Summary: Tungsten Allylimido Complexes Cl4(RCN)W(NC3H5) as
Single-Source CVD Precursors for WNxCy Thin Films.
Correlation of Precursor Fragmentation to Film Properties
Omar J. Bchir, Kelly M. Green, Hiral M. Ajmera, Elizabeth A. Zapp,
Timothy J. Anderson,*, Benjamin C. Brooks,,§ Laurel L. Reitfort, David H. Powell,
Khalil A. Abboud, and Lisa McElwee-White*,
Contribution from the Departments of Chemistry and Chemical Engineering,
UniVersity of Florida, GainesVille, Florida 32611
Received October 11, 2004; E-mail: email@example.com; firstname.lastname@example.org.
Abstract: A mixture of the tungsten allylimido complexes Cl4(RCN)W(NC3H5) (3a, R ) CH3 and 3b, R )
Ph) was tested as a single-source precursor for growth of tungsten nitride (WNx) or carbonitride (WNxCy)
thin films. Films deposited from 3a,b below 550 °C contained amorphous -WNxCy, while those deposited
at higher temperatures were polycrystalline. Film growth rates from 3a,b ranged from 5 to 10 Å/min over
a temperature range of 450-650 °C, and the apparent activation energy for film growth was 0.15 eV. A
plot of the Ea values for deposition from Cl4(RCN)W(NR) [R ) Ph, iPr, allyl] against the N-C imido bond
strengths for the analogous amines RNH2 is linear, implicating cleavage of the N-C bond as the rate-
determining step in film growth. The correlation of mass spectral fragmentation patterns for Cl4(RCN)W-
(NR) with film properties such as nitrogen content supports the significance of facile N-C bond cleavage
in film growth.