Chemical interactions in the layered system BC x N y /Ni(Cu)/Si, produced by CVD at high temperature

Abstract

Layered samples Si(100)/C/Ni/BC(x)N(y) and Si(100)/C/Cu/BC(x)N(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(2) and NH(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 H(2) yielded the BC(x)N(y) compound whereas the use of NH(3) led to a mixture of h-BN and graphitic carbon. At the BC(x)N(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 observed between the metal layer and the substrate Si.

Chemical and physical properties in layers and interfaces of nanolayered Si(100)/Ni/BCxNy stacks

“…The single crystal substrate Si(100) was used because it is the most frequently applied carrier material. Ni was chosen as one of the most often discussed metals in the mentioned field, and the BCN layer was selected as a material known to have extraordinary properties tailored by the synthesis conditions . Cubic BCN is expected to be a superhard material whereas hexagonal BCN has potential applications in microelectronics …”