Inter-diffusion of Hafnium and Silicon as studied by sputter depth profiling and X-ray Photoelectron Spectroscopy

The Hf/Si interface has been characterized by x-ray photoelectron spectroscopy. Thin films (thicknesses of about 500 nm) of hafnium were deposited on a silicon substrate. Prior to the sample deposition the silicon substrate was cleaned by HF for one minute and then loaded into the deposition chamber. The e-beam method was used for the deposition. The samples were annealed for 30 min at temperatures of 200 and 300°C. The inter-diffusion of hafnium and silicon was investigated by sequential sputter depth profiling and x-ray photoelectron spectroscopy. The x-ray photoelectron spectral data were recorded in the Hf 4f and Si 2p regions. The areas under the curve were used to determine the atomic concentration of the constituents. The interdiffusion was analyzed by the Matano-Boltzmann’s procedure using the Fick’s second law. The interdiffusion coefficients as determined from the data have been correlated with the annealing temperature.