GROWTH-KINETICS OF THERMAL SIO2 THIN-FILMS

This work presents a simple model for the thermal growth of SiO2 thin films on silicon substrates which may shed some light on the theory of silicon oxidation processes. In the model it is assumed that the time rate evolution of the oxidized region is proportional to the average number of non-oxidized silicon sites in a transition region. As a consequence, the oxide thickness x is found to scale with the oxidation time as x similar to tb in agreement with a large number of experimental data. The value of the exponent b is found to be in the range of 1/2 less than or equal to b less than or equal to 3/2 depending on the oxidation region. The model agrees with the Deal and Grove linear-parabolic law with no 'anomalous region' in the time dependence for short oxidation times. Furthermore, a supralinear regime is predicted in the early stages of the oxidation process.