| AVS 63rd International Symposium & Exhibition | |
| Thin Film | Friday Sessions |
| Session TF-FrM |
| Session: | CVD, ALD and Film Characterization |
| Presenter: | John Abelson, University of Illinois at Urbana Champaign |
| Authors: | P. Zhang, University of Illinois at Urbana Champaign E. Mohimi, University of Illinois at Urbana Champaign T. Talukdar, University of Illinois at Urbana Champaign G.S. Girolami, University of Illinois at Urbana Champaign J.R. Abelson, University of Illinois at Urbana Champaign |
| Correspondent: | Click to Email |
The precursor Fe(CO)5 can be used to deposit Fe and Fe alloy thin films by CVD. However, at temperatures of 200-300°C this system exhibits undesirable behaviors – a reduction in growth rate with increasing temperature, a change in morphology from faceted to irregular, and a self-limiting film thickness – that make film growth very difficult to control and reproduce. We hypothesize that decomposition of CO ligands poisons the growth surface with graphitic carbon, on which further precursor reaction is suppressed.
Here, we report a novel solution based on surface chemistry: injection of NH3 along with Fe(CO)5 eliminates the poisoning effect, i.e., Fe CVD becomes stable and reproducible in the temperature range of 200-300°C with little change in morphology or growth rate. We propose that NH3 removes CO from the growth surface before it can decompose based on mechanisms that were previously investigated for CO on static Fe surfaces[1].
We report that co-flow of NH3 entirely restores the growth rate and morphology of pure Fe and of FexCo1-x films. The use of NH3 may be applicable to other set carbonyl-based CVD precursors.
1. Johnston, Colin, Norman Jorgensen, and Colin H. Rochester. "Infrared study of ammonia–carbon monoxide reactions on silica-supported iron catalysts."Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases 84.10 (1988): 3605-3613.