Investigating the elastic properties of β-SiC films

Abstract

Direct elastic properties measurements of β-SiC films have been made using the interferometric strain gage displacement (ISDG) technique and compared with data acquired by the Brillouin light scattering (BLS) technique. BLS permits to selectively determine the three independent elastic constants ( c 11 = 395 GPa; ( c 11 − c 12 )/2 = 136 GPa and c 44 = 236 GPa) of a β-SiC single crystal epitaxial film from the analysis of a number of different surface acoustic modes. The calculated Voigt average values of the elastic constants for the 〈1 1 1〉 textured polycrystalline films ( C 11 = 500 GPa, C 33 = 534 GPa, C 44 = 166 GPa, C 66 = 201 GPa, C 13 = 62 GPa) using the single crystal constants provides good agreement with experimental results on Young’s modulus measured by the ISDG technique. Nevertheless, BLS gave more accurate values of Poisson’s ratios.