Surface Roughening during Titanium Silicide Formation: A Comparison between Si(100) and Poly-Si Substrates

We demonstrate the formation of TiSi2 for Ti films deposited on undoped Si(100) substrates leads to rougher surfaces than for Ti films deposited on undoped poly-Si substrates. The successive formations of TiSi2 C49 (high resistivity) and C54 (low resistivity) phases from titanium films deposited on either Si(100) or poly-Si substrates were monitored in situ during rapid thermal annealing using elastic light scattering, x-ray diffraction and resistance measurements. For both types of substrates, the rouhghening occurs only during the formation of the first TiSi2 phase (C49) by light scattered from lateral length scales of 0.5um. Atomic force microscopy (AFM) images, quantified using Fourier filtering, are consistent with the light scattering results.