Measurements of phosphorus and boron concentrations in Czochralski silicon wafer-thick samples by p-polarized Brewster incidence far-infrared transmission

Determination of phosphorus and boron concentrations in Czochralski-grown silicon wafer-thick samples has been examined by means of low-temperature high-resolution far-infrared transmission measurements with p-polarized light incident at Brewster angle. The measurements were taken at about 8.7 K with a spectral resolution of 0.5 cm−1 under halogen light illumination. Linear correlations are clearly obtained between the absorption coefficients of several phosphorus and boron transitions and their concentrations, which are approximately in the range of 7.7 × 1013–1.6 × 1015 atoms cm−3 for phosphorus and of 2.5 × 1014–7.6 × 1014 atoms cm−3 for boron. The correlations are obtained regardless of the surface processing conditions of the samples. These are because interference fringes due to internal multiple reflections in wafer-thick silicon samples are almost suppressed using this incidence. The detection limit of phosphorus is about 1.2 × 1013 atoms cm−3 and that of boron is about 4.2 × 1013 atoms cm−3. P-polarized Brewster angle incidence has made it possible to determine phosphorus and boron concentrations in wafer-thick samples.