Experiment and simulation of the compositional evolution of Ti-B thin films deposited by sputtering of a compound target
- Christian Doppler Laboratory for Advanced Hard Coatings, Department of Physical Metallurgy and Materials Testing, University of Leoben, Franz-Josef-Str. 18, 8700 Leoben (Austria)
- Materials Chemistry, RWTH Aachen University, Kopernikusstr. 16, D-52074 Aachen (Germany)
- Hahn-Meitner-Institut Berlin GmbH, Department SF4, Glienicker Str. 100, D-14109 Berlin (Germany)
- Institute of Ion Beam Physics and Materials Research, Forschungszentrum Dresden-Rossendorf, P.O. Box 510119, D-01314 Dresden (Germany)
The evolution of the coating stoichiometry with pressure, target-substrate distance, and angle was analyzed for dc sputtering of Ti{sub x}B (x=0.5, 1, 1.6) compound targets by elastic recoil detection analysis. For an investigation of the underlying fundamental processes primarily Ar was used as sputter gas. Additionally, the effect of a reactive gas (N{sub 2}) as well as bias voltage (floating up to -200 V) was briefly cross-checked. For deposition along the target normal (90 deg.) a pronounced Ti-deficiency of up to 20% is detected. Increasing the pressure or distance from 0.5 to 2 Pa and from 5 to 20 cm, respectively, leads to an almost equivalent linear increase in Ti/B ratio surpassing even the target composition. Off-axis depositions at lower angles (30 deg. and 60 deg.) on the other hand result in a higher Ti/B ratio. This is consistent with results obtained from Monte Carlo simulations combining the respective emission characteristics from the sputter process as well as the gas-phase transport. Hence, the pressure, distance, and sample position induced changes in chemical film composition can be understood by considering gas scattering and the angular distribution of the sputtered flux. The theoretically determined transition from a directional flux to thermal diffusion was experimentally verified by mass-energy analysis of the film-forming atoms.
- OSTI ID:
- 21182619
- Journal Information:
- Journal of Applied Physics, Vol. 104, Issue 6; Other Information: DOI: 10.1063/1.2978211; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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