  The thermal growth of silicon oxide films on Si in dry O2 is modelled as a
dynamical system, assuming that it is basically a diffusion-reaction
phenomenon. Relevant findings of the last decade are incorporated, as structure
and composition of the oxide/Si interface and O2 transport and reaction at
initial stages of growth. The present model departs from the well established
Deal and Grove framework (Deal, B.E. and Grove, A. S. General Relationship for
the Thermal Oxidation of Silicon, J. Appl. Phys. 36, 3770-3778 (1965))
indicating that its basic assumptions, steady-state regime and reaction between
O2 and Si at a sharp oxide/Si interface are only attained asymptotically.
Experimental growth kinetics by various authors, obtained for a wide range of
growth parameters are shown to collapse into one single curve when the scaling
properties of this model equations are explored.
