Investigation of the complex permittivity of n-type silicon at millimeter wavelengths

Measurements of the complex permittivity at 107.3 GHz of n-type silicon specimens in the 5–50 Ω cm resistivity range were made using a free space reflection/transmission technique. Reflectance measurements on specimens in the 0.004–5 Ω cm range were obtained. All measurements were compared with a single relaxation time Drude model and a more complete model that was developed which includes Fermi–Dirac statistics and energy dependent lattice and impurity scattering. Although the Drude model was found to reliably predict the complex permittivity of n-type silicon over a specified range of resistivity, it has limitations which are discussed.