Effect of nitrogen flow rate on the mechanical properties of CVD-deposited SiCN thin films

Silicon carbonitride (SiCN) thin films were deposited on p-Si (100) substrates with different $$\hbox {N}₂$$ flow rates using SiC and $$\hbox {Si}₃\hbox {N}₄$$ powder precursors by chemical vapour deposition. To investigate the structural, vibrational and mechanical properties, the SiCN thin films were characterized by atomic force microscopy, Raman spectroscopy, X-ray diffraction (XRD), Fourier transform infrared and nanoindentation techniques. The XRD results reveal nanocrystals embedded with amorphous networks in the SiCN thin films. An increase in the $$I_{\mathrm{D}}/I_{\mathrm{G}}$$ ratio with an increase in the $$\hbox {N}₂$$ flow rate indicated the increase of $$\hbox {sp}³$$ bonds in the SiCN thin film. The hardness (H), Young’s modulus (E), plasticity index (H / E) and $$(H³/E²)$$ increase with an increase in the $$\hbox {N}₂$$ flow rate.