Oxidation of Si and TiSi2 thin films in rf oxygen plasma

We have investigated the oxidation of silicon and titanium disilicide in a rf oxygen plasma at floating potential in the 400–900 °C temperature range. Rutherford backscattering spectrometry and nuclear reaction analysis have been used to determine the kinetics of oxide growth and the elemental depth distribution in the oxide layers. For both oxides formed on Si and TiSi2 we have evidenced two different regimes in the growth, depending upon the temperature. The transition temperature between these two regimes is about 600 °C. In the case of TiSi2 oxidation, in addition to a different mechanism of growth, the nature of the oxide depends on temperature: almost pure SiO2 for T≳600 °C and a TiO2-SiO2 mixture for T<600 °C. The low temperature regime gives rise to an unexpected high oxide growth rate with respect to the behavior at high temperatures.