Subterahertz hypersound attenuation in silica glass studied via picosecond acoustics

Simon Ayrinhac (1) , Marie Foret (2) , Arnaud Devos (1) , Benoit Ruffle (2) , Eric Courtens (2) , René Vacher (2)

1 IEMN - Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520
2 L2C - Laboratoire Charles Coulomb

We report picosecond acoustic measurements in silica-glass films grown by wet thermal oxidation on a (111) silicon substrate. The longitudinal acoustic phonons are observed over the range from 150 to 300 GHz using an infrared pump and a second harmonic blue probe. The transducer is an aluminum thin film deposited on top. Multiple interference effects are analyzed and fully taken into account. They lead to a signal presenting rapid oscillations as a function of the sample thicknesses. The latter are determined by separate interferometry. Our remarkably precise acoustic attenuation results are found to follow rather well a model combining thermally activated relaxations and anharmonicity. New values for the optical absorption of silicon in the 400-to-500-nm region of the spectrum are obtained as a by-product.

Domaines: Mécanique des matériaux [physics.class-ph]; Acoustique [physics.class-ph]

Simon Ayrinhac, Marie Foret, Arnaud Devos, Benoit Ruffle, Eric Courtens, et al.. Subterahertz hypersound attenuation in silica glass studied via picosecond acoustics. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2011, 83 (1), pp.014204. ⟨10.1103/PhysRevB.83.014204⟩. ⟨hal-00567412⟩