ИСТИНА

his work compares spectral properties of crystalline and porous silicon samples. Crystalline silicon <100> under investigation was prepared by Czochralsky method. Porous silicon 10-100 µm films were synthesized by means of electro etching on p-Si <100> substrates doped with boron. Dependent on current density while etching and conductivity of the substrate, films of different porosity were obtained. Measured dependencies of amplitude passed through and reflected from the samples on the frequency of radiation in near and far infrared regions provide information on vibrational modes present in the samples. Terahertz spectra obtained for crystalline silicon in the temperature range of 50-18 K enable us to observe a specific narrow absorption line at 29.2 cm-1. This line accounts for SiO2 modes which are presented in crystalline silicon by impurity oxygen atoms sited between two neighbor silicon atoms.