Abstract
The objective of this study was to correlate mechanical properties with the structure and chemistry of silicon-incorporated amorphous hydrocarbon (Si-aC:H) films deposited by reactive sputtering. Hardness and elastic modulus were measured via microindentation, and intrinsic compressive stress was determined from radius-of-curvature measurements using surface mapping microscopy. Film chemistry was investigated with X-ray photoelectron spectroscopy, electron energy-loss spectroscopy, Raman spectroscopy, and attenuated total reflection Fourier transform infrared spectroscopy. Conventional- and high-resolution transmission electron microscopy revealed that the Si-aC:H phase is amorphous and TiC exists at the Si-aC:H/Ti phase boundary. Mechanical properties such as hardness, modulus, and intrinsic stress decreased with increasing Si and H content in the films, for Si/C ≥ 0.04. Measurements show that this is most likely due to a decrease in C-C sp3 bonds, accompanied by an increase in C-Si and C-H bonds. In addition, the Si-aC:H film with Si/C = 0.04 is fundamentally different from the other Si-aC:H films with higher Si and H contents. It is concluded that a film with diamond-like carbon characteristics can be deposited using a low tetramethyl silane (TMS) flow rate, such that Si/C = 0.04 in the film. However, films deposited with higher TMS flow rates (such that Si/C ≥ 0.06 in the films) are more characteristic of amorphous hydrogenated silicon carbide.
| Original language | English |
|---|---|
| Pages (from-to) | 197-206 |
| Number of pages | 10 |
| Journal | Surface and Coatings Technology |
| Volume | 157 |
| Issue number | 2-3 |
| DOIs | |
| State | Published - Aug 22 2002 |
Funding
We would like to thank The Timken Company for providing financial support for this project. Likewise, we thank Wayne Jennings and John Sears from the Center for Surface Analysis of Materials at CWRU; Dorothy Coffey and K.S. Trent for FIB work and TEM sample preparation; Douglas Clouse and J. David Cogdell for radius-of-curvature measurements; Martin Galehouse for mechanical property assistance; Brian Osborn and Alexander Lazarides for assistance in the coating laboratory; and Edward Evans (Department of Chemical Engineering, The University of Akron) for many useful discussions. Research sponsored by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Transportation Technologies, as part of the High Temperature Materials Laboratory User Program, Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the US Department of Energy under contract number DE-AC05-00OR22725. Research at the Oak Ridge National Laboratory SHaRE Collaborative Research Center was supported by the Division of Materials Sciences and Engineering, US Department of Energy, under contract DE-AC05-00OR22725 with UT-Battelle, LLC and through the SHaRE Program under contract DE-AC05-76OR00030 with Oak Ridge Associated Universities.
Keywords
- Diamond-like carbon
- Photoelectron spectroscopy
- Reactive sputtering
- Silicon
- Transmission electron microscopy