NITROGEN-OXYGEN COMPLEXES IN SILICON STUDIED BY PHOTOTHERMAL IONIZATION SPECTROSCOPY

High-resolution photothermal ionization spectroscopy has been performed on silicon grown in a nitrogen environment by the Czochralski technique for the first time. Three shallow donors related to the complexes of nitrogen and oxygen impurities D(N-O-3), D(N-O-4), and D(N-O-5) have been observed. Previously unresolved transitions related to the excited states higher than 3p +/- for D(N-O)s are observed in the spectra as well. The ionization energies of D(N-O)s have been accurately determined as 36.16, 36.41, and 37.37 meV, respectively. In addition, two previously unidentified donor levels found in the absorption spectra of silicon crystal involving nitrogen and oxygen are identified as originating from the splitting of the ground state of phosphorus.