Thin films (10 - 150 nm) of a-C:H on glass and silicon substrates have been studied utilizing a confocal micro Raman system using an argon ion laser (514.5 nm) and helium-neon (He-Ne) laser (632.8 nm) for sample excitation. The relationship between the measured Raman spectrum and the film thickness, substrate material, laser intensity and exposure time, have been assessed. From this, the dominant variables have been identified. Microstructural changes in the form of the growth of graphitic crystallites, similar to that of thermally annealed samples, have been observed. For longer laser irradiation exposure times this graphitic component decreases, revealing an amorphous carbon structure, possibly containing some tetrahedrally-bonded carbon. Optical microscopy and topographical atomic force microscopy also highlight the range of laser ablated conditions that result.
Bibliographical noteFunding Information:
This project is supported by Seagate Technology (Ireland) Ltd. and the Industrial Research and Technology Unit for Northern Ireland. The authors would also like to acknowledge instruments SA for their technical support and Mr. David Kennedy and Dr. Patrick Lemoine for their technical assistance.
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- Diamond-like carbon
- Hydrogenated amorphous carbon (a-C:H)
- Laser irradiation
- Raman scattering