Mechanical properties of PECVD a-SiC:H thin films prepared from methyltrichlorosilane

PECVD amorphous hydrogenated silicon carbide (a-SiC:H) thin films have been deposited from methyltrichlorosilane (MTCS) onto (100) Si substrates varying a substrate temperature (TS) from 200 to 600 °C. The use of MTCS as a precursor allows us to decrease the cost of the process and make it more environment-friendly as compared with the traditional silane–methane mixture. Infrared spectra of the high-temperature films point to an increase in the Si–C bond density and a decrease in the Si–H and C–H bond densities, although the noticeable traces of C–H fragments are detected. An increase in TS leads to the enhancement of both the nanohardness (H) and elastic modulus (E). The values of H and E reach as high as 21 and 184 GPa, respectively, at TS = 600 °C. The films deposited at 300–400 °C exhibit the highest abrasive wear resistance. X-Ray diffraction analysis shows that the above a-SiC:H films can contain small crystalline (6H-SiC, 3C-SiC) islets in the amorphous matrix. Our findings show that wear resistance of a-SiC:H films does not always correlate with hardness and elastic modulus.