SICN AMORPHOUS MATERIALS CHEMICAL-VAPOR-DEPOSITED USING THE SI(CH3)(4)-NH3-H-2 SYSTEM

Elaboration of amorphous SiCN materials was performed using a conventional thermaly activated CVD at 1000-1200 degrees C from the TMS-NH3-H-2 system. The influence on the deposition rate and the composition was investigated using an experimental design by varying deposition temperature, pressure and NH3 flow rate. A set of 16 samples SiCxNy with x/y ranged from 0.04 to 1.69 was prepared. Accurate determination of the elemental compositon required EPMA-WDS and XPS and occasionally RBS analyses. The chemical bonding system am investigated by XPS and Raman spectroscopy. Comparisons between CVD prepared silicon carbide and nitride reference samples and the SiCxNy materials were achieved. It was concluded that for x y < 0.15, Si-N was predominant, whereas for x y greater than or equal to 0.86, the amorphous deposits mainly contain Si-N and Si-C, and additionally carbon bonds including C-Si and C-C, and probably a rather low C-N contribution. Raman study shown that C-C bonding could be related to a carbon excess acting as a binder in-between the tetrahedral networks of Si-C and Si-N. The first results of EXELFS concerning a carbon poor deposit shown that Si has a first coordination shell similar to that of Si3N4.