Tailored amorphous silicon carbide barrier dielectrics by nitrogen and oxygen doping

Abstract The effects of N or O doping into hydrogenated amorphous silicon carbide (a-SiC:H) films on molecular structure and resulting material properties with particular attention to elastic constant, cohesive fracture energy, and moisture-assisted cracking were investigated. Fourier transform infrared spectroscopy and x-ray photoelectron spectroscopy characterizations demonstrated that doped N primarily formed Si N and N H bonds, and doped O formed Si O suboxide bonds. The elastic constant of both N-doped a-SiC:H (a-SiCN:H) and O-doped a-SiC:H (a-SiCO:H) films increased with increasing N and O atomic concentrations (at.%). The cohesive fracture energy, G c , of the a-SiCN:H and a-SiCO:H films also increased with increasing N and O at.%. These increases in the mechanical properties of the films were attributed to film densification with increasing N and O at.%. The a-SiCN:H films exhibited a greater increase in G c than the a-SiCO:H films, which was due to the moisture-insensitivity of the a-SiCN:H films as opposed to the a-SiCO:H films. The a-SiCN:H films exhibited no moisture-assisted fracture behavior, which was attributed to moisture-insensitivity of Si N bonds due to their less polar nature.