Nanomechanical characterization of amorphous hydrogenated carbon thin films

Amorphous hydrogenated carbon (a-C:H) thin films deposited on a silicon substrate under various mixtures of methane– hydrogen gas by electron cyclotron resonance microwave plasma chemical vapor deposition (ECR-MPCVD) was investigated. Microstructure, surface morphology and mechanical characterizations of the a-C:H films were analyzed using Raman spectroscopy, atomic force microscopy (AFM) and nanoindentation technique, respectively. The results indicated there was an increase of the hydrogen content, the ratio of the D-peak to the G-peak (ID/IG) increased but the surface roughness of the films was reduced. Both hardness and Young’s modulus increased as the hydrogen content was increased. In addition, the contact stress–strain analysis is reported. The results confirmed that the mechanical properties of the amorphous hydrogenated carbon thin films improved using a higher H2 content in the source gas.