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

摘要

Determination of phosphorus and boron con-centrations in Czochralski-grown silicon wafer-thick sam-ples has been examined by means of low-temperature high-resolution far-infrared transmission measurements with p-polarized light incident at Brewster angle. The measure-ments 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 × 10~(13)-1.6 × 10~(15) atoms cm~(-3) for phos-phorus and of 2.5 × 10~(14)-7.6 × 10~(14) 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 sup-pressed using this incidence. The detection limit of phos-phorus is about 1.2 × 10~(13) atoms cm~(-3) and that of boron is about 4.2 × 10~(13) atoms cm~(-3), P-polarized Brewster angle incidence has made it possible to determine phos-phorus and boron concentrations in wafer-thick samples.