Influence of N-2 gas pressure on the chemical bonds of amorphous carbon nitride films

Abstract

A study on the dependence of the microstructure of CNx films on N-2 gas pressure was conducted in an RF magnetron sputtering system. A significant change in microstructure was observed as gas pressure decreased: the concentration of sp(2) C=N and hydrogenated bonds decreased, while that of sp(3) C-N and sp C=N bonds increased. This implies that low pressure favours the synthesis of CNx films of good mechanical properties. A further investigation using a Langmuir probe and Monte Carlo collision simulations revealed that the energy of ions bombarding the film increased significantly with decreasing gas pressure. This can lead to changes in hydrogen content and chemical bonds in the growing CNx films.