Influence of disordered covalent bonds in a BN buffer layer on improving adhesion of c-BN films

Yap, YK Yoshimura, M Mori, Y Sasaki, T

Yk. Yap et al., Influence of disordered covalent bonds in a BN buffer layer on improving adhesion of c-BN films, NEW DIAM FR, 10(4), 2000, pp. 201-212

47

INGLESE

Article

Apllied Physucs/Condensed Matter/Materiales Science","Material Science & Engineering

NEW DIAMOND AND FRONTIER CARBON TECHNOLOGY

1344-9931 → ACNP

10

4

2000

201 - 212

ISI

1344-9931(2000)10:4<201:IODCBI>2.0.ZU;2-#

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.