Measurement of complex optical constants of a highly doped Si wafer using terahertz ellipsometry

We propose and demonstrate a terahertz (THz) time-domain spectroscopy combined with ellipsometry. The complex optical constants of a Si wafer with low resistivity are deduced from the measurements of the wave forms of reflected s- and p-polarized THz pulses without reference measurement. The obtained dispersion of refractive index above similar to0.2 THz shows good agreement with that predicted by the Drude theory. The complex optical constants deduced by the THz ellipsometry in the low-frequency region are strongly affected by the slight error of the ellipsometric angle originating mainly from the misalignment of the rotation angles of the polarizer and analyzer. (C) 2001 American Institute of Physics.