IDENTIFICATION OF A NEW DEFECT IN SILICON-NITRIDE FILMS

When silicon nitride films are prepared at a high deposition rate, a complicated ESR spectrum appears, which cannot be attributed to Si dangling bonds or N dangling bonds. It is found by the substitution of N-14 with N-15 that the hyperfine interaction with nitrogen nuclei is the origin of the complicated ESR spectrum. With comparison of the observed ESR spectra with the results of a computer simulation and a first-principles calculation, the new defect is designated as a pure p-type unpaired spin strongly localized on two inequivalent nitrogen atoms bonded to each other. Furthermore, we have also observed the change in the ESR spectra originating from the N-pair defect, the N dangling bond and the Si dangling bond in the N-14 and N-15 samples with ultraviolet soaking after high-temperature annealing.