Assignment of the Raman active vibration modes of β-Si₃N₄ using micro-Raman scattering

The vibrational modes of the β-Si₃N₄ Raman active bands appearing in the wave number region between 110 and 1100cm^-1 were determined by the polarization and the crystallographic orientation dependence of the Raman intensities of the bands using micro-Raman spectroscopy. The laser beam was focused onto a single grain with the shape of a regular hexagon or elongated hexagon on the sintered ceramic plate. The three intense bands appearing at about 185, 208, and 230cm^-1 were attributed to the vibrational modes of E_2g, A_g, and E_1g, respectively. The remaining peaks were also assigned to the irreducible representations.