Characterization of a N2/CH4 Microwave Plasma With a Solid Additive Si Source Used for SiCN Deposition

Microwave plasma assisted chemical vapour deposition of CH4/N2 gas mixture using an additive solid silicon is used to synthesize SiCN. To better understand the mechanisms involved, species such as C, Si, NH, CN, C2 and N2 are observed by means of optical emission spectroscopy. In situ Fourier transform infrared spectroscopy (FTIR) is used as a plasma diagnostic and CH4, NH3, HCN and C2H2 have been detected. Deposits are achieved at various CH4 ratios (1, 4 and 8%) and analysed by means of scanning electron microscopy, energy dispersion X-ray spectroscopy and FTIR spectroscopy. Adding a silicon source permits to obtain thicker layers confirming the major role of Si in the carbonitride deposition process. Deposits obtained at 8% of CH4 have a composition about 35% of Si, 30% C and 30% N and showed evidence of ternary SiCN system.