Dual low pressure plasma process for SiCN:H thin films deposition: A comparative study

SiCN:H thin films have large possibilities of applications due to their versatile chemical and physical properties. Plasma Assisted Chemical Vapor Deposition (PACVD) process widely used for SiCN:H deposition. Here we discuss on the potentialities of dual Electron Cyclotron Resonance (ECR) and Radio Frequency Magnetron Sputtering (rf MS) plasmas coupling for SiCN:H deposition in Ar/N2/Si(CH3)4 gas mixture. The study is carried out by varying the autopolarisation voltage Vbias of the silicon target. ECR plasma gives low deposition growth rate about 50 nm/h. The films are transparent. SiCN nanopillars with high aspect ratio are obtained. Rf MS plasma gives high deposition growth rate up to 2200 nm/h. The films are opaque in the near UV and transparent in the visible depending on their thickness. The optical index at 630 nm is 1.95, the Tauc's band gap is 3.0 eV and do not change with Vbias. Dual ECR/rf MS plasma gives high deposition growth rate up to 2300 nm/h. The films are transparent. The optical index varies between 1.7 and 2.05 at 630 nm and the Tauc's band gap decreases linearly between 4.75 and 3.4 eV with Vbias. Dual ECR/rf MS plasma coupling is a very promising PACVD process for thin films deposition. •ECR plasma permit to obtain amorphous SiCN:H nano pillars suitable for catalysis or other applications.•RF magnetron sputtering (rf MS) with silicon target in Ar/N2/Si(CH3)4 gas mixture (process B) permit to obtain high growth rate of 2200 nm/h for an autopolarisation voltage Vbias≈200 V. Very low change in optical parameters with Vbias.•High deposition growth rate up to 2300 nm/h is obtained with dual ECR/rf MS plasma gives. Good transparency of the thin films from the near UV to near IR is obtained. A linear modulation of the optical parameters vs Vbias is obtained.