1. Study of Elastic Anisotropy of Cu Thin Films by Resonant-Ultrasound Spectroscopy Coupled with Laser-Doppler Interferometry and Pump-Probe Photoacoustics
- Author
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Nobutomo Nakamura, Makoto Fujii, Masahiko Hirao, Takeshi Yasui, Hirotsugu Ogi, Hiroshi Tanei, and Hiroki Nitta
- Subjects
Resonant ultrasound spectroscopy ,Diffraction ,Materials science ,Physics and Astronomy (miscellaneous) ,Condensed matter physics ,business.industry ,General Engineering ,General Physics and Astronomy ,Micromechanics ,Monocrystalline silicon ,Interferometry ,Optics ,Thin film ,Anisotropy ,Spectroscopy ,business - Abstract
Understating elastic properties of thin films is a matter of deep interest both in scientific and industrial fields. In this paper, we propose a combination of resonant-ultrasound spectroscopy coupled with the laser-Doppler interferometry and pump-probe photoacoustics for measuring anisotropic elastic constants of deposited thin films. Among the five independent elastic constants, the resonant-ultrasound spectroscopy is sensitive to the in-plane elastic constants, C11, C13, and C66, and pump-probe photoacoustics to the out-of-plane elastic constant, C33. We apply this to Cu thin films deposited on monocrystalline Si substrates by the magnetron-sputtering method. Cu thin films show elastic anisotropy, C33>C11. The cause of this elastic anisotropy is attributed to the textured structure and the columnar structure. These effects are estimated by X-ray diffraction measurements and micromechanics calculations.
- Published
- 2006
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