Chemical interactions in the layered system B[C.sub.x][N.sun.y]/Ni/Si, produced by CVD at high temperature

Layered samples Si(100)/C/Ni/B[C.sub.x][N.sub.y] and Si (100)/C/Cu/B[C.sub.x][N.sub.y] were produced by physical vapor deposition of a metal (Ni, Cu, resp.) and low-pressure chemical vapor deposition of the boron carbonitride on a Si(100) substrate. Between the Si and the Ni (Cu) and on the surface of the Ni (Cu) layer, thin carbon layers were deposited, as a diffusion barrier or as a protection against oxidation, respectively. Afterwards, the surface carbon layer was removed. As precursor, trimethylamine borane and, as an auxiliary gas, [H.sub.2] and N[H.sub.3] were used, respectively. The chemical compositions of the layers and of the interfaces in between were characterized by total-reflection X-ray fluorescence spectrometry combined with near-edge X-ray absorption fine-structure spectroscopy, X-ray photoelectron spectroscopy, and secondary ion mass spectrometry. The application of H2 yielded the B[C.sub.x][N.sub.y] compound whereas the use of NH3 led to a mixture of h-BN and graphitic carbon. At the B[C.sub.x][N.sub.y]/metal interface, metal borides could be identified. At the relatively high synthesis temperature of 700 °C, broad regions of Cu or Ni and Si were ob-served between the metal layer and the substrate Si. Keywords Boron carbonitride/metal/silicon-layered system * Interfaces * Near-edge X-ray absorption fine-structure spectroscopy * X-ray photoelectron spectroscopy * Secondary ion mass spectroscopy