Silicon Carbon Nitride Thin Films Deposited by Pulsed Microwave Plasma Assisted Chemical Vapour Deposition

Abstract

Objective: This study aimed to synthesize crystalline silicon carbon nitride thin films by pulsed microwave plasma assisted chemical vapour deposition in N 2 /CH 4 gas mixture on silicon substrates.Methodology: Prior to deposition, the pulsed microwave discharges were analyzed in situ by Time Resolved Optical Emission Spectroscopy (TROES).The behavior of the emissive radicals present in the plasma is observed during the discharge and post-discharge phases.The study of the pulsed plasma shows that, in the post-discharge, CN and C 2 radicals continue their emission and fluorescence was observed which is explained by the energy transfer from the metastable states of N 2 to these species.The films were realized according to the pulse parameters and were then characterized by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), in order to observe their morphology and structures.Results: These images showed that films have nano-crystalline structure.The films chemical composition and their bonding structure are also analyzed by X-ray Photoelectrons Spectroscopy (XPS).The films contain C, N, Si and a few quantity of O 2 coming from their exposure to atmosphere after deposition.The silicon in the films comes from the etching of the silicon substrate.The observation of C1s, N1s and Si2p levels showed the presence of C-N, Si-C and Si-N bonds.Conclusion: The pulsed microwave mode is very advantageous for the molecules dissociation compared to the continuous mode.It permitted us to follow the growth and etching kinetic in order to control the films chemical composition.Thus, we obtained 16% of nitrogen in the film with a post-discharge duration of 3 msec.