Elastic Properties of Several Silicon Nitride Films
We have measured the internal friction (Q{sup -1}) of amorphous silicon nitride (a-SiN{sub x}) films prepared by a variety of methods, including low-pressure chemical-vapor deposition (LPCVD), plasma-enhanced chemical-vapor deposition (PECVD), and hot-wire chemical-vapor deposition (HWCVD) from 0.5 K to room temperature. The measurements are made by depositing the films onto extremely high-Q silicon double paddle oscillator substrates with a resonant frequency of {approx}5500 Hz. We find the elastic properties of these a-SiN{sub x} films resemble those of amorphous silicon (a-Si) films, demonstrating considerable variation which depends on the film growth methods and post deposition annealing. The internal friction for most of the films shows a broad temperature-independent plateau below 30 K, characteristic of amorphous solids. The values of Q{sup -1}, however, vary from film to film in this plateau region by more than one order of magnitude. This has been observed in tetrehedrally covalent-bonded amorphous thin films, like a-Si, a-Ge, and a-C. The PECVD films have the highest Q{sup -1} just like a normal amorphous solid, while LPCVD films have an internal friction more than one order of magnitude lower. All the films show a reduction of Q{sup -1} after annealing at 800 C, even for the LPCVD films which were prepared at 850 C. This can be viewed as a reduction of structural disorder.
- Research Organization:
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC36-08GO28308
- OSTI ID:
- 978490
- Resource Relation:
- Conference: Amorphous and Polycrystalline Thin-Film Silicon Science and Technology - 2007: Proceedings of the Materials Research Society Symposium, 9-13 April 2007, San Francisco, California; Materials Research Society Symposium Proceedings, Vol. 989; Related Information: Paper No. 0989-A22-01
- Country of Publication:
- United States
- Language:
- English
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