Normal modes of local vibration of N in Czochralski material were analyzed by using the molecular orbital calculation. Wave-number and dipole were compared to the observed infra-red absorption spectra. It was confirmed that the observed peaks at 963 and 764/cm were due to a normal vibration mode of anti-symmetrical stretching of BF3-type planar 4-atom molecule and H2O-type non-linear 3-atom molecule, respectively. Those modes in the N¯N¯O structure and N¯N¯O¯O structure were identified and the 1026/cm peak was assigned to the Si¯O¯Si vibration. The results help to establish the total N concentration in Czochralski Si.

Analysis of Localized Vibration of Nitrogen in Silicon. I.Ohkubo, T.Mikayama, H.Harada, N.Inoue: Materials Science and Engineering B, 2002, 91-92, 164-6