The strain force near the boundary between the c-BN phase and the sp(2)-bon
ded BN interlayer is thought to increase lattice spacing between h-BN/t-BN
(0002) planes of the interlayer and cause Feeling of c-BN films. Based on t
his concept, a new BN buffer layer that enhances c-BN adhesion is examined.
This buffer is nearly stoichiometric in composition, tensile in stress and
contains hexagonal planes that are not aligned normal to the substrate sur
face. The improvement of c-BN adhesion is attributed to such a disordered m
icrostructure with covalent B-N bonds randomly oriented in a three-dimensio
nal manner. These covalent bonds, particulary those aligned in the directio
n parallel to the substrate surface? are important for tolerating the strai
n force that induces peeling of c-BN films. We speculate that similar coval
ent bends are present in many previously reported buffer layers that improv
e c-BN adhesion. Likewise, the tensile stress in our buffer layer is consid
ered to compensate partially for the compressive stress in c-BN films and t
o improve the adhesion as well. A hybrid deposition procedure for growing a
dhesive c-BN films is proposed.