53rd International Symposium
    Electronic Materials and Processing Friday Sessions
       Session EM+TF-FrM

Paper EM+TF-FrM12
Oxidation Properties of Al-nanostructures on Si Surfaces

Friday, November 17, 2006, 11:40 am, Room 2003

Session: High-k Dielectric & Multi-Functional Oxide Growth & Processing
Presenter: P. Morgen, University of Southern Denmark
Authors: P. Morgen, University of Southern Denmark
C. Janfelt, University of Copenhagen, Denmark
K. Pedersen, University of Aalborg, Denmark
Z.S. Li, University of Aarhus, Denmark
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We have explored the oxidation properties of different nanostructures of Al formed by deposition of Al on Si surfaces with surface sensitive techniques to reveal the differences in reactivity between differently organized nanostructures of Al on these surfaces. In a parallel effort some of these reactions have been modeled with surface electronic structure calculations simulating STM and photoemission spectra, based on the DFT method. Recently several theorists have looked at the initial phases of oxide formed during exposure of Al to oxygen, and found these to differ from bulk Al-oxide. Here we discuss the results for the oxidation of Al on Si (111) and Si (100) in quantities of less than a monolayer as deposited and after annealing of these systems. For the un-annealed systems we discover a route to control the formation of Al-oxide on top of Si with a sharp unmixed interface, while the reactions of the annealed systems show mixing and enhanced reactivity of the Si surface to oxygen. Ultrathin films of Al on top of Si oxidize at room temperature and at elevated temperatures as a self limiting process, like Si itself. The structure of this oxide includes Al with a coordination number of four.