The atomic structure, energy, stability, vibrational spectra, and infrared absorption intensities of major intrinsic nitrogen-related defects in nitrogen doped silicon crystals were investigated using ab initio density functional theory and semi-empirical quantum mechanics methods. The defects that were of interest were nitrogen-vacancy-oxygen complexes which were believed to affect oxygen precipitation and void formation as well as nitrogen concentration measurement in nitrogen-doped silicon. Several chemical reactions involving nitrogen, Si vacancies and oxygen interstitial were studied. After relaxation, the local vibrational modes of each complex were calculated within the harmonic oscillator approximation and the infrared absorption intensities were evaluated from the dipole moment derivatives. By cross-correlating the stability and the infra-red active lines of the defect, and by taking into consideration the symmetry group of each complex, it was possible to emphasize which nitrogen-related complexes were likely to control oxygen precipitation and void formation and to propose a new calibration relationship for nitrogen concentration measurements in nitrogen-doped Czochralski and float-zone silicon wafers.

A Density Functional Theory Study of the Atomic Structure, Formation Energy, and Vibrational Properties of Nitrogen-Vacancy-Oxygen Defects in Silicon. F.S.Karoui, A.Karoui: Journal of Applied Physics, 2010, 108[3], 033513