Microhardness and other properties of hydrogenated amorphous silicon carbide thin films formed by plasma-enhanced chemical vapor deposition

The objective of this work was to correlate thin film microhardness with composition and other properties of the Si-C system. Compositions varying from 80% Si to 100% C were formed using plasma-enhanced chemical vapor deposition on Si〈100〉 substrates. As the fraction of carbon increases from 23 to 100 at.%, the hardness increases from about 2300 to more than 7000 kgf mm^-2 (Knoop hardness) at 10% penetration of the indenter. The hardness for stoichiometric SiC is also about 7000 kgf mm^-2. At a particular composition the hardness can be maximized by adjusting the deposition parameters to decrease the hydrogen content and to increase the silicon-to-carbon bonding.