Microcomposite and Nanocomposite Structures from Chemical Vapor Deposition in the Silicon-Titanium-Carbon System

Microcomposite and nanocomposite structures composed of SiC‐TiC and C have been prepared by chemical vapor deposition at atmospheric pressure (APCVD) from an initial gaseous mixture with the composition C4H10‐SiH2Cl2‐TiCl4‐H2. Transmission electron microscopy reveals that deposits with a nanocomposite structure consist of a network of 10‐nm‐thick needles surrounded by small areas of amorphous carbon. The relative amounts of TiC and SiC as well as the microstructure depend on the SiH2Cl2 and TiCl4 content in the initial gas‐phase mixture. The variations of composition of the deposits are in good accordance with the thermodynamic calculations. Amorphous carbon is always present in the deposits. This amount can be lowered to 1 at.% at low deposition temperatures but, at such a concentration, still has a great influence on microhardness. The variation of the preferred orientation of crystals is also discussed with respect to the composition of the samples and the deposition temperature.