Structure and Mechanical Performance of Nitrogen Doped Diamond-like Carbon Films

Nitrogen doped diamond-like carbon (DLC:N) films were prepared by electron cyclotron resonance chemical vapor deposition (ECR-CVD) on polycrystalline Si chips. Film thickness is about 50 nm. Auger electron spectroscopy (AES) was used to evaluate nitrogen content, and increasing N2 flow improved N content from 0 to 7.6%. Raman and X-ray photoelectron spectroscopy (XPS) analysis results reveal N-sp3C and N-sp2C structure. With increasing the N2 flow, sp3C decreases from 73.74% down to 42.66%, and so does N-sp3C from 68.04% down to 20.23%. The hardness decreases from 29.18 GPa down to 19.74 GPa, and the Young's modulus from 193.03 GPa down to 144.52 GPa.