Optical, mechanical and etch properties of amorphous carbon nitride films grown by plasma enhanced chemical vapor deposition at room temperature

Amorphous carbon nitride (a-CN) films were grown on Si(1 0 0) and SiO2/Si(1 0 0) substrates by plasma enhanced chemical vapor deposition at room temperature using gas mixtures of CH4 and N2. The as-deposited films showed two bond structures of CN and CN, and with increasing the N2 content the bond structure changed to graphite-like structure. All the samples showed low optical absorption coefficient (k < 0.15) in the wavelength range of 300–800 nm. The a-CN films exhibited a good resistance to etching (i.e. higher selectivity over SiO2), which indicates a potential use of a-CN films as a new hard mask material.