CHEMICAL-VAPOR-DEPOSITION OF DIAMOND ONTO IRON-BASED SUBSTRATES - THEUSE OF BARRIER LAYERS

When Fe is exposed to the plasma environment suitable for the chemical vapour deposition of diamond, the surface is rapidly covered with a t hick layer of graphitic soot and C swiftly diffuses into the Fe substr ate. Once the soot reaches a critical thickness, diamond films nucleat e and grow on top of it. However, adhesion of the film to the substrat e is poor owing to the lack of structural integrity of the soot layer. A thin coating of TIN on the Fe can act to prevent diffusion and soot formation. Diamond readily grows upon the TiN via an a-C interface la yer, but the a-C-TiN interface is weak and delamination occurs at this interface. In order to try and improve the adhesion, the use of a hig h dose Ti implant was investigated to replace the TiN coating.