Optical determination of mobility and carrier concentration in heavily doped polycrystalline silicon

Abstract

Optical absorption of phosphorus‐doped polycrystalline Si films observed at photon energies below the energy gap has been interpreted in terms of free‐carrier absorption, which obeys the Drude theory. As a result, we can simultaneously determine conductivity, electron mobility, and carrier concentration of heavily doped polycrystalline Si films from their optical transmission spectra alone. The new technique offers a contactless measurement of electrical properties for heavily doped polycrystalline Si thin films.