Elastic properties of thin h-BN films investigated by Brillouin light scattering

Hexagonal BN films have been deposited by r.f.-magnetron sputtering with si multaneous ion plating. The elastic properties of the films grown on silico n substrates under identical coating conditions have been determined by Bri llouin light scattering from thermally excited surface phonons. Four of the five independent elastic constants of the deposited material are found to be c(11) = 65 GPa, c(13) = 7 GPa, c(33) = 92 GPa and c(44) = 53 GPa exhibit ing an elastic anisotropy c(11)/c(33) of 0.7. The Young's modulus determine d with load indentation is distinctly larger than the corresponding value t aken from Brillouin light scattering. This discrepancy is attributed to the specific morphology of the material with nanocrystallites embedded in an a morphous matrix. (C) 1999 Elsevier Science S.A. All rights reserved.