Diamond films were used as substrates for cubic boron nitride (c-BN) thin f
ilm deposition. The c-BN films were deposited by ion beam assisted depositi
on (IBAD) using a mixture of nitrogen and argon ions on diamond films. The
diamond films exhibiting different values of surface roughness ranging from
16 to 200 nm (in R-rms) were deposited on Si substrates by plasma enhanced
chemical vapor deposition. The microstructure of these c-BN films has been
studied using in situ reflexion electron energy loss spectroscopy analyses
at different primary energy values, Fourier transform infrared spectroscop
y and high resolution transmission microscopy. The fraction of cubic phase
in the c-BN films was depending on the roughness of the diamond surface. It
was optimized in the case of the smooth surface presenting no particular g
eometrical effect for the incoming energetic nitrogen and argon ions during
the deposition. The films showed a nanocrystalline cubic structure with co
lumnar grains while the near surface region was sp(2) bonded. The films exh
ibit the commonly observed layered structure of c-BN films, that is, a well
textured c-BN volume lying on a h-BN basal layer with the (00.2) planes pe
rpendicular to the substrate. The formation mechanism of c-BN films by IBAD
, still involving a h-BN basal sublayer, does not depend on the substrate n
ature. (C) 1999 Elsevier Science S.A. All rights reserved.