Our understanding of the role of the initial surface on atomic layer
deposition (ALD) of Cu diffusion barrier materials is limited by the
complexity of the sequential reactions and the heterogeneous nature of
typical dielectric substrates. The atomically controlled surface chemistry
of self-assembled monolayers (SAMs) provides a means of creating model
substrates for ALD. Here we report on ALD of WCxNy
films on SAMs derived from bromoundecyltrichlorosilane adsorbed on silicon
dioxide. The as-prepared SAM is macroscopically ordered with the expected
Br-termination and has a well-defined chemical composition as determined by
contact angle measurements and X-ray photoelectron spectroscopy,
respectively. Temperature programmed desorption spectroscopy confirms that
the SAM is stable to 550°C. It survives multiple cycles of ALD at 300°C as
evidenced by the detection of mass fragments characteristic of the alkyl
chain and supported by the persistence of a Br 2p peak at 71 eV. X-ray
fluorescence, ellipsometry and atomic force microscopy reveal that the
underlying SAM influences WCxNy film coverage, thickness, and
morphology.