Nuclear magnetic resonance studies of amorphous deuterated silicon nitride thin films

Abstract

Amorphous hydrogenated/deuterated silicon nitride (a-SiN:H,D) thin films were studied by deuteron magnetic resonance (DMR). DMR spectra show two quadrupolar broadened Pake-type doublets with splittings of 65.4 kHz for SiD, and 154 kHz for ND bonds; the ratio of these DMR doublet cusp-splittings ( Δ ND Δ SiD = 2.35 ) is, to within experimental error, equal to the ratio of the squares of the respective bond-stretching frequencies (( ω ND ω SiD ) 2 = 2.36 ), as determined by analysis of Fourier transform infrared spectra. The center frequencies of the SiD and ND DMR doublets are not coincident, but rather are shifted by ∼ 2 kHz, indicating that the SiD and ND groups are interacting, and must therefore be near-neighbors in the amorphous network. This explanation consistent with an interpretation of the shifts in bond-stretching frequencies of IR modes that occur when Si(H)D and N(H)D modes are found in the same film.