Optical determination of shallow carrier profiles using Fourier transform infrared ellipsometry

Dopant profiles were determined by ex situ Fourier transform infrared variable-angle spectroscopic ellipsometry. The technique exploits carrier absorption in the mid-infrared spectral range and combines the sensitivity of ellipsometry with a simple Drude free carrier absorption model to determine the carrier profile, The noncontact, nondestructive nature of the measurement suggests both ex situ and in situ monitoring and control applications. In this study, the carrier profiles were modeled as graded multilayers that can be constrained to a given functional form (Gaussian, erfc, etc.) when desired. Baron and arsenic implanted silicon wafers that were rapid thermal anneal and furnace annealed were measured and compared to spreading resistance probe data. (C) 1998 American Vacuum Society.