Comparison of in situ and ex situ plasma-treated metalorganic chemical vapor deposition titanium nitride thin films

摘要

Titanium nitride (TiN) thin films deposited by metalorganic chemical vapor deposition, using tetrakis-dimethyl-amino-titanium as a precursor, are known to have high sheet resistivity. A plasma treatment in forming gas ambient is one way of reducing the high sheet resistivity down to that of the films deposited by physical vapor deposition. This plasma treatment is normally done in situ (without breaking the vacuum) immediately after deposition. However, an ex situ (breaking vacuum after deposition) plasma treatment will provide a more economical way of manufacturing in which less time is required in the chemical vapor deposition chamber, hence allowing high deposition throughput. Furthermore, the plasma treatment can be done in a high-pressure chamber, which translates into low cost. In this study, we compared film properties of TiN with in situ and ex situ plasma treatments. Analyses were performed on chemical composition, sheet resistance, amount of Ti atoms, via resistance and reliability using x-ray photoelectron spectroscopy, four-point probe, x-ray fluorescence, and a current-voltage multiprobe. The ex situ plasma treatment was capable of removing carbon from the TiN film, but not without a sacrifice of the reliability and electrical performance of the TiN film. Further development on the ex situ plasma treatment must be made to improve the reliability and electrical performance of the TiN film.