Oxidation of tantalum disilicide/polycrystalline silicon structures in dry O2

The oxidation kinetics of tantalum disilicide/polycrystalline silicon composite structures in a dry O2 ambient have been investigated. The formation of silicon dioxide films on the tantalum disilicide was observed for all temperatures evaluated in the range of 800–1000 °C. The oxidation is postulated to occur as a result of the diffusion of silicon from the underlying polycrystalline silicon film through the TaSi2 film. The linear oxidation rate constant is substantially higher than that for the oxidation of single crystal silicon. The oxidation rate was found to be primarily controlled by the diffusion of the oxidant species through the forming oxide resulting in parabolic growth. The parabolic rate constant determined is similar to that obtained in the oxidation of single-crystal silicon with an activation energy of approximately 28 kcal/mol. This value has been previously related to the diffusivity of oxygen through fused silica.