Oxidation of tantalum silicide thin films in an RF oxygen plasma

Abstract We have investigated the RF plasma oxidation at floating potential of tantalum silicide with a Si:Ta ratio of 2.2 on 〈100〉 silicon. The oxidation was carried out in the 500–800°C temperature range. Rutherford backscattering spectrometry and nuclear reaction analysis have been used to study the composition of the samples and to determine the oxide growth kinetics. The oxidation rate was found to be controlled by the diffusion of the oxidizing species through the oxide. The oxidation leads to the growth of a pure silicon oxide film on surface. The growth of pure SiO 2 is postulated to occur by the supply of silicon atoms from both the substrate and the silicide layer. The existence of a diffusion barrier of SiO 2 between the silicon and the silicide avoids the supply of free silicon from the substrate. In this case, after the initial growth of SiO 2 , the formation of an oxide layer where both silicon and metal atoms are present was observed.