Nanocrystalline Diamond Growth on Different Substrates

Thin nanocrystalline diamond (NCD) films were grown by microwave plasma chemical vapor deposition (MWCVD) on silicon wafers coated with polycrystalline diamond (PCD), cubic boron nitride and titanium nitride layers. A methane/ nitrogen mixture with a methane concentration of 17% was used as precursor, the substrate temperature was kept at 600oC, the working pressure was 38 mbar and the MW input power 1 kW. In the case of PCD and c-BN no pretreatment of the substrates was applied in order to deposit NCD, while no growth was observed on the TiN substrates without pretreatment in suspension of diamond powder (average grain size of 250 nm) in n-pentane which enhanced the diamond nucleation. The morphology of the films was studied by scanning electron microscopy (SEM) which revealed closed and uniform layers. The results from X-ray diffraction (XRD) showed that all films were composed of diamond crystallites with grain sizes of 3-5 nm. The Raman spectra of NCD were similar indicating that the substrate has no substantial influence of the bonding structure of the films. The mechanical properties of the films were also investigated. It was found that the hardness and the Young's modulus of NCD on PCD and c-BN determined by nanoindentations were higher than those of NCD on TiN due to the influence of the nature of the substrate. In contrary, the best adhesion was observed for the latter films most probably as a result of the better adhesion between the silicon substrate and the intermediate layers.

KULISCH W.;  POPOV C.;  VORLICEK V.;  GIBSON Peter;  FAVARO G.; 

2007-01-19

ELSEVIER SCIENCE SA

JRC33182

https://publications.jrc.ec.europa.eu/repository/handle/JRC33182,   

10.1016/j.tsf.2006.07.163,