Study of Cu diffusion behavior in carbon rich SiCN:H films deposited from trimethylphenylsilane

• SiC:H and SiCN:H films were prepared by plasma enhanced chemical vapor deposition.
• Trimethylphenylsilane in a mixture with helium and ammonia was used as a precursor.
• The deposited films have dielectric constant close to 3.5.
• The films had a nanoporous structure; the total porosity did not exceed 1.5%.

Amorphous SiCx:H and SiCxNy:H films were grown on Si (100) substrates by plasma enhanced chemical vapor deposition using trimethylphenylsilane as a precursor. Detailed studies including Fourier transformed infra-red spectrometry, elemental analysis, transmission electron microscopy, dielectric constant and porosity investigations, and preliminary Cu diffusion experiments were performed. It was shown that the films contained pores connected by narrow channels with a diameter of 5 Å, and the total porosity did not exceed 1.5%. The film with both low dielectric constant and low porosity was chosen for Cu diffusion barrier experiments. Si/SiCx:H/Cu structure was created and then annealed. The investigation of cross-sectional cut suggested that the film had good barrier properties against copper diffusion.