Characterization of SiCN thin films: experimental and theoretical investigations

Анотація

Silicon carbon nitride (SiCN) thin films were deposited by plasma-enhanced chemical vapor deposition using hexamethyldisilazane at different nitrogen flow rates. Films were investigated by an atomic force microscope, X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, photoluminescence and nanoindentation. It is established that all the films are amorphous. The deposited films consist mostly of the amorphous SiC_x, and SiC_xN_y networks. To interpret film properties, first-principles molecular dynamics simulations of amorphous SiC, SiCN, SiN and Si₃N₄ were carried out. Based on the experimental and theoretical results, it is suggested that the photoluminescence peaks at 583–594 nm and 428–490 nm originate from a-SiC_x and a-SiC_xN_y, respectively. An addition of nitrogen to the gas mixture leads to: a reduction of the roughness of the film surface; an enhancement of blue emission; an increase in nanohardness and elastic modulus.