Optical and electrical properties of heavily phosphorus-doped epitaxial silicon layers

Abstract

The index of refraction and the absorption coefficient of epitaxial Si films were measured as a function of wavelength (0.4–0.75 μm) and with phosphorus doping as parameter. These optical constants, obtained from reflectance and transmittance measurements of epitaxial Si films on sapphire substrates, were compared with literature values and with recent measurements of heavily P-doped poly-Si films. In heavily P-doped films (near the solid solubility) of poly and epi Si the absorption coefficients are about the same. Also, the Hall mobilities were measured as a function of carrier concentration in the range 6×1019–4×1020/cm3 and compared with the mobilities derived from infrared reflectance measurements on both poly and epi Si.